src/ints/bios.cpp

/*
 *  Copyright (C) 2002-2020  The DOSBox Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <assert.h>
#include "dosbox.h"
#include "mem.h"
#include "cpu.h"
#include "bios.h"
#include "regs.h"
#include "cpu.h"
#include "callback.h"
#include "inout.h"
#include "pic.h"
#include "hardware.h"
#include "pci_bus.h"
#include "joystick.h"
#include "mouse.h"
#include "callback.h"
#include "setup.h"
#include "bios_disk.h"
#include "serialport.h"
#include "mapper.h"
#include "vga.h"
#include "shiftjis.h"
#include "pc98_gdc.h"
#include "pc98_gdc_const.h"
#include "regionalloctracking.h"
#include "build_timestamp.h"
extern bool PS1AudioCard;
#include "parport.h"
#include "dma.h"
#include <time.h>

#if defined(DB_HAVE_CLOCK_GETTIME) && ! defined(WIN32)
//time.h is already included
#else
#include <sys/timeb.h>
#endif

#if C_EMSCRIPTEN
# include <emscripten.h>
#endif

#if defined(_MSC_VER)
# pragma warning(disable:4244) /* const fmath::local::uint64_t to double possible loss of data */
# pragma warning(disable:4305) /* truncation from double to float */
#endif

#if defined(WIN32) && !defined(S_ISREG)
# define S_ISREG(x) ((x & S_IFREG) == S_IFREG)
#endif

/* NTS: The "Epson check" code in Windows 2.1 only compares up to the end of "NEC Corporation" */
const std::string pc98_copyright_str = "Copyright (C) 1983 by NEC Corporation / Microsoft Corp.\x0D\x0A";

/* more strange data involved in the "Epson check" */
const unsigned char pc98_epson_check_2[0x27] = {
    0x26,0x8A,0x05,0xA8,0x10,0x75,0x11,0xC6,0x06,0xD6,0x09,0x1B,0xC6,0x06,0xD7,0x09,
    0x4B,0xC6,0x06,0xD8,0x09,0x48,0xEB,0x0F,0xC6,0x06,0xD6,0x09,0x1A,0xC6,0x06,0xD7 ,
    0x09,0x70,0xC6,0x06,0xD8,0x09,0x71
};

bool enable_pc98_copyright_string = false;

/* mouse.cpp */
extern bool pc98_40col_text;
extern bool en_bios_ps2mouse;
extern bool rom_bios_8x8_cga_font;
extern bool pcibus_enable;

uint32_t Keyb_ig_status();
bool VM_Boot_DOSBox_Kernel();
Bit32u MEM_get_address_bits();
Bitu bios_post_parport_count();
Bitu bios_post_comport_count();
void pc98_update_cpu_page_ptr(void);
bool KEYBOARD_Report_BIOS_PS2Mouse();
bool gdc_5mhz_according_to_bios(void);
void pc98_update_display_page_ptr(void);
bool MEM_map_ROM_alias_physmem(Bitu start,Bitu end);
void pc98_update_palette(void);

bool bochs_port_e9 = false;
bool isa_memory_hole_512kb = false;
bool int15_wait_force_unmask_irq = false;

int unhandled_irq_method = UNHANDLED_IRQ_SIMPLE;

unsigned int reset_post_delay = 0;

Bitu call_irq_default = 0;
Bit16u biosConfigSeg=0;

Bitu BIOS_DEFAULT_IRQ0_LOCATION = ~0u;       // (RealMake(0xf000,0xfea5))
Bitu BIOS_DEFAULT_IRQ1_LOCATION = ~0u;       // (RealMake(0xf000,0xe987))
Bitu BIOS_DEFAULT_IRQ07_DEF_LOCATION = ~0u;  // (RealMake(0xf000,0xff55))
Bitu BIOS_DEFAULT_IRQ815_DEF_LOCATION = ~0u; // (RealMake(0xf000,0xe880))

Bitu BIOS_DEFAULT_HANDLER_LOCATION = ~0u;    // (RealMake(0xf000,0xff53))
Bitu BIOS_DEFAULT_INT5_LOCATION = ~0u;       // (RealMake(0xf000,0xff54))

Bitu BIOS_VIDEO_TABLE_LOCATION = ~0u;        // RealMake(0xf000,0xf0a4)
Bitu BIOS_VIDEO_TABLE_SIZE = 0u;

Bitu BIOS_DEFAULT_RESET_LOCATION = ~0u;      // RealMake(0xf000,0xe05b)

bool allow_more_than_640kb = false;

unsigned int APM_BIOS_connected_minor_version = 0;// what version the OS connected to us with. default to 1.0
unsigned int APM_BIOS_minor_version = 2;    // what version to emulate e.g to emulate 1.2 set this to 2

/* default bios type/version/date strings */
const char* const bios_type_string = "IBM COMPATIBLE 486 BIOS for DOSBox-X";
const char* const bios_version_string = "DOSBox-X BIOS v1.0";
const char* const bios_date_string = "01/01/92";

bool                        APM_inactivity_timer = true;

RegionAllocTracking             rombios_alloc;

Bitu                        rombios_minimum_location = 0xF0000; /* minimum segment allowed */
Bitu                        rombios_minimum_size = 0x10000;

bool MEM_map_ROM_physmem(Bitu start,Bitu end);
bool MEM_unmap_physmem(Bitu start,Bitu end);

static std::string bochs_port_e9_line;

static void bochs_port_e9_flush() {
    if (!bochs_port_e9_line.empty()) {
        LOG_MSG("Bochs port E9h: %s",bochs_port_e9_line.c_str());
        bochs_port_e9_line.clear();
    }
}

void bochs_port_e9_write(Bitu port,Bitu val,Bitu /*iolen*/) {
    (void)port;//UNUSED
    if (val == '\n' || val == '\r') {
        bochs_port_e9_flush();
    }
    else {
        bochs_port_e9_line += (char)val;
        if (bochs_port_e9_line.length() >= 256)
            bochs_port_e9_flush();
    }
}

void ROMBIOS_DumpMemory() {
    rombios_alloc.logDump();
}

void ROMBIOS_SanityCheck() {
    rombios_alloc.sanityCheck();
}

Bitu ROMBIOS_MinAllocatedLoc() {
    Bitu r = rombios_alloc.getMinAddress();

    if (r > (0x100000u - rombios_minimum_size))
        r = (0x100000u - rombios_minimum_size);

    return r & ~0xFFFu;
}

void ROMBIOS_FreeUnusedMinToLoc(Bitu phys) {
    Bitu new_phys;

    if (rombios_minimum_location & 0xFFF) E_Exit("ROMBIOS: FreeUnusedMinToLoc minimum location not page aligned");

    phys &= ~0xFFFUL;
    new_phys = rombios_alloc.freeUnusedMinToLoc(phys) & (~0xFFFUL);
    assert(new_phys >= phys);
    if (phys < new_phys) MEM_unmap_physmem(phys,new_phys-1);
    rombios_minimum_location = new_phys;
    ROMBIOS_SanityCheck();
    ROMBIOS_DumpMemory();
}

bool ROMBIOS_FreeMemory(Bitu phys) {
    return rombios_alloc.freeMemory(phys);
}

Bitu ROMBIOS_GetMemory(Bitu bytes,const char *who,Bitu alignment,Bitu must_be_at) {
    return rombios_alloc.getMemory(bytes,who,alignment,must_be_at);
}

void ROMBIOS_InitForCustomBIOS(void) {
    rombios_alloc.initSetRange(0xD8000,0xE0000);
}

static IO_Callout_t dosbox_int_iocallout = IO_Callout_t_none;

static unsigned char dosbox_int_register_shf = 0;
static uint32_t dosbox_int_register = 0;
static unsigned char dosbox_int_regsel_shf = 0;
static uint32_t dosbox_int_regsel = 0;
static bool dosbox_int_error = false;
static bool dosbox_int_busy = false;
static const char *dosbox_int_version = "DOSBox-X integration device v1.0";
static const char *dosbox_int_ver_read = NULL;

struct dosbox_int_saved_state {
    unsigned char   dosbox_int_register_shf;
    uint32_t        dosbox_int_register;
    unsigned char   dosbox_int_regsel_shf;
    uint32_t        dosbox_int_regsel;
    bool            dosbox_int_error;
    bool            dosbox_int_busy;
};

#define DOSBOX_INT_SAVED_STATE_MAX      4

struct dosbox_int_saved_state       dosbox_int_saved[DOSBOX_INT_SAVED_STATE_MAX];
int                                 dosbox_int_saved_sp = -1;

/* for use with interrupt handlers in DOS/Windows that need to save IG state
 * to ensure that IG state is restored on return in order to not interfere
 * with anything userspace is doing (as an alternative to wrapping all access
 * in CLI/STI or PUSHF/CLI/POPF) */
bool dosbox_int_push_save_state(void) {

    if (dosbox_int_saved_sp >= (DOSBOX_INT_SAVED_STATE_MAX-1))
        return false;

    struct dosbox_int_saved_state *ss = &dosbox_int_saved[++dosbox_int_saved_sp];

    ss->dosbox_int_register_shf =       dosbox_int_register_shf;
    ss->dosbox_int_register =           dosbox_int_register;
    ss->dosbox_int_regsel_shf =         dosbox_int_regsel_shf;
    ss->dosbox_int_regsel =             dosbox_int_regsel;
    ss->dosbox_int_error =              dosbox_int_error;
    ss->dosbox_int_busy =               dosbox_int_busy;
    return true;
}

bool dosbox_int_pop_save_state(void) {
    if (dosbox_int_saved_sp < 0)
        return false;

    struct dosbox_int_saved_state *ss = &dosbox_int_saved[dosbox_int_saved_sp--];

    dosbox_int_register_shf =           ss->dosbox_int_register_shf;
    dosbox_int_register =               ss->dosbox_int_register;
    dosbox_int_regsel_shf =             ss->dosbox_int_regsel_shf;
    dosbox_int_regsel =                 ss->dosbox_int_regsel;
    dosbox_int_error =                  ss->dosbox_int_error;
    dosbox_int_busy =                   ss->dosbox_int_busy;
    return true;
}

bool dosbox_int_discard_save_state(void) {
    if (dosbox_int_saved_sp < 0)
        return false;

    dosbox_int_saved_sp--;
    return true;
}

extern bool user_cursor_locked;
extern int user_cursor_x,user_cursor_y;
extern int user_cursor_sw,user_cursor_sh;
extern int master_cascade_irq;
extern bool enable_slave_pic;

static std::string dosbox_int_debug_out;

void VGA_SetCaptureStride(uint32_t v);
void VGA_SetCaptureAddress(uint32_t v);
void VGA_SetCaptureState(uint32_t v);
SDL_Rect &VGA_CaptureRectCurrent(void);
SDL_Rect &VGA_CaptureRectFromGuest(void);
uint32_t VGA_QueryCaptureAddress(void);
uint32_t VGA_QueryCaptureState(void);
uint32_t VGA_QuerySizeIG(void);

uint32_t Mixer_MIXQ(void);
uint32_t Mixer_MIXC(void);
void Mixer_MIXC_Write(uint32_t v);
PhysPt Mixer_MIXWritePos(void);
void Mixer_MIXWritePos_Write(PhysPt np);
void Mixer_MIXWriteBegin_Write(PhysPt np);
void Mixer_MIXWriteEnd_Write(PhysPt np);

/* read triggered, update the regsel */
void dosbox_integration_trigger_read() {
    dosbox_int_error = false;

    switch (dosbox_int_regsel) {
        case 0: /* Identification */
            dosbox_int_register = 0xD05B0740;
            break;
        case 1: /* test */
            break;
        case 2: /* version string */
            if (dosbox_int_ver_read == NULL)
                dosbox_int_ver_read = dosbox_int_version;

            dosbox_int_register = 0;
            for (Bitu i=0;i < 4;i++) {
                if (*dosbox_int_ver_read == 0) {
                    dosbox_int_ver_read = dosbox_int_version;
                    break;
                }

                dosbox_int_register += ((uint32_t)((unsigned char)(*dosbox_int_ver_read++))) << (uint32_t)(i * 8);
            }
            break;
        case 3: /* version number */
            dosbox_int_register = (0x01U/*major*/) + (0x00U/*minor*/ << 8U) + (0x00U/*subver*/ << 16U) + (0x01U/*bump*/ << 24U);
            break;
        case 4: /* current emulator time as 16.16 fixed point */
            dosbox_int_register = (uint32_t)(PIC_FullIndex() * 0x10000);
            break;

        case 0x5158494D: /* query mixer output 'MIXQ' */
            /* bits [19:0] = sample rate in Hz or 0 if mixer is not mixing AT ALL
             * bits [23:20] = number of channels (at this time, always 2 aka stereo)
             * bits [29:29] = 1=swap stereo  0=normal
             * bits [30:30] = 1=muted  0=not muted
             * bits [31:31] = 1=sound  0=nosound */
            dosbox_int_register = Mixer_MIXQ();
            break;

        case 0x4358494D: /* query mixer output 'MIXC' */
            dosbox_int_register = Mixer_MIXC();
            break;

        case 0x5058494D: /* query mixer output 'MIXP' */
            dosbox_int_register = Mixer_MIXWritePos();
            break;

        case 0x4258494D: /* query mixer output 'MIXB' */
            break;

        case 0x4558494D: /* query mixer output 'MIXE' */
            break;

        case 0x6845C0: /* query VGA display size */
            dosbox_int_register = VGA_QuerySizeIG();
            break;

        case 0x6845C1: /* query VGA capture state */
            dosbox_int_register = VGA_QueryCaptureState();
            break;

        case 0x6845C2: /* query VGA capture address (what is being captured to NOW) */
            dosbox_int_register = VGA_QueryCaptureAddress();
            break;

        case 0x6845C3: /* query VGA capture current crop rectangle (position) will not reflect new rectangle until VGA capture finishes capture. */
            {
                const SDL_Rect &r = VGA_CaptureRectCurrent();
                dosbox_int_register = ((uint32_t)r.y << (uint32_t)16ul) + (uint32_t)r.x;
            }
            break;

        case 0x6845C4: /* query VGA capture current crop rectangle (size). will not reflect new rectangle until VGA capture finishes capture. */
            {
                const SDL_Rect &r = VGA_CaptureRectCurrent();
                dosbox_int_register = ((uint32_t)r.h << (uint32_t)16ul) + (uint32_t)r.w;
            }
            break;

        case 0x825901: /* PIC configuration */
            /* bits [7:0] = cascade interrupt or 0xFF if none
             * bit  [8:8] = primary PIC present
             * bit  [9:9] = secondary PIC present */
            if (master_cascade_irq >= 0)
                dosbox_int_register = ((unsigned int)master_cascade_irq & 0xFFu);
            else
                dosbox_int_register = 0xFFu;

            dosbox_int_register |= 0x100; // primary always present
            if (enable_slave_pic) dosbox_int_register |= 0x200;
            break;

        case 0x823780: /* ISA DMA injection, single byte/word (read from memory) */
            break;

//      case 0x804200: /* keyboard input injection -- not supposed to read */
//          break;

        case 0x804201: /* keyboard status */
            dosbox_int_register = Keyb_ig_status();
            break;

        case 0x434D54: /* read user mouse status */
            dosbox_int_register =
                (user_cursor_locked ? (1UL << 0UL) : 0UL);      /* bit 0 = mouse capture lock */
            break;

        case 0x434D55: /* read user mouse cursor position */
            dosbox_int_register = (Bit32u((Bit16u)user_cursor_y & 0xFFFFUL) << 16UL) | Bit32u((Bit16u)user_cursor_x & 0xFFFFUL);
            break;

        case 0x434D56: { /* read user mouse cursor position (normalized for Windows 3.x) */
            signed long long x = ((signed long long)user_cursor_x << 16LL) / (signed long long)(user_cursor_sw-1);
            signed long long y = ((signed long long)user_cursor_y << 16LL) / (signed long long)(user_cursor_sh-1);
            if (x < 0x0000LL) x = 0x0000LL;
            if (x > 0xFFFFLL) x = 0xFFFFLL;
            if (y < 0x0000LL) y = 0x0000LL;
            if (y > 0xFFFFLL) y = 0xFFFFLL;
            dosbox_int_register = ((unsigned int)y << 16UL) | (unsigned int)x;
            } break;

        case 0xC54010: /* Screenshot/capture trigger */
            /* TODO: This should also be hidden behind an enable switch, so that rogue DOS development
             *       can't retaliate if the user wants to capture video or screenshots. */
#if (C_SSHOT)
            dosbox_int_register = 0x00000000; // available
            if (CaptureState & CAPTURE_IMAGE)
                dosbox_int_register |= 1 << 0; // Image capture is in progress
            if (CaptureState & CAPTURE_VIDEO)
                dosbox_int_register |= 1 << 1; // Video capture is in progress
            if (CaptureState & CAPTURE_WAVE)
                dosbox_int_register |= 1 << 2; // WAVE capture is in progress
#else
            dosbox_int_register = 0xC0000000; // not available (bit 31 set), not enabled (bit 30 set)
#endif
            break;

        case 0xAA55BB66UL: /* interface reset result */
            break;

        default:
            dosbox_int_register = 0xAA55AA55;
            dosbox_int_error = true;
            break;
    }

    LOG(LOG_MISC,LOG_DEBUG)("DOSBox integration read 0x%08lx got 0x%08lx (err=%u)\n",
        (unsigned long)dosbox_int_regsel,
        (unsigned long)dosbox_int_register,
        dosbox_int_error?1:0);
}

bool watchdog_set = false;

void Watchdog_Timeout_Event(Bitu /*val*/) {
    LOG_MSG("Watchdog timeout occurred");
    CPU_Raise_NMI();
}

void Watchdog_Timer_Clear(void) {
    if (watchdog_set) {
        PIC_RemoveEvents(Watchdog_Timeout_Event);
        watchdog_set = false;
    }
}

void Watchdog_Timer_Set(uint32_t timeout_ms) {
    Watchdog_Timer_Clear();

    if (timeout_ms != 0) {
        watchdog_set = true;
        PIC_AddEvent(Watchdog_Timeout_Event,(double)timeout_ms);
    }
}

unsigned int mouse_notify_mode = 0;
// 0 = off
// 1 = trigger as PS/2 mouse interrupt

/* write triggered */
void dosbox_integration_trigger_write() {
    dosbox_int_error = false;

    LOG(LOG_MISC,LOG_DEBUG)("DOSBox integration write 0x%08lx val 0x%08lx\n",
        (unsigned long)dosbox_int_regsel,
        (unsigned long)dosbox_int_register);

    switch (dosbox_int_regsel) {
        case 1: /* test */
            break;

        case 2: /* version string */
            dosbox_int_ver_read = NULL;
            break;

        case 0xDEB0: /* debug output (to log) */
            for (unsigned int b=0;b < 4;b++) {
                unsigned char c = (unsigned char)(dosbox_int_register >> (b * 8U));
                if (c == '\n' || dosbox_int_debug_out.length() >= 200) {
                    LOG_MSG("Client debug message: %s\n",dosbox_int_debug_out.c_str());
                    dosbox_int_debug_out.clear();
                }
                else if (c != 0) {
                    dosbox_int_debug_out += ((char)c);
                }
                else {
                    break;
                }
            }
            dosbox_int_register = 0;
            break;

        case 0xDEB1: /* debug output clear */
            dosbox_int_debug_out.clear();
            break;

        case 0x6845C1: /* query VGA capture state */
            VGA_SetCaptureState(dosbox_int_register);
            break;

        case 0x6845C2: /* set VGA capture address, will be applied to next capture */
            VGA_SetCaptureAddress(dosbox_int_register);
            break;

        case 0x6845C3: /* set VGA capture crop rectangle (position), will be applied to next capture */
            {
                SDL_Rect &r = VGA_CaptureRectFromGuest();
                r.x = (int)(dosbox_int_register & 0xFFFF);
                r.y = (int)(dosbox_int_register >> 16ul);
            }
            break;

        case 0x6845C4: /* set VGA capture crop rectangle (size), will be applied to next capture */
            {
                SDL_Rect &r = VGA_CaptureRectFromGuest();
                r.w = (int)(dosbox_int_register & 0xFFFF);
                r.h = (int)(dosbox_int_register >> 16ul);
            }
            break;

        case 0x6845C5: /* set VGA capture stride (bytes per scan line) */
            VGA_SetCaptureStride(dosbox_int_register);
            break;

        case 0x52434D: /* release mouse capture 'MCR' */
            void GFX_ReleaseMouse(void);
            GFX_ReleaseMouse();
            break;

        case 0x5158494D: /* query mixer output 'MIXQ' */
            break;

        case 0x4358494D: /* query mixer output 'MIXC' */
            Mixer_MIXC_Write(dosbox_int_register);
            break;

        case 0x5058494D: /* query mixer output 'MIXP' */
            Mixer_MIXWritePos_Write(dosbox_int_register);
            break;

        case 0x4258494D: /* query mixer output 'MIXB' */
            Mixer_MIXWriteBegin_Write(dosbox_int_register);
            break;

        case 0x4558494D: /* query mixer output 'MIXE' */
            Mixer_MIXWriteEnd_Write(dosbox_int_register);
            break;

        case 0x57415444: /* Set/clear watchdog timer 'WATD' */
            Watchdog_Timer_Set(dosbox_int_register);
            break;

        case 0x808602: /* NMI (INT 02h) interrupt injection */
            {
                dosbox_int_register_shf = 0;
                dosbox_int_regsel_shf = 0;
                CPU_Raise_NMI();
            }
            break;

        case 0x825900: /* PIC interrupt injection */
            {
                dosbox_int_register_shf = 0;
                dosbox_int_regsel_shf = 0;
                /* bits  [7:0]  = IRQ to signal (must be 0-15)
                 * bit   [8:8]  = 1=raise 0=lower IRQ */
                uint8_t IRQ = dosbox_int_register&0xFFu;
                bool raise = (dosbox_int_register>>8u)&1u;

                if (IRQ < 16) {
                    if (raise)
                        PIC_ActivateIRQ(IRQ);
                    else
                        PIC_DeActivateIRQ(IRQ);
                }
            }
            break;

        case 0x823700: /* ISA DMA injection, single byte/word (write to memory) */
            {
                dosbox_int_register_shf = 0;
                dosbox_int_regsel_shf = 0;
                /* bits  [7:0]  = data byte if 8-bit DNA
                 * bits [15:0]  = data word if 16-bit DMA
                 * bits [18:16] = DMA channel to send to */
                DmaChannel *ch = GetDMAChannel(((unsigned int)dosbox_int_register>>16u)&7u);
                if (ch != NULL) {
                    unsigned char tmp[2];

                    tmp[0] = (unsigned char)( dosbox_int_register         & 0xFFu);
                    tmp[1] = (unsigned char)((dosbox_int_register >>  8u) & 0xFFu);

                    /* NTS: DMA channel write will write tmp[0] if 8-bit, tmp[0]/tmp[1] if 16-bit */
                    if (ch->Write(1/*one unit of transfer*/,tmp) == 1) {
                        dosbox_int_register = 0;
                        dosbox_int_error = false;
                    }
                    else {
                        dosbox_int_register = 0x823700;
                        dosbox_int_error = true;
                    }
                }
                else {
                    dosbox_int_register = 0x8237FF;
                    dosbox_int_error = true;
                }
            }
            break;

        case 0x823780: /* ISA DMA injection, single byte/word (read from memory) */
            {
                dosbox_int_register_shf = 0;
                dosbox_int_regsel_shf = 0;
                /* bits [18:16] = DMA channel to send to */
                DmaChannel *ch = GetDMAChannel(((unsigned int)dosbox_int_register>>16u)&7u);
                if (ch != NULL) {
                    unsigned char tmp[2];

                    /* NTS: DMA channel write will write tmp[0] if 8-bit, tmp[0]/tmp[1] if 16-bit */
                    tmp[0] = tmp[1] = 0;
                    if (ch->Read(1/*one unit of transfer*/,tmp) == 1) {
                        dosbox_int_register = ((unsigned int)tmp[1] << 8u) + (unsigned int)tmp[0];
                        dosbox_int_error = false;
                    }
                    else {
                        dosbox_int_register = 0x823700;
                        dosbox_int_error = true;
                    }
                }
                else {
                    dosbox_int_register = 0x8237FF;
                    dosbox_int_error = true;
                }
            }
            break;

        case 0x804200: /* keyboard input injection */
            void Mouse_ButtonPressed(Bit8u button);
            void Mouse_ButtonReleased(Bit8u button);
            void pc98_keyboard_send(const unsigned char b);
            void Mouse_CursorMoved(float xrel,float yrel,float x,float y,bool emulate);
            void KEYBOARD_AUX_Event(float x,float y,Bitu buttons,int scrollwheel);
            void KEYBOARD_AddBuffer(Bit16u data);

            switch ((dosbox_int_register>>8)&0xFF) {
                case 0x00: // keyboard
                    if (IS_PC98_ARCH)
                        pc98_keyboard_send(dosbox_int_register&0xFF);
                    else
                        KEYBOARD_AddBuffer(dosbox_int_register&0xFF);
                    break;
                case 0x01: // AUX
                    if (!IS_PC98_ARCH)
                        KEYBOARD_AddBuffer((dosbox_int_register&0xFF)|0x100/*AUX*/);
                    else   // no such interface in PC-98 mode
                        dosbox_int_error = true;
                    break;
                case 0x08: // mouse button injection
                    if (dosbox_int_register&0x80) Mouse_ButtonPressed(dosbox_int_register&0x7F);
                    else Mouse_ButtonReleased(dosbox_int_register&0x7F);
                    break;
                case 0x09: // mouse movement injection (X)
                    Mouse_CursorMoved(((dosbox_int_register>>16UL) / 256.0f) - 1.0f,0,0,0,true);
                    break;
                case 0x0A: // mouse movement injection (Y)
                    Mouse_CursorMoved(0,((dosbox_int_register>>16UL) / 256.0f) - 1.0f,0,0,true);
                    break;
                case 0x0B: // mouse scrollwheel injection
                    // TODO
                    break;
                default:
                    dosbox_int_error = true;
                    break;
            }
            break;

//      case 0x804201: /* keyboard status do not write */
//          break;

        /* this command is used to enable notification of mouse movement over the windows even if the mouse isn't captured */
        case 0x434D55: /* read user mouse cursor position */
        case 0x434D56: /* read user mouse cursor position (normalized for Windows 3.x) */
            mouse_notify_mode = dosbox_int_register & 0xFF;
            LOG(LOG_MISC,LOG_DEBUG)("Mouse notify mode=%u",mouse_notify_mode);
            break;
 
        case 0xC54010: /* Screenshot/capture trigger */
#if (C_SSHOT)
            void CAPTURE_ScreenShotEvent(bool pressed);
            void CAPTURE_VideoEvent(bool pressed);
#endif
            void CAPTURE_WaveEvent(bool pressed);

            /* TODO: It would be wise to grant/deny access to this register through another dosbox.conf option
             *       so that rogue DOS development cannot shit-spam the capture folder */
#if (C_SSHOT)
            if (dosbox_int_register & 1)
                CAPTURE_ScreenShotEvent(true);
            if (dosbox_int_register & 2)
                CAPTURE_VideoEvent(true);
#endif
            if (dosbox_int_register & 4)
                CAPTURE_WaveEvent(true);
            break;

        default:
            dosbox_int_register = 0x55AA55AA;
            dosbox_int_error = true;
            break;
    }
}

/* PORT 0x28: Index
 *      0x29: Data
 *      0x2A: Status(R) or Command(W)
 *      0x2B: Not yet assigned
 *
 *      Registers are 32-bit wide. I/O to index and data rotate through the
 *      bytes of the register depending on I/O length, meaning that one 32-bit
 *      I/O read will read the entire register, while four 8-bit reads will
 *      read one byte out of 4. */

static Bitu dosbox_integration_port00_index_r(Bitu port,Bitu iolen) {
    (void)port;//UNUSED
    Bitu retb = 0;
    Bitu ret = 0;

    while (iolen > 0) {
        ret += ((dosbox_int_regsel >> (dosbox_int_regsel_shf * 8)) & 0xFFU) << (retb * 8);
        if ((++dosbox_int_regsel_shf) >= 4) dosbox_int_regsel_shf = 0;
        iolen--;
        retb++;
    }

    return ret;
}

static void dosbox_integration_port00_index_w(Bitu port,Bitu val,Bitu iolen) {
    (void)port;//UNUSED

    while (iolen > 0) {
        uint32_t msk = 0xFFU << (dosbox_int_regsel_shf * 8);
        dosbox_int_regsel = (dosbox_int_regsel & ~msk) + ((val & 0xFF) << (dosbox_int_regsel_shf * 8));
        if ((++dosbox_int_regsel_shf) >= 4) dosbox_int_regsel_shf = 0;
        val >>= 8U;
        iolen--;
    }
}

static Bitu dosbox_integration_port01_data_r(Bitu port,Bitu iolen) {
    (void)port;//UNUSED
    Bitu retb = 0;
    Bitu ret = 0;

    while (iolen > 0) {
        if (dosbox_int_register_shf == 0) dosbox_integration_trigger_read();
        ret += ((dosbox_int_register >> (dosbox_int_register_shf * 8)) & 0xFFU) << (retb * 8);
        if ((++dosbox_int_register_shf) >= 4) dosbox_int_register_shf = 0;
        iolen--;
        retb++;
    }

    return ret;
}

static void dosbox_integration_port01_data_w(Bitu port,Bitu val,Bitu iolen) {
    (void)port;//UNUSED

    while (iolen > 0) {
        uint32_t msk = 0xFFU << (dosbox_int_register_shf * 8);
        dosbox_int_register = (dosbox_int_register & ~msk) + ((val & 0xFF) << (dosbox_int_register_shf * 8));
        if ((++dosbox_int_register_shf) >= 4) dosbox_int_register_shf = 0;
        if (dosbox_int_register_shf == 0) dosbox_integration_trigger_write();
        val >>= 8U;
        iolen--;
    }
}

static Bitu dosbox_integration_port02_status_r(Bitu port,Bitu iolen) {
    (void)iolen;//UNUSED
    (void)port;//UNUSED
    /* status */
    /* 7:6 = regsel byte index
     * 5:4 = register byte index
     * 3:2 = reserved
     *   1 = error
     *   0 = busy */
    return
        ((unsigned int)dosbox_int_regsel_shf << 6u) + ((unsigned int)dosbox_int_register_shf << 4u) +
        (dosbox_int_error ? 2u : 0u) + (dosbox_int_busy ? 1u : 0u);
}

static void dosbox_integration_port02_command_w(Bitu port,Bitu val,Bitu iolen) {
    (void)port;
    (void)iolen;
    switch (val) {
        case 0x00: /* reset latch */
            dosbox_int_register_shf = 0;
            dosbox_int_regsel_shf = 0;
            break;
        case 0x01: /* flush write */
            if (dosbox_int_register_shf != 0) {
                dosbox_integration_trigger_write();
                dosbox_int_register_shf = 0;
            }
            break;
        case 0x20: /* push state */
            if (dosbox_int_push_save_state()) {
                dosbox_int_register_shf = 0;
                dosbox_int_regsel_shf = 0;
                dosbox_int_error = false;
                dosbox_int_busy = false;
                dosbox_int_regsel = 0xAA55BB66;
                dosbox_int_register = 0xD05B0C5;
                LOG(LOG_MISC,LOG_DEBUG)("DOSBOX IG state saved");
            }
            else {
                LOG(LOG_MISC,LOG_DEBUG)("DOSBOX IG unable to push state, stack overflow");
                dosbox_int_error = true;
            }
            break;
        case 0x21: /* pop state */
            if (dosbox_int_pop_save_state()) {
                LOG(LOG_MISC,LOG_DEBUG)("DOSBOX IG state restored");
            }
            else {
                LOG(LOG_MISC,LOG_DEBUG)("DOSBOX IG unable to pop state, stack underflow");
                dosbox_int_error = true;
            }
            break;
        case 0x22: /* discard state */
            if (dosbox_int_discard_save_state()) {
                LOG(LOG_MISC,LOG_DEBUG)("DOSBOX IG state discarded");
            }
            else {
                LOG(LOG_MISC,LOG_DEBUG)("DOSBOX IG unable to discard state, stack underflow");
                dosbox_int_error = true;
            }
            break;
        case 0x23: /* discard all state */
            while (dosbox_int_discard_save_state());
            break;
        case 0xFE: /* clear error */
            dosbox_int_error = false;
            break;
        case 0xFF: /* reset interface */
            dosbox_int_busy = false;
            dosbox_int_error = false;
            dosbox_int_regsel = 0xAA55BB66;
            dosbox_int_register = 0xD05B0C5;
            break;
        default:
            dosbox_int_error = true;
            break;
    }
}

static IO_ReadHandler* const dosbox_integration_cb_ports_r[4] = {
    dosbox_integration_port00_index_r,
    dosbox_integration_port01_data_r,
    dosbox_integration_port02_status_r,
    NULL
};

static IO_ReadHandler* dosbox_integration_cb_port_r(IO_CalloutObject &co,Bitu port,Bitu iolen) {
    (void)co;
    (void)iolen;
    return dosbox_integration_cb_ports_r[port&3];
}

static IO_WriteHandler* const dosbox_integration_cb_ports_w[4] = {
    dosbox_integration_port00_index_w,
    dosbox_integration_port01_data_w,
    dosbox_integration_port02_command_w,
    NULL
};

static IO_WriteHandler* dosbox_integration_cb_port_w(IO_CalloutObject &co,Bitu port,Bitu iolen) {
    (void)co;
    (void)iolen;
    return dosbox_integration_cb_ports_w[port&3];
}

/* if mem_systems 0 then size_extended is reported as the real size else 
 * zero is reported. ems and xms can increase or decrease the other_memsystems
 * counter using the BIOS_ZeroExtendedSize call */
static Bit16u size_extended;
static unsigned int ISA_PNP_WPORT = 0x20B;
static unsigned int ISA_PNP_WPORT_BIOS = 0;
static IO_ReadHandleObject *ISAPNP_PNP_READ_PORT = NULL;        /* 0x200-0x3FF range */
static IO_WriteHandleObject *ISAPNP_PNP_ADDRESS_PORT = NULL;        /* 0x279 */
static IO_WriteHandleObject *ISAPNP_PNP_DATA_PORT = NULL;       /* 0xA79 */
static IO_WriteHandleObject *BOCHS_PORT_E9 = NULL;
//static unsigned char ISA_PNP_CUR_CSN = 0;
static unsigned char ISA_PNP_CUR_ADDR = 0;
static unsigned char ISA_PNP_CUR_STATE = 0;
enum {
    ISA_PNP_WAIT_FOR_KEY=0,
    ISA_PNP_SLEEP,
    ISA_PNP_ISOLATE,
    ISA_PNP_CONFIG
};

const unsigned char isa_pnp_init_keystring[32] = {
    0x6A,0xB5,0xDA,0xED,0xF6,0xFB,0x7D,0xBE,
    0xDF,0x6F,0x37,0x1B,0x0D,0x86,0xC3,0x61,
    0xB0,0x58,0x2C,0x16,0x8B,0x45,0xA2,0xD1,
    0xE8,0x74,0x3A,0x9D,0xCE,0xE7,0x73,0x39
};

static RealPt INT15_apm_pmentry=0;
static unsigned char ISA_PNP_KEYMATCH=0;
static Bits other_memsystems=0;
static bool apm_realmode_connected = false;
void CMOS_SetRegister(Bitu regNr, Bit8u val); //For setting equipment word
bool enable_integration_device_pnp=false;
bool enable_integration_device=false;
bool ISAPNPBIOS=false;
bool APMBIOS=false;
bool APMBIOS_pnp=false;
bool APMBIOS_allow_realmode=false;
bool APMBIOS_allow_prot16=false;
bool APMBIOS_allow_prot32=false;
int APMBIOS_connect_mode=0;

enum {
    APMBIOS_CONNECT_REAL=0,
    APMBIOS_CONNECT_PROT16,
    APMBIOS_CONNECT_PROT32
};

unsigned int APMBIOS_connected_already_err() {
    switch (APMBIOS_connect_mode) {
        case APMBIOS_CONNECT_REAL:  return 0x02;
        case APMBIOS_CONNECT_PROT16:    return 0x05;
        case APMBIOS_CONNECT_PROT32:    return 0x07;
    }

    return 0x00;
}

ISAPnPDevice::ISAPnPDevice() {
    memset(ident,0,sizeof(ident));
}

bool ISAPnPDevice::alloc(size_t sz) {
    if (sz == alloc_sz)
        return true;

    if (alloc_res == resource_data) {
        resource_data_len = 0;
        resource_data_pos = 0;
        resource_data = NULL;
    }
    if (alloc_res != NULL)
        delete[] alloc_res;

    alloc_res = NULL;
    alloc_write = 0;
    alloc_sz = 0;

    if (sz == 0)
        return true;
    if (sz > 65536)
        return false;

    alloc_res = new unsigned char[sz];
    if (alloc_res == NULL) return false;
    memset(alloc_res,0xFF,sz);
    alloc_sz = sz;
    return true;
}

ISAPnPDevice::~ISAPnPDevice() {
    ISAPnPDevice::alloc(0);
}

void ISAPnPDevice::begin_write_res() {
    if (alloc_res == NULL) return;

    resource_data_pos = 0;
    resource_data_len = 0;
    resource_data = NULL;
    alloc_write = 0;
}

void ISAPnPDevice::write_byte(const unsigned char c) {
    if (alloc_res == NULL || alloc_write >= alloc_sz) return;
    alloc_res[alloc_write++] = c;
}

void ISAPnPDevice::write_begin_SMALLTAG(const ISAPnPDevice::SmallTags stag,unsigned char len) {
    if (len >= 8 || (unsigned int)stag >= 0x10) return;
    write_byte(((unsigned char)stag << 3) + len);
}

void ISAPnPDevice::write_begin_LARGETAG(const ISAPnPDevice::LargeTags stag,unsigned int len) {
    if (len >= 4096) return;
    write_byte(0x80 + ((unsigned char)stag));
    write_byte(len & 0xFF);
    write_byte(len >> 8);
}

void ISAPnPDevice::write_Device_ID(const char c1,const char c2,const char c3,const char c4,const char c5,const char c6,const char c7) {
    write_byte((((unsigned char)c1 & 0x1FU) << 2) + (((unsigned char)c2 & 0x18U) >> 3));
    write_byte((((unsigned char)c2 & 0x07U) << 5) + ((unsigned char)c3 & 0x1FU));
    write_byte((((unsigned char)c4 & 0x0FU) << 4) + ((unsigned char)c5 & 0x0FU));
    write_byte((((unsigned char)c6 & 0x0FU) << 4) + ((unsigned char)c7 & 0x0FU));
}

void ISAPnPDevice::write_Logical_Device_ID(const char c1,const char c2,const char c3,const char c4,const char c5,const char c6,const char c7) {
    write_begin_SMALLTAG(SmallTags::LogicalDeviceID,5);
    write_Device_ID(c1,c2,c3,c4,c5,c6,c7);
    write_byte(0x00);
}

void ISAPnPDevice::write_Compatible_Device_ID(const char c1,const char c2,const char c3,const char c4,const char c5,const char c6,const char c7) {
    write_begin_SMALLTAG(SmallTags::CompatibleDeviceID,4);
    write_Device_ID(c1,c2,c3,c4,c5,c6,c7);
}

void ISAPnPDevice::write_IRQ_Format(const uint16_t IRQ_mask,const unsigned char IRQ_signal_type) {
    bool write_irq_info = (IRQ_signal_type != 0);

    write_begin_SMALLTAG(SmallTags::IRQFormat,write_irq_info?3:2);
    write_byte(IRQ_mask & 0xFF);
    write_byte(IRQ_mask >> 8);
    if (write_irq_info) write_byte(((unsigned char)IRQ_signal_type & 0x0F));
}

void ISAPnPDevice::write_DMA_Format(const uint8_t DMA_mask,const unsigned char transfer_type_preference,const bool is_bus_master,const bool byte_mode,const bool word_mode,const unsigned char speed_supported) {
    write_begin_SMALLTAG(SmallTags::DMAFormat,2);
    write_byte(DMA_mask);
    write_byte(
        (transfer_type_preference & 0x03) |
        (is_bus_master ? 0x04 : 0x00) |
        (byte_mode ? 0x08 : 0x00) |
        (word_mode ? 0x10 : 0x00) |
        ((speed_supported & 3) << 5));
}

void ISAPnPDevice::write_IO_Port(const uint16_t min_port,const uint16_t max_port,const uint8_t count,const uint8_t alignment,const bool full16bitdecode) {
    write_begin_SMALLTAG(SmallTags::IOPortDescriptor,7);
    write_byte((full16bitdecode ? 0x01 : 0x00));
    write_byte(min_port & 0xFF);
    write_byte(min_port >> 8);
    write_byte(max_port & 0xFF);
    write_byte(max_port >> 8);
    write_byte(alignment);
    write_byte(count);
}

void ISAPnPDevice::write_Dependent_Function_Start(const ISAPnPDevice::DependentFunctionConfig cfg,const bool force) {
    bool write_cfg_byte = force || (cfg != ISAPnPDevice::DependentFunctionConfig::AcceptableDependentConfiguration);

    write_begin_SMALLTAG(SmallTags::StartDependentFunctions,write_cfg_byte ? 1 : 0);
    if (write_cfg_byte) write_byte((unsigned char)cfg);
}

void ISAPnPDevice::write_End_Dependent_Functions() {
    write_begin_SMALLTAG(SmallTags::EndDependentFunctions,0);
}

void ISAPnPDevice::write_nstring(const char *str,const size_t l) {
    (void)l;

    if (alloc_res == NULL || alloc_write >= alloc_sz) return;

    while (*str != 0 && alloc_write < alloc_sz)
        alloc_res[alloc_write++] = (unsigned char)(*str++);
}

void ISAPnPDevice::write_Identifier_String(const char *str) {
    const size_t l = strlen(str);
    if (l > 4096) return;

    write_begin_LARGETAG(LargeTags::IdentifierStringANSI,(unsigned int)l);
    if (l != 0) write_nstring(str,l);
}

void ISAPnPDevice::write_ISAPnP_version(unsigned char major,unsigned char minor,unsigned char vendor) {
    write_begin_SMALLTAG(SmallTags::PlugAndPlayVersionNumber,2);
    write_byte((major << 4) + minor);
    write_byte(vendor);
}

void ISAPnPDevice::write_END() {
    unsigned char sum = 0;
    size_t i;

    write_begin_SMALLTAG(SmallTags::EndTag,/*length*/1);

    for (i=0;i < alloc_write;i++) sum += alloc_res[i];
    write_byte((0x100 - sum) & 0xFF);
}

void ISAPnPDevice::end_write_res() {
    if (alloc_res == NULL) return;

    write_END();

    if (alloc_write >= alloc_sz) LOG(LOG_MISC,LOG_WARN)("ISA PNP generation overflow");

    resource_data_pos = 0;
    resource_data_len = alloc_sz; // the device usually has a reason for allocating the fixed size it does
    resource_data = alloc_res;
    alloc_write = 0;
}

void ISAPnPDevice::config(Bitu val) {
    (void)val;
}

void ISAPnPDevice::wakecsn(Bitu val) {
    (void)val;
    ident_bp = 0;
    ident_2nd = 0;
    resource_data_pos = 0;
    resource_ident = 0;
}

void ISAPnPDevice::select_logical_device(Bitu val) {
    (void)val;
}
    
void ISAPnPDevice::checksum_ident() {
    unsigned char checksum = 0x6a,bit;
    int i,j;

    for (i=0;i < 8;i++) {
        for (j=0;j < 8;j++) {
            bit = (ident[i] >> j) & 1;
            checksum = ((((checksum ^ (checksum >> 1)) & 1) ^ bit) << 7) | (checksum >> 1);
        }
    }

    ident[8] = checksum;
}

void ISAPnPDevice::on_pnp_key() {
    resource_ident = 0;
}

uint8_t ISAPnPDevice::read(Bitu addr) {
    (void)addr;
    return 0x00;
}

void ISAPnPDevice::write(Bitu addr,Bitu val) {
    (void)addr;
    (void)val;
}

#define MAX_ISA_PNP_DEVICES     64
#define MAX_ISA_PNP_SYSDEVNODES     256

static ISAPnPDevice *ISA_PNP_selected = NULL;
static ISAPnPDevice *ISA_PNP_devs[MAX_ISA_PNP_DEVICES] = {NULL}; /* FIXME: free objects on shutdown */
static Bitu ISA_PNP_devnext = 0;

static const unsigned char ISAPnPIntegrationDevice_sysdev[] = {
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x28,0x28,              /* min-max range I/O port */
            0x04,0x04),             /* align=4 length=4 */
    ISAPNP_END
};

class ISAPnPIntegrationDevice : public ISAPnPDevice {
    public:
        ISAPnPIntegrationDevice() : ISAPnPDevice() {
            resource_ident = 0;
            resource_data = (unsigned char*)ISAPnPIntegrationDevice_sysdev;
            resource_data_len = sizeof(ISAPnPIntegrationDevice_sysdev);
            host_writed(ident+0,ISAPNP_ID('D','O','S',0x1,0x2,0x3,0x4)); /* DOS1234 test device */
            host_writed(ident+4,0xFFFFFFFFUL);
            checksum_ident();
        }
};

ISAPnPIntegrationDevice *isapnpigdevice = NULL;

class ISAPNP_SysDevNode {
public:
    ISAPNP_SysDevNode(const unsigned char *ir,size_t len,bool already_alloc=false) {
        if (already_alloc) {
            raw = (unsigned char*)ir;
            raw_len = len;
            own = false;
        }
        else {
            if (len > 65535) E_Exit("ISAPNP_SysDevNode data too long");
            raw = new unsigned char[(size_t)len+1u];
            if (ir == NULL)
                E_Exit("ISAPNP_SysDevNode cannot allocate buffer");
            else
                memcpy(raw, ir, (size_t)len);
            raw_len = len;
            raw[len] = 0;
            own = true;
        }
    }
    virtual ~ISAPNP_SysDevNode() {
        if (own) delete[] raw;
    }

    unsigned char*      raw;
    size_t              raw_len;
    bool                own;
};

static ISAPNP_SysDevNode*   ISAPNP_SysDevNodes[MAX_ISA_PNP_SYSDEVNODES] = {NULL};
static Bitu         ISAPNP_SysDevNodeLargest=0;
static Bitu         ISAPNP_SysDevNodeCount=0;

void ISA_PNP_FreeAllSysNodeDevs() {
    Bitu i;

    for (i=0;i < MAX_ISA_PNP_SYSDEVNODES;i++) {
        if (ISAPNP_SysDevNodes[i] != NULL) delete ISAPNP_SysDevNodes[i];
        ISAPNP_SysDevNodes[i] = NULL;
    }

    ISAPNP_SysDevNodeLargest=0;
    ISAPNP_SysDevNodeCount=0;
}

void ISA_PNP_FreeAllDevs() {
    Bitu i;

    for (i=0;i < MAX_ISA_PNP_DEVICES;i++) {
        if (ISA_PNP_devs[i] != NULL) {
            delete ISA_PNP_devs[i];
            ISA_PNP_devs[i] = NULL;
        }
    }
    for (i=0;i < MAX_ISA_PNP_SYSDEVNODES;i++) {
        if (ISAPNP_SysDevNodes[i] != NULL) delete ISAPNP_SysDevNodes[i];
        ISAPNP_SysDevNodes[i] = NULL;
    }

    ISAPNP_SysDevNodeLargest=0;
    ISAPNP_SysDevNodeCount=0;
}

void ISA_PNP_devreg(ISAPnPDevice *x) {
    if (ISA_PNP_devnext < MAX_ISA_PNP_DEVICES) {
        if (ISA_PNP_WPORT_BIOS == 0) ISA_PNP_WPORT_BIOS = ISA_PNP_WPORT;
        ISA_PNP_devs[ISA_PNP_devnext++] = x;
        x->CSN = ISA_PNP_devnext;
    }
}

static Bitu isapnp_read_port(Bitu port,Bitu /*iolen*/) {
    (void)port;//UNUSED
    Bitu ret=0xff;

    switch (ISA_PNP_CUR_ADDR) {
        case 0x01:  /* serial isolation */
               if (ISA_PNP_selected && ISA_PNP_selected->CSN == 0) {
                   if (ISA_PNP_selected->ident_bp < 72) {
                       if (ISA_PNP_selected->ident[ISA_PNP_selected->ident_bp>>3] & (1 << (ISA_PNP_selected->ident_bp&7)))
                           ret = ISA_PNP_selected->ident_2nd ? 0xAA : 0x55;
                       else
                           ret = 0xFF;

                       if (++ISA_PNP_selected->ident_2nd >= 2) {
                           ISA_PNP_selected->ident_2nd = 0;
                           ISA_PNP_selected->ident_bp++;
                       }
                   }
               }
               else {
                   ret = 0xFF;
               }
               break;
        case 0x04:  /* read resource data */
               if (ISA_PNP_selected) {
                   if (ISA_PNP_selected->resource_ident < 9)
                       ret = ISA_PNP_selected->ident[ISA_PNP_selected->resource_ident++];              
                   else {
                       /* real-world hardware testing shows that devices act as if there was some fixed block of ROM,
                        * that repeats every 128, 256, 512, or 1024 bytes if you just blindly read from this port. */
                       if (ISA_PNP_selected->resource_data_pos < ISA_PNP_selected->resource_data_len)
                           ret = ISA_PNP_selected->resource_data[ISA_PNP_selected->resource_data_pos++];

                       /* that means that if you read enough bytes the ROM loops back to returning the ident */
                       if (ISA_PNP_selected->resource_data_pos >= ISA_PNP_selected->resource_data_len) {
                           ISA_PNP_selected->resource_data_pos = 0;
                           ISA_PNP_selected->resource_ident = 0;
                       }
                   }
               }
               break;
        case 0x05:  /* read resource status */
               if (ISA_PNP_selected) {
                   /* real-world hardware testing shows that devices act as if there was some fixed block of ROM,
                    * that repeats every 128, 256, 512, or 1024 bytes if you just blindly read from this port.
                    * therefore, there's always a byte to return. */
                   ret = 0x01;  /* TODO: simulate hardware slowness */
               }
               break;
        case 0x06:  /* card select number */
               if (ISA_PNP_selected) ret = ISA_PNP_selected->CSN;
               break;
        case 0x07:  /* logical device number */
               if (ISA_PNP_selected) ret = ISA_PNP_selected->logical_device;
               break;
        default:    /* pass the rest down to the class */
               if (ISA_PNP_selected) ret = ISA_PNP_selected->read(ISA_PNP_CUR_ADDR);
               break;
    }

//  if (1) LOG_MSG("PnP read(%02X) = %02X\n",ISA_PNP_CUR_ADDR,ret);
    return ret;
}

void isapnp_write_port(Bitu port,Bitu val,Bitu /*iolen*/) {
    Bitu i;

    if (port == 0x279) {
//      if (1) LOG_MSG("PnP addr(%02X)\n",val);
        if (val == isa_pnp_init_keystring[ISA_PNP_KEYMATCH]) {
            if (++ISA_PNP_KEYMATCH == 32) {
//              LOG_MSG("ISA PnP key -> going to sleep\n");
                ISA_PNP_CUR_STATE = ISA_PNP_SLEEP;
                ISA_PNP_KEYMATCH = 0;
                for (i=0;i < MAX_ISA_PNP_DEVICES;i++) {
                    if (ISA_PNP_devs[i] != NULL) {
                        ISA_PNP_devs[i]->on_pnp_key();
                    }
                }
            }
        }
        else {
            ISA_PNP_KEYMATCH = 0;
        }

        ISA_PNP_CUR_ADDR = val;
    }
    else if (port == 0xA79) {
//      if (1) LOG_MSG("PnP write(%02X) = %02X\n",ISA_PNP_CUR_ADDR,val);
        switch (ISA_PNP_CUR_ADDR) {
            case 0x00: {    /* RD_DATA */
                unsigned int np = ((val & 0xFF) << 2) | 3;
                if (np != ISA_PNP_WPORT) {
                    if (ISAPNP_PNP_READ_PORT != NULL) {
                        ISAPNP_PNP_READ_PORT = NULL;
                        delete ISAPNP_PNP_READ_PORT;
                    }

                    if (np >= 0x200 && np <= 0x3FF) { /* allowable port I/O range according to spec */
                        LOG_MSG("PNP OS changed I/O read port to 0x%03X (from 0x%03X)\n",np,ISA_PNP_WPORT);

                        ISA_PNP_WPORT = np;
                        ISAPNP_PNP_READ_PORT = new IO_ReadHandleObject;
                        ISAPNP_PNP_READ_PORT->Install(ISA_PNP_WPORT,isapnp_read_port,IO_MB);
                    }
                    else {
                        LOG_MSG("PNP OS I/O read port disabled\n");

                        ISA_PNP_WPORT = 0;
                    }

                    if (ISA_PNP_selected != NULL) {
                        ISA_PNP_selected->ident_bp = 0;
                        ISA_PNP_selected->ident_2nd = 0;
                        ISA_PNP_selected->resource_data_pos = 0;
                    }
                }
            } break;
            case 0x02:  /* config control */
                   if (val & 4) {
                       /* ALL CARDS RESET CSN to 0 */
                       for (i=0;i < MAX_ISA_PNP_DEVICES;i++) {
                           if (ISA_PNP_devs[i] != NULL) {
                               ISA_PNP_devs[i]->CSN = 0;
                           }
                       }
                   }
                   if (val & 2) ISA_PNP_CUR_STATE = ISA_PNP_WAIT_FOR_KEY;
                   if ((val & 1) && ISA_PNP_selected) ISA_PNP_selected->config(val);
                   for (i=0;i < MAX_ISA_PNP_DEVICES;i++) {
                       if (ISA_PNP_devs[i] != NULL) {
                           ISA_PNP_devs[i]->ident_bp = 0;
                           ISA_PNP_devs[i]->ident_2nd = 0;
                           ISA_PNP_devs[i]->resource_data_pos = 0;
                       }
                   }
                   break;
            case 0x03: {    /* wake[CSN] */
                ISA_PNP_selected = NULL;
                for (i=0;ISA_PNP_selected == NULL && i < MAX_ISA_PNP_DEVICES;i++) {
                    if (ISA_PNP_devs[i] == NULL)
                        continue;
                    if (ISA_PNP_devs[i]->CSN == val) {
                        ISA_PNP_selected = ISA_PNP_devs[i];
                        ISA_PNP_selected->wakecsn(val);
                    }
                }
                if (val == 0)
                    ISA_PNP_CUR_STATE = ISA_PNP_ISOLATE;
                else
                    ISA_PNP_CUR_STATE = ISA_PNP_CONFIG;
                } break;
            case 0x06:  /* card select number */
                if (ISA_PNP_selected) ISA_PNP_selected->CSN = val;
                break;
            case 0x07:  /* logical device number */
                if (ISA_PNP_selected) ISA_PNP_selected->select_logical_device(val);
                break;
            default:    /* pass the rest down to the class */
                if (ISA_PNP_selected) ISA_PNP_selected->write(ISA_PNP_CUR_ADDR,val);
                break;
        }
    }
}

static Bitu INT15_Handler(void);

// FIXME: This initializes both APM BIOS and ISA PNP emulation!
//        Need to separate APM BIOS init from ISA PNP init from ISA PNP BIOS init!
//        It might also be appropriate to move this into the BIOS init sequence.
void ISAPNP_Cfg_Reset(Section *sec) {
    (void)sec;//UNUSED
    const Section_prop* section = static_cast<Section_prop*>(control->GetSection("cpu"));

    LOG(LOG_MISC,LOG_DEBUG)("Initializing ISA PnP emulation");

    enable_integration_device = section->Get_bool("integration device");
    enable_integration_device_pnp = section->Get_bool("integration device pnp");
    ISAPNPBIOS = section->Get_bool("isapnpbios");
    APMBIOS = section->Get_bool("apmbios");
    APMBIOS_pnp = section->Get_bool("apmbios pnp");
    APMBIOS_allow_realmode = section->Get_bool("apmbios allow realmode");
    APMBIOS_allow_prot16 = section->Get_bool("apmbios allow 16-bit protected mode");
    APMBIOS_allow_prot32 = section->Get_bool("apmbios allow 32-bit protected mode");

    std::string apmbiosver = section->Get_string("apmbios version");

    /* PC-98 does not have the IBM PC/AT APM BIOS interface */
    if (IS_PC98_ARCH) {
        APMBIOS = false;
        APMBIOS_pnp = false;
    }

    if (apmbiosver == "1.0")
        APM_BIOS_minor_version = 0;
    else if (apmbiosver == "1.1")
        APM_BIOS_minor_version = 1;
    else if (apmbiosver == "1.2")
        APM_BIOS_minor_version = 2;
    else//auto
        APM_BIOS_minor_version = 2;

    /* PC-98 does not have APM.
     * I *think* it has Plug & Play, but probably different from ISA PnP and specific to the C-Bus interface,
     * which I have no information on at this time --J.C. */
    if (IS_PC98_ARCH)
        return;

    LOG(LOG_MISC,LOG_DEBUG)("APM BIOS allow: real=%u pm16=%u pm32=%u version=1.%u",
        APMBIOS_allow_realmode,
        APMBIOS_allow_prot16,
        APMBIOS_allow_prot32,
        APM_BIOS_minor_version);

    if (APMBIOS && (APMBIOS_allow_prot16 || APMBIOS_allow_prot32) && INT15_apm_pmentry == 0) {
        Bitu cb,base;

        /* NTS: This is... kind of a terrible hack. It basically tricks Windows into executing our
         *      INT 15h handler as if the APM entry point. Except that instead of an actual INT 15h
         *      triggering the callback, a FAR CALL triggers the callback instead (CB_RETF not CB_IRET). */
        /* TODO: We should really consider moving the APM BIOS code in INT15_Handler() out into it's
         *       own function, then having the INT15_Handler() call it as well as directing this callback
         *       directly to it. If you think about it, this hack also lets the "APM entry point" invoke
         *       other arbitrary INT 15h calls which is not valid. */

        cb = CALLBACK_Allocate();
        INT15_apm_pmentry = CALLBACK_RealPointer(cb);
        LOG_MSG("Allocated APM BIOS pm entry point at %04x:%04x\n",INT15_apm_pmentry>>16,INT15_apm_pmentry&0xFFFF);
        CALLBACK_Setup(cb,INT15_Handler,CB_RETF,"APM BIOS protected mode entry point");

        /* NTS: Actually INT15_Handler is written to act like an interrupt (IRETF) type callback.
         *      Prior versions hacked this into something that responds by CB_RETF, however some
         *      poking around reveals that CALLBACK_SCF and friends still assume an interrupt
         *      stack, thus, the cause of random crashes in Windows was simply that we were
         *      flipping flag bits in the middle of the return address on the stack. The other
         *      source of random crashes is that the CF/ZF manipulation in INT 15h wasn't making
         *      it's way back to Windows, meaning that when APM BIOS emulation intended to return
         *      an error (by setting CF), Windows didn't get the memo (CF wasn't set on return)
         *      and acted as if the call succeeded, or worse, CF happened to be set on entry and
         *      was never cleared by APM BIOS emulation.
         *
         *      So what we need is:
         *
         *      PUSHF           ; put flags in right place
         *      PUSH    BP      ; dummy FAR pointer
         *      PUSH    BP      ; again
         *      <callback>
         *      POP     BP      ; drop it
         *      POP     BP      ; drop it
         *      POPF
         *      RETF
         *
         *      Then CALLBACK_SCF can work normally this way.
         *
         * NTS: We *still* need to separate APM BIOS calls from the general INT 15H emulation though... */
        base = Real2Phys(INT15_apm_pmentry);
        LOG_MSG("Writing code to %05x\n",(unsigned int)base);

        phys_writeb(base+0x00,0x9C);                             /* pushf */
        phys_writeb(base+0x01,0x55);                             /* push (e)bp */
        phys_writeb(base+0x02,0x55);                             /* push (e)bp */

        phys_writeb(base+0x03,(Bit8u)0xFE);                     //GRP 4
        phys_writeb(base+0x04,(Bit8u)0x38);                     //Extra Callback instruction
        phys_writew(base+0x05,(Bit16u)cb);                      //The immediate word

        phys_writeb(base+0x07,0x5D);                             /* pop (e)bp */
        phys_writeb(base+0x08,0x5D);                             /* pop (e)bp */
        phys_writeb(base+0x09,0x9D);                             /* popf */
        phys_writeb(base+0x0A,0xCB);                             /* retf */
    }
}

void ISAPNP_Cfg_Init() {
    AddVMEventFunction(VM_EVENT_RESET,AddVMEventFunctionFuncPair(ISAPNP_Cfg_Reset));
}

/* the PnP callback registered two entry points. One for real, one for protected mode. */
static Bitu PNPentry_real,PNPentry_prot;

static bool ISAPNP_Verify_BiosSelector(Bitu seg) {
    if (!cpu.pmode || (reg_flags & FLAG_VM)) {
        return (seg == 0xF000);
    } else if (seg == 0)
        return 0;
    else {
#if 1
        /* FIXME: Always return true. But figure out how to ask DOSBox the linear->phys
              mapping to determine whether the segment's base address maps to 0xF0000.
              In the meantime disabling this check makes PnP BIOS emulation work with
              Windows 95 OSR2 which appears to give us a segment mapped to a virtual
              address rather than linearly mapped to 0xF0000 as Windows 95 original
              did. */
        return true;
#else
        Descriptor desc;
        cpu.gdt.GetDescriptor(seg,desc);

        /* TODO: Check desc.Type() to make sure it's a writeable data segment */
        return (desc.GetBase() == 0xF0000);
#endif
    }
}

static bool ISAPNP_CPU_ProtMode() {
    if (!cpu.pmode || (reg_flags & FLAG_VM))
        return 0;

    return 1;
}

static Bitu ISAPNP_xlate_address(Bitu far_ptr) {
    if (!cpu.pmode || (reg_flags & FLAG_VM))
        return Real2Phys(far_ptr);
    else {
        Descriptor desc;
        cpu.gdt.GetDescriptor(far_ptr >> 16,desc);

        /* TODO: Check desc.Type() to make sure it's a writeable data segment */
        return (desc.GetBase() + (far_ptr & 0xFFFF));
    }
}

static const unsigned char ISAPNP_sysdev_Keyboard[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0x3,0x0,0x3), /* PNP0303 IBM Enhanced 101/102 key with PS/2 */
            ISAPNP_TYPE(0x09,0x00,0x00),        /* type: input, keyboard */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x60,0x60,              /* min-max range I/O port */
            0x01,0x01),             /* align=1 length=1 */
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x64,0x64,              /* min-max range I/O port */
            0x01,0x01),             /* align=1 length=1 */
    ISAPNP_IRQ_SINGLE(
            1,                  /* IRQ 1 */
            0x09),                  /* HTE=1 LTL=1 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_Mouse[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xF,0x0,0xE), /* PNP0F0E Microsoft compatible PS/2 */
            ISAPNP_TYPE(0x09,0x02,0x00),        /* type: input, keyboard */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IRQ_SINGLE(
            12,                 /* IRQ 12 */
            0x09),                  /* HTE=1 LTL=1 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_DMA_Controller[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0x2,0x0,0x0), /* PNP0200 AT DMA controller */
            ISAPNP_TYPE(0x08,0x01,0x00),        /* type: input, keyboard */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x00,0x00,              /* min-max range I/O port (DMA channels 0-3) */
            0x10,0x10),             /* align=16 length=16 */
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x81,0x81,              /* min-max range I/O port (DMA page registers) */
            0x01,0x0F),             /* align=1 length=15 */
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0xC0,0xC0,              /* min-max range I/O port (AT DMA channels 4-7) */
            0x20,0x20),             /* align=32 length=32 */
    ISAPNP_DMA_SINGLE(
            4,                  /* DMA 4 */
            0x01),                  /* 8/16-bit transfers, compatible speed */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_PIC[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0x0,0x0,0x0), /* PNP0000 Interrupt controller */
            ISAPNP_TYPE(0x08,0x00,0x01),        /* type: ISA interrupt controller */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x20,0x20,              /* min-max range I/O port */
            0x01,0x02),             /* align=1 length=2 */
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0xA0,0xA0,              /* min-max range I/O port */
            0x01,0x02),             /* align=1 length=2 */
    ISAPNP_IRQ_SINGLE(
            2,                  /* IRQ 2 */
            0x09),                  /* HTE=1 LTL=1 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_Timer[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0x1,0x0,0x0), /* PNP0100 Timer */
            ISAPNP_TYPE(0x08,0x02,0x01),        /* type: ISA timer */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x40,0x40,              /* min-max range I/O port */
            0x04,0x04),             /* align=4 length=4 */
    ISAPNP_IRQ_SINGLE(
            0,                  /* IRQ 0 */
            0x09),                  /* HTE=1 LTL=1 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_RTC[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xB,0x0,0x0), /* PNP0B00 Real-time clock */
            ISAPNP_TYPE(0x08,0x03,0x01),        /* type: ISA real-time clock */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x70,0x70,              /* min-max range I/O port */
            0x01,0x02),             /* align=1 length=2 */
    ISAPNP_IRQ_SINGLE(
            8,                  /* IRQ 8 */
            0x09),                  /* HTE=1 LTL=1 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_PC_Speaker[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0x8,0x0,0x0), /* PNP0800 PC speaker */
            ISAPNP_TYPE(0x04,0x01,0x00),        /* type: PC speaker */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x61,0x61,              /* min-max range I/O port */
            0x01,0x01),             /* align=1 length=1 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_Numeric_Coprocessor[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xC,0x0,0x4), /* PNP0C04 Numeric Coprocessor */
            ISAPNP_TYPE(0x0B,0x80,0x00),        /* type: FPU */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0xF0,0xF0,              /* min-max range I/O port */
            0x10,0x10),             /* align=16 length=16 */
    ISAPNP_IRQ_SINGLE(
            13,                 /* IRQ 13 */
            0x09),                  /* HTE=1 LTL=1 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

static const unsigned char ISAPNP_sysdev_System_Board[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xC,0x0,0x1), /* PNP0C01 System board */
            ISAPNP_TYPE(0x08,0x80,0x00),        /* type: System peripheral, Other */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x24,0x24,              /* min-max range I/O port */
            0x04,0x04),             /* align=4 length=4 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

/* NTS: If some of my late 1990's laptops are any indication, this resource list can be used
 *      as a hint that the motherboard supports Intel EISA/PCI controller DMA registers that
 *      allow ISA DMA to extend to 32-bit addresses instead of being limited to 24-bit */
static const unsigned char ISAPNP_sysdev_General_ISAPNP[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xC,0x0,0x2), /* PNP0C02 General ID for reserving resources */
            ISAPNP_TYPE(0x08,0x80,0x00),        /* type: System peripheral, Other */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_IO_RANGE(
            0x01,                   /* decodes 16-bit ISA addr */
            0x208,0x208,                /* min-max range I/O port */
            0x04,0x04),             /* align=4 length=4 */
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

/* PnP system entry to tell Windows 95 the obvious: That there's an ISA bus present */
/* NTS: Examination of some old laptops of mine shows that these devices do not list any resources,
 *      or at least, an old Toshiba of mine lists the PCI registers 0xCF8-0xCFF as motherboard resources
 *      and defines no resources for the PCI Bus PnP device. */
static const unsigned char ISAPNP_sysdev_ISA_BUS[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xA,0x0,0x0), /* PNP0A00 ISA Bus */
            ISAPNP_TYPE(0x06,0x04,0x00),        /* type: System device, peripheral bus */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

/* PnP system entry to tell Windows 95 the obvious: That there's a PCI bus present */
static const unsigned char ISAPNP_sysdev_PCI_BUS[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xA,0x0,0x3), /* PNP0A03 PCI Bus */
            ISAPNP_TYPE(0x06,0x04,0x00),        /* type: System device, peripheral bus */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

/* to help convince Windows 95 that the APM BIOS is present */
static const unsigned char ISAPNP_sysdev_APM_BIOS[] = {
    ISAPNP_SYSDEV_HEADER(
            ISAPNP_ID('P','N','P',0x0,0xC,0x0,0x5), /* PNP0C05 APM BIOS */
            ISAPNP_TYPE(0x08,0x80,0x00),        /* type: FIXME is this right?? I can't find any examples or documentation */
            0x0001 | 0x0002),           /* can't disable, can't configure */
    /*----------allocated--------*/
    ISAPNP_END,
    /*----------possible--------*/
    ISAPNP_END,
    /*----------compatible--------*/
    ISAPNP_END
};

bool ISAPNP_RegisterSysDev(const unsigned char *raw,Bitu len,bool already) {
    if (ISAPNP_SysDevNodeCount >= MAX_ISA_PNP_SYSDEVNODES)
        return false;

    ISAPNP_SysDevNodes[ISAPNP_SysDevNodeCount] = new ISAPNP_SysDevNode(raw,len,already);
    if (ISAPNP_SysDevNodes[ISAPNP_SysDevNodeCount] == NULL)
        return false;
    
    ISAPNP_SysDevNodeCount++;
    if (ISAPNP_SysDevNodeLargest < (len+3))
        ISAPNP_SysDevNodeLargest = len+3;

    return true;
}

/* ISA PnP function calls have their parameters stored on the stack "C" __cdecl style. Parameters
 * are either int, long, or FAR pointers. Like __cdecl an assembly language implementation pushes
 * the function arguments on the stack BACKWARDS */
static Bitu ISAPNP_Handler(bool protmode /* called from protected mode interface == true */) {
    Bitu arg;
    Bitu func,BiosSelector;

    /* I like how the ISA PnP spec says that the 16-bit entry points (real and protected) are given 16-bit data segments
     * which implies that all segments involved might as well be 16-bit.
     *
     * Right?
     *
     * Well, guess what Windows 95 gives us when calling this entry point:
     *
     *     Segment SS = DS = 0x30  base=0 limit=0xFFFFFFFF
     *       SS:SP = 0x30:0xC138BADF or something like that from within BIOS.VXD
     *
     * Yeah... for a 16-bit code segment call. Right. Typical Microsoft. >:(
     *
     * This might also explain why my early experiments with Bochs always had the perpetual
     * APM BIOS that never worked but was always detected.
     *
     * ------------------------------------------------------------------------
     * Windows 95 OSR2:
     *
     * Windows 95 OSR2 however uses a 16-bit stack (where the stack segment is based somewhere
     * around 0xC1xxxxxx), all we have to do to correctly access it is work through the page tables.
     * This is within spec, but now Microsoft sends us a data segment that is based at virtual address
     * 0xC2xxxxxx, which is why I had to disable the "verify selector" routine */
    arg = SegPhys(ss) + (reg_esp&cpu.stack.mask) + (2*2); /* entry point (real and protected) is 16-bit, expected to RETF (skip CS:IP) */

    if (protmode != ISAPNP_CPU_ProtMode()) {
        //LOG_MSG("ISA PnP %s entry point called from %s. On real BIOSes this would CRASH\n",protmode ? "Protected mode" : "Real mode",
        //  ISAPNP_CPU_ProtMode() ? "Protected mode" : "Real mode");
        reg_ax = 0x84;/* BAD_PARAMETER */
        return 0;
    }

    func = mem_readw(arg);
//  LOG_MSG("PnP prot=%u DS=%04x (base=0x%08lx) SS:ESP=%04x:%04x (base=0x%08lx phys=0x%08lx) function=0x%04x\n",
//      (unsigned int)protmode,(unsigned int)SegValue(ds),(unsigned long)SegPhys(ds),
//      (unsigned int)SegValue(ss),(unsigned int)reg_esp,(unsigned long)SegPhys(ss),
//      (unsigned long)arg,(unsigned int)func);

    /* every function takes the form
     *
     * int __cdecl FAR (*entrypoint)(int Function...);
     *
     * so the first argument on the stack is an int that we read to determine what the caller is asking
     *
     * Dont forget in the real-mode world:
     *    sizeof(int) == 16 bits
     *    sizeof(long) == 32 bits
     */    
    switch (func) {
        case 0: {       /* Get Number of System Nodes */
            /* int __cdecl FAR (*entrypoint)(int Function,unsigned char FAR *NumNodes,unsigned int FAR *NodeSize,unsigned int BiosSelector);
             *                               ^ +0         ^ +2                        ^ +6                       ^ +10                       = 12 */
            Bitu NumNodes_ptr = mem_readd(arg+2);
            Bitu NodeSize_ptr = mem_readd(arg+6);
            BiosSelector = mem_readw(arg+10);

            if (!ISAPNP_Verify_BiosSelector(BiosSelector))
                goto badBiosSelector;

            if (NumNodes_ptr != 0) mem_writeb(ISAPNP_xlate_address(NumNodes_ptr),ISAPNP_SysDevNodeCount);
            if (NodeSize_ptr != 0) mem_writew(ISAPNP_xlate_address(NodeSize_ptr),ISAPNP_SysDevNodeLargest);

            reg_ax = 0x00;/* SUCCESS */
        } break;
        case 1: {       /* Get System Device Node */
            /* int __cdecl FAR (*entrypoint)(int Function,unsigned char FAR *Node,struct DEV_NODE FAR *devNodeBuffer,unsigned int Control,unsigned int BiosSelector);
             *                               ^ +0         ^ +2                    ^ +6                               ^ +10                ^ +12                       = 14 */
            Bitu Node_ptr = mem_readd(arg+2);
            Bitu devNodeBuffer_ptr = mem_readd(arg+6);
            Bitu Control = mem_readw(arg+10);
            BiosSelector = mem_readw(arg+12);
            unsigned char Node;
            Bitu i=0;

            if (!ISAPNP_Verify_BiosSelector(BiosSelector))
                goto badBiosSelector;

            /* control bits 0-1 must be '01' or '10' but not '00' or '11' */
            if (Control == 0 || (Control&3) == 3) {
                LOG_MSG("ISAPNP Get System Device Node: Invalid Control value 0x%04x\n",(int)Control);
                reg_ax = 0x84;/* BAD_PARAMETER */
                break;
            }

            devNodeBuffer_ptr = ISAPNP_xlate_address(devNodeBuffer_ptr);
            Node_ptr = ISAPNP_xlate_address(Node_ptr);
            Node = mem_readb(Node_ptr);
            if (Node >= ISAPNP_SysDevNodeCount) {
                LOG_MSG("ISAPNP Get System Device Node: Invalid Node 0x%02x (max 0x%04x)\n",(int)Node,(int)ISAPNP_SysDevNodeCount);
                reg_ax = 0x84;/* BAD_PARAMETER */
                break;
            }

            const ISAPNP_SysDevNode *nd = ISAPNP_SysDevNodes[Node];

            mem_writew(devNodeBuffer_ptr+0,(Bit16u)(nd->raw_len+3)); /* Length */
            mem_writeb(devNodeBuffer_ptr+2,Node); /* on most PnP BIOS implementations I've seen "handle" is set to the same value as Node */
            for (i=0;i < (Bitu)nd->raw_len;i++)
                mem_writeb(devNodeBuffer_ptr+i+3,nd->raw[i]);

//          LOG_MSG("ISAPNP OS asked for Node 0x%02x\n",Node);

            if (++Node >= ISAPNP_SysDevNodeCount) Node = 0xFF; /* no more nodes */
            mem_writeb(Node_ptr,Node);

            reg_ax = 0x00;/* SUCCESS */
        } break;
        case 4: {       /* Send Message */
            /* int __cdecl FAR (*entrypoint)(int Function,unsigned int Message,unsigned int BiosSelector);
             *                               ^ +0         ^ +2                 ^ +4                        = 6 */
            Bitu Message = mem_readw(arg+2);
            BiosSelector = mem_readw(arg+4);

            if (!ISAPNP_Verify_BiosSelector(BiosSelector))
                goto badBiosSelector;

            switch (Message) {
                case 0x41:  /* POWER_OFF */
                    LOG_MSG("Plug & Play OS requested power off.\n");
                    reg_ax = 0;
                    throw 1;    /* NTS: Based on the Reboot handler code, causes DOSBox to cleanly shutdown and exit */
                    break;
                case 0x42:  /* PNP_OS_ACTIVE */
                    LOG_MSG("Plug & Play OS reports itself active\n");
                    reg_ax = 0;
                    break;
                case 0x43:  /* PNP_OS_INACTIVE */
                    LOG_MSG("Plug & Play OS reports itself inactive\n");
                    reg_ax = 0;
                    break;
                default:
                    LOG_MSG("Unknown ISA PnP message 0x%04x\n",(int)Message);
                    reg_ax = 0x82;/* FUNCTION_NOT_SUPPORTED */
                    break;
            }
        } break;
        case 0x40: {        /* Get PnP ISA configuration */
            /* int __cdecl FAR (*entrypoint)(int Function,unsigned char far *struct,unsigned int BiosSelector);
             *                               ^ +0         ^ +2                      ^ +6                        = 8 */
            Bitu struct_ptr = mem_readd(arg+2);
            BiosSelector = mem_readw(arg+6);

            if (!ISAPNP_Verify_BiosSelector(BiosSelector))
                goto badBiosSelector;

            /* struct isapnp_pnp_isa_cfg {
                 uint8_t    revision;
                 uint8_t    total_csn;
                 uint16_t   isa_pnp_port;
                 uint16_t   reserved;
             }; */

            if (struct_ptr != 0) {
                Bitu ph = ISAPNP_xlate_address(struct_ptr);
                mem_writeb(ph+0,0x01);      /* ->revision = 0x01 */
                mem_writeb(ph+1,ISA_PNP_devnext); /* ->total_csn */
                mem_writew(ph+2,ISA_PNP_WPORT_BIOS);    /* ->isa_pnp_port */
                mem_writew(ph+4,0);     /* ->reserved */
            }

            reg_ax = 0x00;/* SUCCESS */
        } break;
        default:
            //LOG_MSG("Unsupported ISA PnP function 0x%04x\n",func);
            reg_ax = 0x82;/* FUNCTION_NOT_SUPPORTED */
            break;
    }

    return 0;
badBiosSelector:
    /* return an error. remind the user (possible developer) how lucky he is, a real
     * BIOS implementation would CRASH when misused like this */
    LOG_MSG("ISA PnP function 0x%04x called with incorrect BiosSelector parameter 0x%04x\n",(int)func,(int)BiosSelector);
    LOG_MSG(" > STACK %04X %04X %04X %04X %04X %04X %04X %04X\n",
        mem_readw(arg),     mem_readw(arg+2),   mem_readw(arg+4),   mem_readw(arg+6),
        mem_readw(arg+8),   mem_readw(arg+10),  mem_readw(arg+12),  mem_readw(arg+14));

    reg_ax = 0x84;/* BAD_PARAMETER */
    return 0;
}

static Bitu ISAPNP_Handler_PM(void) {
    return ISAPNP_Handler(true);
}

static Bitu ISAPNP_Handler_RM(void) {
    return ISAPNP_Handler(false);
}

static Bitu INT70_Handler(void) {
    /* Acknowledge irq with cmos */
    IO_Write(0x70,0xc);
    IO_Read(0x71);
    if (mem_readb(BIOS_WAIT_FLAG_ACTIVE)) {
        Bit32u count=mem_readd(BIOS_WAIT_FLAG_COUNT);
        if (count>997) {
            mem_writed(BIOS_WAIT_FLAG_COUNT,count-997);
        } else {
            mem_writed(BIOS_WAIT_FLAG_COUNT,0);
            PhysPt where=Real2Phys(mem_readd(BIOS_WAIT_FLAG_POINTER));
            mem_writeb(where,mem_readb(where)|0x80);
            mem_writeb(BIOS_WAIT_FLAG_ACTIVE,0);
            mem_writed(BIOS_WAIT_FLAG_POINTER,RealMake(0,BIOS_WAIT_FLAG_TEMP));
            IO_Write(0x70,0xb);
            IO_Write(0x71,IO_Read(0x71)&~0x40);
        }
    } 
    /* Signal EOI to both pics */
    IO_Write(0xa0,0x20);
    IO_Write(0x20,0x20);
    return 0;
}

CALLBACK_HandlerObject* tandy_DAC_callback[2];
static struct {
    Bit16u port;
    Bit8u irq;
    Bit8u dma;
} tandy_sb;
static struct {
    Bit16u port;
    Bit8u irq;
    Bit8u dma;
} tandy_dac;

static bool Tandy_InitializeSB() {
    /* see if soundblaster module available and at what port/IRQ/DMA */
    Bitu sbport, sbirq, sbdma;
    if (SB_Get_Address(sbport, sbirq, sbdma)) {
        tandy_sb.port=(Bit16u)(sbport&0xffff);
        tandy_sb.irq =(Bit8u)(sbirq&0xff);
        tandy_sb.dma =(Bit8u)(sbdma&0xff);
        return true;
    } else {
        /* no soundblaster accessible, disable Tandy DAC */
        tandy_sb.port=0;
        return false;
    }
}

static bool Tandy_InitializeTS() {
    /* see if Tandy DAC module available and at what port/IRQ/DMA */
    Bitu tsport, tsirq, tsdma;
    if (TS_Get_Address(tsport, tsirq, tsdma)) {
        tandy_dac.port=(Bit16u)(tsport&0xffff);
        tandy_dac.irq =(Bit8u)(tsirq&0xff);
        tandy_dac.dma =(Bit8u)(tsdma&0xff);
        return true;
    } else {
        /* no Tandy DAC accessible */
        tandy_dac.port=0;
        return false;
    }
}

/* check if Tandy DAC is still playing */
static bool Tandy_TransferInProgress(void) {
    if (real_readw(0x40,0xd0)) return true;         /* not yet done */
    if (real_readb(0x40,0xd4)==0xff) return false;  /* still in init-state */

    Bit8u tandy_dma = 1;
    if (tandy_sb.port) tandy_dma = tandy_sb.dma;
    else if (tandy_dac.port) tandy_dma = tandy_dac.dma;

    IO_Write(0x0c,0x00);
    Bit16u datalen = (IO_ReadB(tandy_dma * 2 + 1)) + (IO_ReadB(tandy_dma * 2 + 1) << 8);
    if (datalen==0xffff) return false;  /* no DMA transfer */
    else if ((datalen<0x10) && (real_readb(0x40,0xd4)==0x0f) && (real_readw(0x40,0xd2)==0x1c)) {
        /* stop already requested */
        return false;
    }
    return true;
}

static void Tandy_SetupTransfer(PhysPt bufpt,bool isplayback) {
    Bitu length=real_readw(0x40,0xd0);
    if (length==0) return;  /* nothing to do... */

    if ((tandy_sb.port==0) && (tandy_dac.port==0)) return;

    Bit8u tandy_irq = 7;
    if (tandy_sb.port) tandy_irq = tandy_sb.irq;
    else if (tandy_dac.port) tandy_irq = tandy_dac.irq;
    Bit8u tandy_irq_vector = tandy_irq;
    if (tandy_irq_vector<8) tandy_irq_vector += 8;
    else tandy_irq_vector += (0x70-8);

    /* revector IRQ-handler if necessary */
    RealPt current_irq=RealGetVec(tandy_irq_vector);
    if (current_irq!=tandy_DAC_callback[0]->Get_RealPointer()) {
        real_writed(0x40,0xd6,current_irq);
        RealSetVec(tandy_irq_vector,tandy_DAC_callback[0]->Get_RealPointer());
    }

    Bit8u tandy_dma = 1;
    if (tandy_sb.port) tandy_dma = tandy_sb.dma;
    else if (tandy_dac.port) tandy_dma = tandy_dac.dma;

    if (tandy_sb.port) {
        IO_Write(tandy_sb.port+0xcu,0xd0);               /* stop DMA transfer */
        IO_Write(0x21,IO_Read(0x21)&(~(1u<<tandy_irq))); /* unmask IRQ */
        IO_Write(tandy_sb.port+0xcu,0xd1);               /* turn speaker on */
    } else {
        IO_Write(tandy_dac.port,IO_Read(tandy_dac.port)&0x60);  /* disable DAC */
        IO_Write(0x21,IO_Read(0x21)&(~(1u<<tandy_irq)));         /* unmask IRQ */
    }

    IO_Write(0x0a,0x04|tandy_dma);  /* mask DMA channel */
    IO_Write(0x0c,0x00);            /* clear DMA flipflop */
    if (isplayback) IO_Write(0x0b,0x48|tandy_dma);
    else IO_Write(0x0b,0x44|tandy_dma);
    /* set physical address of buffer */
    Bit8u bufpage=(Bit8u)((bufpt>>16u)&0xff);
    IO_Write(tandy_dma*2u,(Bit8u)(bufpt&0xff));
    IO_Write(tandy_dma*2u,(Bit8u)((bufpt>>8u)&0xff));
    switch (tandy_dma) {
        case 0: IO_Write(0x87,bufpage); break;
        case 1: IO_Write(0x83,bufpage); break;
        case 2: IO_Write(0x81,bufpage); break;
        case 3: IO_Write(0x82,bufpage); break;
    }
    real_writeb(0x40,0xd4,bufpage);

    /* calculate transfer size (respects segment boundaries) */
    Bit32u tlength=length;
    if (tlength+(bufpt&0xffff)>0x10000) tlength=0x10000-(bufpt&0xffff);
    real_writew(0x40,0xd0,(Bit16u)(length-tlength));    /* remaining buffer length */
    tlength--;

    /* set transfer size */
    IO_Write(tandy_dma*2u+1u,(Bit8u)(tlength&0xffu));
    IO_Write(tandy_dma*2u+1u,(Bit8u)((tlength>>8u)&0xffu));

    Bit16u delay=(Bit16u)(real_readw(0x40,0xd2)&0xfff);
    Bit8u amplitude=(Bit8u)(((unsigned int)real_readw(0x40,0xd2)>>13u)&0x7u);
    if (tandy_sb.port) {
        IO_Write(0x0a,tandy_dma);   /* enable DMA channel */
        /* set frequency */
        IO_Write(tandy_sb.port+0xcu,0x40);
        IO_Write(tandy_sb.port+0xcu,256u - delay*100u/358u);
        /* set playback type to 8bit */
        if (isplayback) IO_Write(tandy_sb.port+0xcu,0x14u);
        else IO_Write(tandy_sb.port+0xcu,0x24u);
        /* set transfer size */
        IO_Write(tandy_sb.port+0xcu,(Bit8u)(tlength&0xffu));
        IO_Write(tandy_sb.port+0xcu,(Bit8u)((tlength>>8)&0xffu));
    } else {
        if (isplayback) IO_Write(tandy_dac.port,(IO_Read(tandy_dac.port)&0x7cu) | 0x03u);
        else IO_Write(tandy_dac.port,(IO_Read(tandy_dac.port)&0x7cu) | 0x02u);
        IO_Write(tandy_dac.port+2u,(Bit8u)(delay&0xffu));
        IO_Write(tandy_dac.port+3u,(Bit8u)((((unsigned int)delay>>8u)&0xfu) | ((unsigned int)amplitude<<5u)));
        if (isplayback) IO_Write(tandy_dac.port,(IO_Read(tandy_dac.port)&0x7cu) | 0x1fu);
        else IO_Write(tandy_dac.port,(IO_Read(tandy_dac.port)&0x7c) | 0x1e);
        IO_Write(0x0a,tandy_dma);   /* enable DMA channel */
    }

    if (!isplayback) {
        /* mark transfer as recording operation */
        real_writew(0x40,0xd2,(Bit16u)(delay|0x1000));
    }
}

static Bitu IRQ_TandyDAC(void) {
    if (tandy_dac.port) {
        IO_Read(tandy_dac.port);
    }
    if (real_readw(0x40,0xd0)) {    /* play/record next buffer */
        /* acknowledge IRQ */
        IO_Write(0x20,0x20);
        if (tandy_sb.port) {
            IO_Read(tandy_sb.port+0xeu);
        }

        /* buffer starts at the next page */
        Bit8u npage=real_readb(0x40,0xd4)+1u;
        real_writeb(0x40,0xd4,npage);

        Bitu rb=real_readb(0x40,0xd3);
        if (rb&0x10) {
            /* start recording */
            real_writeb(0x40,0xd3,rb&0xefu);
            Tandy_SetupTransfer((unsigned int)npage<<16u,false);
        } else {
            /* start playback */
            Tandy_SetupTransfer((unsigned int)npage<<16u,true);
        }
    } else {    /* playing/recording is finished */
        Bit8u tandy_irq = 7u;
        if (tandy_sb.port) tandy_irq = tandy_sb.irq;
        else if (tandy_dac.port) tandy_irq = tandy_dac.irq;
        Bit8u tandy_irq_vector = tandy_irq;
        if (tandy_irq_vector<8u) tandy_irq_vector += 8u;
        else tandy_irq_vector += (0x70u-8u);

        RealSetVec(tandy_irq_vector,real_readd(0x40,0xd6));

        /* turn off speaker and acknowledge soundblaster IRQ */
        if (tandy_sb.port) {
            IO_Write(tandy_sb.port+0xcu,0xd3u);
            IO_Read(tandy_sb.port+0xeu);
        }

        /* issue BIOS tandy sound device busy callout */
        SegSet16(cs, RealSeg(tandy_DAC_callback[1]->Get_RealPointer()));
        reg_ip = RealOff(tandy_DAC_callback[1]->Get_RealPointer());
    }
    return CBRET_NONE;
}

static void TandyDAC_Handler(Bit8u tfunction) {
    if ((!tandy_sb.port) && (!tandy_dac.port)) return;
    switch (tfunction) {
    case 0x81:  /* Tandy sound system check */
        if (tandy_dac.port) {
            reg_ax=tandy_dac.port;
        } else {
            reg_ax=0xc4;
        }
        CALLBACK_SCF(Tandy_TransferInProgress());
        break;
    case 0x82:  /* Tandy sound system start recording */
    case 0x83:  /* Tandy sound system start playback */
        if (Tandy_TransferInProgress()) {
            /* cannot play yet as the last transfer isn't finished yet */
            reg_ah=0x00;
            CALLBACK_SCF(true);
            break;
        }
        /* store buffer length */
        real_writew(0x40,0xd0,reg_cx);
        /* store delay and volume */
        real_writew(0x40,0xd2,(reg_dx&0xfff)|((reg_al&7)<<13));
        Tandy_SetupTransfer(PhysMake(SegValue(es),reg_bx),reg_ah==0x83);
        reg_ah=0x00;
        CALLBACK_SCF(false);
        break;
    case 0x84:  /* Tandy sound system stop playing */
        reg_ah=0x00;

        /* setup for a small buffer with silence */
        real_writew(0x40,0xd0,0x0a);
        real_writew(0x40,0xd2,0x1c);
        Tandy_SetupTransfer(PhysMake(0xf000,0xa084),true);
        CALLBACK_SCF(false);
        break;
    case 0x85:  /* Tandy sound system reset */
        if (tandy_dac.port) {
            IO_Write(tandy_dac.port,(Bit8u)(IO_Read(tandy_dac.port)&0xe0));
        }
        reg_ah=0x00;
        CALLBACK_SCF(false);
        break;
    }
}

extern bool date_host_forced;
static Bit8u ReadCmosByte (Bitu index) {
    IO_Write(0x70, index);
    return IO_Read(0x71);
}

static void WriteCmosByte (Bitu index, Bitu val) {
    IO_Write(0x70, index);
    IO_Write(0x71, val);
}

static bool RtcUpdateDone () {
    while ((ReadCmosByte(0x0a) & 0x80) != 0) CALLBACK_Idle();
    return true;            // cannot fail in DOSbox
}

static void InitRtc () {
    WriteCmosByte(0x0a, 0x26);      // default value (32768Hz, 1024Hz)

    // leave bits 6 (pirq), 5 (airq), 0 (dst) untouched
    // reset bits 7 (freeze), 4 (uirq), 3 (sqw), 2 (bcd)
    // set bit 1 (24h)
    WriteCmosByte(0x0b, (ReadCmosByte(0x0b) & 0x61u) | 0x02u);

    ReadCmosByte(0x0c);             // clear any bits set
}

static Bitu INT1A_Handler(void) {
    CALLBACK_SIF(true);
    switch (reg_ah) {
    case 0x00:  /* Get System time */
        {
            Bit32u ticks=mem_readd(BIOS_TIMER);
            reg_al=mem_readb(BIOS_24_HOURS_FLAG);
            mem_writeb(BIOS_24_HOURS_FLAG,0); // reset the "flag"
            reg_cx=(Bit16u)(ticks >> 16u);
            reg_dx=(Bit16u)(ticks & 0xffff);
            break;
        }
    case 0x01:  /* Set System time */
        mem_writed(BIOS_TIMER,((unsigned int)reg_cx<<16u)|reg_dx);
        break;
    case 0x02:  /* GET REAL-TIME CLOCK TIME (AT,XT286,PS) */
        if(date_host_forced) {
            InitRtc();                          // make sure BCD and no am/pm
            if (RtcUpdateDone()) {              // make sure it's safe to read
                reg_ch = ReadCmosByte(0x04);    // hours
                reg_cl = ReadCmosByte(0x02);    // minutes
                reg_dh = ReadCmosByte(0x00);    // seconds
                reg_dl = ReadCmosByte(0x0b) & 0x01; // daylight saving time
            }
            CALLBACK_SCF(false);
            break;
        }
        IO_Write(0x70,0x04);        //Hours
        reg_ch=IO_Read(0x71);
        IO_Write(0x70,0x02);        //Minutes
        reg_cl=IO_Read(0x71);
        IO_Write(0x70,0x00);        //Seconds
        reg_dh=IO_Read(0x71);
        reg_dl=0;           //Daylight saving disabled
        CALLBACK_SCF(false);
        break;
    case 0x03:  // set RTC time
        if(date_host_forced) {
            InitRtc();                          // make sure BCD and no am/pm
            WriteCmosByte(0x0b, ReadCmosByte(0x0b) | 0x80u);     // prohibit updates
            WriteCmosByte(0x04, reg_ch);        // hours
            WriteCmosByte(0x02, reg_cl);        // minutes
            WriteCmosByte(0x00, reg_dh);        // seconds
            WriteCmosByte(0x0b, (ReadCmosByte(0x0b) & 0x7eu) | (reg_dh & 0x01u)); // dst + implicitly allow updates
        }
        break;
    case 0x04:  /* GET REAL-TIME ClOCK DATE  (AT,XT286,PS) */
        if(date_host_forced) {
            InitRtc();                          // make sure BCD and no am/pm
            if (RtcUpdateDone()) {              // make sure it's safe to read
                reg_ch = ReadCmosByte(0x32);    // century
                reg_cl = ReadCmosByte(0x09);    // year
                reg_dh = ReadCmosByte(0x08);    // month
                reg_dl = ReadCmosByte(0x07);    // day
            }
            CALLBACK_SCF(false);
            break;
        }
        IO_Write(0x70,0x32);        //Centuries
        reg_ch=IO_Read(0x71);
        IO_Write(0x70,0x09);        //Years
        reg_cl=IO_Read(0x71);
        IO_Write(0x70,0x08);        //Months
        reg_dh=IO_Read(0x71);
        IO_Write(0x70,0x07);        //Days
        reg_dl=IO_Read(0x71);
        CALLBACK_SCF(false);
        break;
    case 0x05:  // set RTC date
        if(date_host_forced) {
            InitRtc();                          // make sure BCD and no am/pm
            WriteCmosByte(0x0b, ReadCmosByte(0x0b) | 0x80);     // prohibit updates
            WriteCmosByte(0x32, reg_ch);    // century
            WriteCmosByte(0x09, reg_cl);    // year
            WriteCmosByte(0x08, reg_dh);    // month
            WriteCmosByte(0x07, reg_dl);    // day
            WriteCmosByte(0x0b, (ReadCmosByte(0x0b) & 0x7f));   // allow updates
        }
        break;
    case 0x80:  /* Pcjr Setup Sound Multiplexer */
        LOG(LOG_BIOS,LOG_ERROR)("INT1A:80:Setup tandy sound multiplexer to %d",reg_al);
        break;
    case 0x81:  /* Tandy sound system check */
    case 0x82:  /* Tandy sound system start recording */
    case 0x83:  /* Tandy sound system start playback */
    case 0x84:  /* Tandy sound system stop playing */
    case 0x85:  /* Tandy sound system reset */
        TandyDAC_Handler(reg_ah);
        break;
    case 0xb1:      /* PCI Bios Calls */
        if (pcibus_enable) {
            LOG(LOG_BIOS,LOG_WARN)("INT1A:PCI bios call %2X",reg_al);
            switch (reg_al) {
                case 0x01:  // installation check
                    if (PCI_IsInitialized()) {
                        reg_ah=0x00;
                        reg_al=0x01;    // cfg space mechanism 1 supported
                        reg_bx=0x0210;  // ver 2.10
                        reg_cx=0x0000;  // only one PCI bus
                        reg_edx=0x20494350;
                        reg_edi=PCI_GetPModeInterface();
                        CALLBACK_SCF(false);
                    } else {
                        CALLBACK_SCF(true);
                    }
                    break;
                case 0x02: {    // find device
                    Bitu devnr=0u;
                    Bitu count=0x100u;
                    Bit32u devicetag=((unsigned int)reg_cx<<16u)|reg_dx;
                    Bits found=-1;
                    for (Bitu i=0; i<=count; i++) {
                        IO_WriteD(0xcf8,0x80000000u|(i<<8u)); // query unique device/subdevice entries
                        if (IO_ReadD(0xcfc)==devicetag) {
                            if (devnr==reg_si) {
                                found=(Bits)i;
                                break;
                            } else {
                                // device found, but not the SIth device
                                devnr++;
                            }
                        }
                    }
                    if (found>=0) {
                        reg_ah=0x00;
                        reg_bh=0x00;    // bus 0
                        reg_bl=(Bit8u)(found&0xff);
                        CALLBACK_SCF(false);
                    } else {
                        reg_ah=0x86;    // device not found
                        CALLBACK_SCF(true);
                    }
                    }
                    break;
                case 0x03: {    // find device by class code
                    Bitu devnr=0;
                    Bitu count=0x100u;
                    Bit32u classtag=reg_ecx&0xffffffu;
                    Bits found=-1;
                    for (Bitu i=0; i<=count; i++) {
                        IO_WriteD(0xcf8,0x80000000u|(i<<8u)); // query unique device/subdevice entries
                        if (IO_ReadD(0xcfc)!=0xffffffffu) {
                            IO_WriteD(0xcf8,0x80000000u|(i<<8u)|0x08u);
                            if ((IO_ReadD(0xcfc)>>8u)==classtag) {
                                if (devnr==reg_si) {
                                    found=(Bits)i;
                                    break;
                                } else {
                                    // device found, but not the SIth device
                                    devnr++;
                                }
                            }
                        }
                    }
                    if (found>=0) {
                        reg_ah=0x00;
                        reg_bh=0x00;    // bus 0
                        reg_bl=(Bit8u)found & 0xffu;
                        CALLBACK_SCF(false);
                    } else {
                        reg_ah=0x86;    // device not found
                        CALLBACK_SCF(true);
                    }
                    }
                    break;
                case 0x08:  // read configuration byte
                    IO_WriteD(0xcf8,0x80000000u|((unsigned int)reg_bx<<8u)|(reg_di&0xfcu));
                    reg_cl=IO_ReadB(0xcfc+(reg_di&3u));
                    CALLBACK_SCF(false);
                    reg_ah=0x00;
                    break;
                case 0x09:  // read configuration word
                    IO_WriteD(0xcf8,0x80000000u|((unsigned int)reg_bx<<8u)|(reg_di&0xfcu));
                    reg_cx=IO_ReadW(0xcfc+(reg_di&2u));
                    CALLBACK_SCF(false);
                    reg_ah=0x00;
                    break;
                case 0x0a:  // read configuration dword
                    IO_WriteD(0xcf8,0x80000000u|((unsigned int)reg_bx<<8u)|(reg_di&0xfcu));
                    reg_ecx=IO_ReadD(0xcfc+(reg_di&3u));
                    CALLBACK_SCF(false);
                    reg_ah=0x00;
                    break;
                case 0x0b:  // write configuration byte
                    IO_WriteD(0xcf8,0x80000000u|((unsigned int)reg_bx<<8u)|(reg_di&0xfcu));
                    IO_WriteB(0xcfc+(reg_di&3u),reg_cl);
                    CALLBACK_SCF(false);
                    reg_ah=0x00;
                    break;
                case 0x0c:  // write configuration word
                    IO_WriteD(0xcf8,0x80000000u|((unsigned int)reg_bx<<8u)|(reg_di&0xfcu));
                    IO_WriteW(0xcfc+(reg_di&2u),reg_cx);
                    CALLBACK_SCF(false);
                    reg_ah=0x00;
                    break;
                case 0x0d:  // write configuration dword
                    IO_WriteD(0xcf8,0x80000000u|((unsigned int)reg_bx<<8u)|(reg_di&0xfcu));
                    IO_WriteD(0xcfc+((unsigned int)reg_di&3u),reg_ecx);
                    CALLBACK_SCF(false);
                    reg_ah=0x00;
                    break;
                default:
                    LOG(LOG_BIOS,LOG_ERROR)("INT1A:PCI BIOS: unknown function %x (%x %x %x)",
                        reg_ax,reg_bx,reg_cx,reg_dx);
                    CALLBACK_SCF(true);
                    break;
            }
        }
        else {
            CALLBACK_SCF(true);
        }
        break;
    default:
        LOG(LOG_BIOS,LOG_ERROR)("INT1A:Undefined call %2X",reg_ah);
    }
    return CBRET_NONE;
}   

bool INT16_get_key(Bit16u &code);
bool INT16_peek_key(Bit16u &code);

extern uint8_t                     GDC_display_plane;
extern uint8_t                     GDC_display_plane_pending;
extern bool                        GDC_vsync_interrupt;

unsigned char prev_pc98_mode42 = 0;

unsigned char pc98_function_row_mode = 0;

const char *pc98_func_key_default[10] = {
    " C1  ",
    " CU  ",
    " CA  ",
    " S1  ",
    " SU  ",

    "VOID ",
    "NWL  ",
    "INS  ",
    "REP  ",
    " ^Z  "
};

const char pc98_func_key_escapes_default[10][3] = {
    {0x1B,0x53,0},          // F1
    {0x1B,0x54,0},          // F2
    {0x1B,0x55,0},          // F3
    {0x1B,0x56,0},          // F4
    {0x1B,0x57,0},          // F5
    {0x1B,0x45,0},          // F6
    {0x1B,0x4A,0},          // F7
    {0x1B,0x50,0},          // F8
    {0x1B,0x51,0},          // F9
    {0x1B,0x5A,0}           // F10
};

const char pc98_editor_key_escapes_default[11][3] = {
    {0},                    // ROLL UP                  0x36
    {0},                    // ROLL DOWN                0x37
    {0x1B,0x50,0},          // INS                      0x38
    {0x1B,0x44,0},          // DEL                      0x39
    {0x0B,0},               // UP ARROW                 0x3A
    {0x08,0},               // LEFT ARROW               0x3B
    {0x0C,0},               // RIGHT ARROW              0x3C
    {0x0A,0},               // DOWN ARROW               0x3D
    {0},                    // HOME/CLR                 0x3E
    {0},                    // HELP                     0x3F
    {0}                     // KEYPAD -                 0x40
};

// shortcuts offered by SHIFT F1-F10. You can bring this onscreen using CTRL+F7. This row shows '*' in col 2.
// The text displayed onscreen is obviously just the first 6 chars of the shortcut text.
const char *pc98_shcut_key_defaults[10] = {
    "dir a:\x0D",
    "dir b:\x0D",
    "copy ",
    "del ",
    "ren ",

    "chkdsk a:\x0D",
    "chkdsk b:\x0D",
    "type ",
    "date\x0D",
    "time\x0D"
};

#pragma pack(push,1)
struct pc98_func_key_shortcut_def {
    unsigned char           length;         /* +0x00  length of text */
    unsigned char           shortcut[0x0E]; /* +0x01  Shortcut text to insert into CON device */
    unsigned char           pad;            /* +0x0F  always NUL */

    std::string getShortcutText(void) const {
        std::string ret;
        unsigned int i;

        /* Whether a shortcut or escape (0xFE or not) the first 6 chars are displayed always */
        /* TODO: Strings for display are expected to display as Shift-JIS, convert to UTF-8 for display on host */
        for (i=0;i < 0x0E;i++) {
            if (shortcut[i] == 0u)
                break;
            else if (shortcut[i] == 0x1B) {
                ret += "<ESC>";
            }
            else if (shortcut[i] > 0x7Fu || shortcut[i] < 32u) /* 0xFE is invisible on real hardware */
                ret += ' ';
            else
                ret += (char)shortcut[i];
        }

        return ret;
    }

    std::string getDisplayText(void) const {
        unsigned int i;
        char tmp[8];

        /* Whether a shortcut or escape (0xFE or not) the first 6 chars are displayed always */
        /* TODO: Strings for display are expected to display as Shift-JIS, convert to UTF-8 for display on host */
        for (i=0;i < 6;i++) {
            if (shortcut[i] == 0u)
                break;
            else if (shortcut[i] > 0x7Fu || shortcut[i] < 32u) /* 0xFE is invisible on real hardware */
                tmp[i] = ' ';
            else
                tmp[i] = (char)shortcut[i];
        }
        tmp[i] = 0;

        return tmp;
    }

    std::string debugToString(void) const {
        std::string ret;
        char tmp[512];

        if (length == 0)
            return "(none)";

        if (shortcut[0] == 0xFE) {
            sprintf(tmp,"disp=\"%s\" ",getDisplayText().c_str());
            ret += tmp;

            ret += "dispraw={ ";
            for (unsigned int i=0;i < 6;i++) {
                sprintf(tmp,"%02x ",shortcut[i]);
                ret += tmp;
            }
            ret += "} ";

            ret += "esc={ ";
            for (unsigned int i=6;i < length;i++) {
                sprintf(tmp,"%02x ",shortcut[i]);
                ret += tmp;
            }
            ret += "}";
        }
        else {
            sprintf(tmp,"text=\"%s\" ",getShortcutText().c_str());
            ret += tmp;

            ret += "esc={ ";
            for (unsigned int i=0;i < length;i++) {
                sprintf(tmp,"%02x ",shortcut[i]);
                ret += tmp;
            }
            ret += "}";
        }

        return ret;
    }

    // set shortcut.
    // usually a direct string to insert.
    void set_shortcut(const char *str) {
        unsigned int i=0;
        char c;

        while (i < 0x0E && (c = *str++) != 0) shortcut[i++] = (unsigned char)c;
        length = i;

        while (i < 0x0E) shortcut[i++] = 0;
    }

    // set text and escape code. text does NOT include the leading 0xFE char.
    void set_text_and_escape(const char *text,const char *escape) {
        unsigned int i=1;
        char c;

        // this is based on observed MS-DOS behavior on PC-98.
        // the length byte covers both the display text and escape code (sum of the two).
        // the first byte of the shortcut is 0xFE which apparently means the next 5 chars
        // are text to display. The 0xFE is copied as-is to the display when rendered.
        // 0xFE in the CG ROM is a blank space.
        shortcut[0] = 0xFE;
        while (i < 6 && (c = *text++) != 0) shortcut[i++] = (unsigned char)c;
        while (i < 6) shortcut[i++] = ' ';

        while (i < 0x0E && (c = *escape++) != 0) shortcut[i++] = (unsigned char)c;
        length = i;
        while (i < 0x0E) shortcut[i++] = 0;
    }
};                                          /* =0x10 */
#pragma pack(pop)

struct pc98_func_key_shortcut_def   pc98_func_key[10];                  /* F1-F10 */
struct pc98_func_key_shortcut_def   pc98_vfunc_key[5];                  /* VF1-VF5 */
struct pc98_func_key_shortcut_def   pc98_func_key_shortcut[10];         /* Shift+F1 - Shift-F10 */
struct pc98_func_key_shortcut_def   pc98_vfunc_key_shortcut[5];         /* Shift+VF1 - Shift-VF5 */
struct pc98_func_key_shortcut_def   pc98_func_key_ctrl[10];             /* Control+F1 - Control-F10 */
struct pc98_func_key_shortcut_def   pc98_vfunc_key_ctrl[5];             /* Control+VF1 - Control-VF5 */
struct pc98_func_key_shortcut_def   pc98_editor_key_escapes[11];        /* Editor keys */

// FIXME: This is STUPID. Cleanup is needed in order to properly use std::min without causing grief.
#ifdef _MSC_VER
# define MIN(a,b) ((a) < (b) ? (a) : (b))
# define MAX(a,b) ((a) > (b) ? (a) : (b))
#else
# define MIN(a,b) std::min(a,b)
# define MAX(a,b) std::max(a,b)
#endif

void PC98_GetFuncKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i,const struct pc98_func_key_shortcut_def *keylist) {
    if (i >= 1 && i <= 10) {
        const pc98_func_key_shortcut_def &def = keylist[i-1u];
        unsigned int j=0,o=0;

        /* if the shortcut starts with 0xFE then the next 5 chars are intended for display only
         * and the shortcut starts after that. Else the entire string is stuffed into the CON
         * device. */
        if (def.shortcut[0] == 0xFE)
            j = 6;

        while (j < MIN(0x0Eu,(unsigned int)def.length))
            buf[o++] = def.shortcut[j++];

        len = (size_t)o;
        buf[o] = 0;
    }
    else {
        len = 0;
        buf[0] = 0;
    }
}

void PC98_GetEditorKeyEscape(size_t &len,unsigned char buf[16],const unsigned int scan) {
    if (scan >= 0x36 && scan <= 0x40) {
        const pc98_func_key_shortcut_def &def = pc98_editor_key_escapes[scan-0x36];
        unsigned int j=0,o=0;

        /* if the shortcut starts with 0xFE then the next 5 chars are intended for display only
         * and the shortcut starts after that. Else the entire string is stuffed into the CON
         * device. */
        if (def.shortcut[0] == 0xFE)
            j = 6;

        while (j < MIN(0x0Eu,(unsigned int)def.length))
            buf[o++] = def.shortcut[j++];

        len = (size_t)o;
        buf[o] = 0;
    }
    else {
        len = 0;
        buf[0] = 0;
    }
}

void PC98_GetVFKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i,const struct pc98_func_key_shortcut_def *keylist) {
    if (i >= 1 && i <= 5) {
        const pc98_func_key_shortcut_def &def = keylist[i-1];
        unsigned int j=0,o=0;

        /* if the shortcut starts with 0xFE then the next 5 chars are intended for display only
         * and the shortcut starts after that. Else the entire string is stuffed into the CON
         * device. */
        if (def.shortcut[0] == 0xFE)
            j = 6;

        while (j < MIN(0x0Eu,(unsigned int)def.length))
            buf[o++] = def.shortcut[j++];

        len = (size_t)o;
        buf[o] = 0;
    }
    else {
        len = 0;
        buf[0] = 0;
    }
}

void PC98_GetFuncKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i) {
    PC98_GetFuncKeyEscape(len,buf,i,pc98_func_key);
}

void PC98_GetShiftFuncKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i) {
    PC98_GetFuncKeyEscape(len,buf,i,pc98_func_key_shortcut);
}

void PC98_GetCtrlFuncKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i) {
    PC98_GetFuncKeyEscape(len,buf,i,pc98_func_key_ctrl);
}

void PC98_GetVFuncKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i) {
    PC98_GetVFKeyEscape(len,buf,i,pc98_vfunc_key);
}

void PC98_GetShiftVFuncKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i) {
    PC98_GetVFKeyEscape(len,buf,i,pc98_vfunc_key_shortcut);
}

void PC98_GetCtrlVFuncKeyEscape(size_t &len,unsigned char buf[16],const unsigned int i) {
    PC98_GetVFKeyEscape(len,buf,i,pc98_vfunc_key_ctrl);
}

void PC98_InitDefFuncRow(void) {
    for (unsigned int i=0;i < 10;i++) {
        pc98_func_key_shortcut_def &def = pc98_func_key[i];

        def.pad = 0x00;
        def.set_text_and_escape(pc98_func_key_default[i],pc98_func_key_escapes_default[i]);
    }
    for (unsigned int i=0;i < 10;i++) {
        pc98_func_key_shortcut_def &def = pc98_func_key_shortcut[i];

        def.pad = 0x00;
        def.set_shortcut(pc98_shcut_key_defaults[i]);
    }
    for (unsigned int i=0;i < 11;i++) {
        pc98_func_key_shortcut_def &def = pc98_editor_key_escapes[i];

        def.pad = 0x00;
        def.set_shortcut(pc98_editor_key_escapes_default[i]);
    }
    for (unsigned int i=0;i < 10;i++) {
        pc98_func_key_shortcut_def &def = pc98_func_key_ctrl[i];

        def.pad = 0x00;
        def.set_shortcut("");
    }
    /* MS-DOS by default does not assign the VFn keys anything */
    for (unsigned int i=0;i < 5;i++) {
        pc98_func_key_shortcut_def &def = pc98_vfunc_key[i];

        def.pad = 0x00;
        def.set_shortcut("");
    }
    for (unsigned int i=0;i < 5;i++) {
        pc98_func_key_shortcut_def &def = pc98_vfunc_key_shortcut[i];

        def.pad = 0x00;
        def.set_shortcut("");
    }
    for (unsigned int i=0;i < 5;i++) {
        pc98_func_key_shortcut_def &def = pc98_vfunc_key_ctrl[i];

        def.pad = 0x00;
        def.set_shortcut("");
    }
}

#include "int10.h"

void draw_pc98_function_row_elem(unsigned int o, unsigned int co, const struct pc98_func_key_shortcut_def& key) {
    const unsigned char *str = key.shortcut;
    unsigned int j = 0,i = 0;

    // NTS: Some shortcut strings start with 0xFE, which is rendered as an invisible space anyway.

    // NTS: Apparently the strings are Shift-JIS and expected to render to the function key row
    //      the same way the console normally does it.
    ShiftJISDecoder sjis;

    while (j < 6u && str[i] != 0) {
        if (sjis.take(str[i++])) {
            if (sjis.doublewide) {
                /* JIS conversion to WORD value appropriate for text RAM */
                if (sjis.b2 != 0) sjis.b1 -= 0x20;

                uint16_t w = (sjis.b2 << 8) + sjis.b1;
                mem_writew(0xA0000+((o+co+j)*2u),w);
                mem_writeb(0xA2000+((o+co+j)*2u),0xE5); // white  reverse  visible
                j++;
                mem_writew(0xA0000+((o+co+j)*2u),w);
                mem_writeb(0xA2000+((o+co+j)*2u),0xE5); // white  reverse  visible
                j++;
            }
            else {
                mem_writew(0xA0000+((o+co+j)*2u),str[j]);
                mem_writeb(0xA2000+((o+co+j)*2u),0xE5); // white  reverse  visible
                j++;
            }
        }
    }

    while (j < 6u) {
        mem_writew(0xA0000+((o+co+j)*2u),(unsigned char)(' '));
        mem_writeb(0xA2000+((o+co+j)*2u),0xE5); // white  reverse  visible
        j++;
    }
}

void draw_pc98_function_row(unsigned int o, const struct pc98_func_key_shortcut_def* keylist) {
    for (unsigned int i=0u;i < 5u;i++)
        draw_pc98_function_row_elem(o,4u + (i * 7u),keylist[i]);
    for (unsigned int i=5u;i < 10u;i++)
        draw_pc98_function_row_elem(o,42u + ((i - 5u) * 7u),keylist[i]);
}

unsigned int pc98_DOS_console_rows(void) {
    Bit8u b = real_readb(0x60,0x113);

    return (b & 0x01) ? 25 : 20;
}

void update_pc98_function_row(unsigned char setting,bool force_redraw) {
    if (!force_redraw && pc98_function_row_mode == setting) return;
    pc98_function_row_mode = setting;

    unsigned int total_rows = pc98_DOS_console_rows();
    unsigned char c = real_readb(0x60,0x11C);
    unsigned char r = real_readb(0x60,0x110);
    unsigned int o = 80 * (total_rows - 1);

    if (pc98_function_row_mode != 0) {
        if (r > (total_rows - 2)) {
            r = (total_rows - 2);
            void INTDC_CL10h_AH04h(void);
            INTDC_CL10h_AH04h();
        }
    }

    real_writeb(0x60,0x112,total_rows - 1 - ((pc98_function_row_mode != 0) ? 1 : 0));

    if (pc98_function_row_mode == 2) {
        /* draw the function row.
         * based on on real hardware:
         *
         * The function key is 72 chars wide. 4 blank chars on each side of the screen.
         * It is divided into two halves, 36 chars each.
         * Within each half, aligned to it's side, is 5 x 7 regions.
         * 6 of the 7 are inverted. centered in the white block is the function key. */
        for (unsigned int i=0;i < 40;) {
            mem_writew(0xA0000+((o+i)*2),0x0000);
            mem_writeb(0xA2000+((o+i)*2),0xE1);

            mem_writew(0xA0000+((o+(79-i))*2),0x0000);
            mem_writeb(0xA2000+((o+(79-i))*2),0xE1);

            if (i >= 3 && i < 38)
                i += 7;
            else
                i++;
        }

        mem_writew(0xA0000+((o+2)*2),(unsigned char)('*'));
        mem_writeb(0xA2000+((o+2)*2),0xE1);

        draw_pc98_function_row(o,pc98_func_key_shortcut);
    }
    else if (pc98_function_row_mode == 1) {
        /* draw the function row.
         * based on on real hardware:
         *
         * The function key is 72 chars wide. 4 blank chars on each side of the screen.
         * It is divided into two halves, 36 chars each.
         * Within each half, aligned to it's side, is 5 x 7 regions.
         * 6 of the 7 are inverted. centered in the white block is the function key. */
        for (unsigned int i=0;i < 40;) {
            mem_writew(0xA0000+((o+i)*2),0x0000);
            mem_writeb(0xA2000+((o+i)*2),0xE1);

            mem_writew(0xA0000+((o+(79-i))*2),0x0000);
            mem_writeb(0xA2000+((o+(79-i))*2),0xE1);

            if (i >= 3 && i < 38)
                i += 7;
            else
                i++;
        }

        draw_pc98_function_row(o,pc98_func_key);
    }
    else {
        /* erase the function row */
        for (unsigned int i=0;i < 80;i++) {
            mem_writew(0xA0000+((o+i)*2),0x0000);
            mem_writeb(0xA2000+((o+i)*2),0xE1);
        }
    }

    real_writeb(0x60,0x11C,c);
    real_writeb(0x60,0x110,r);

    real_writeb(0x60,0x111,(pc98_function_row_mode != 0) ? 0x01 : 0x00);/* function key row display status */

    void vga_pc98_direct_cursor_pos(Bit16u address);
    vga_pc98_direct_cursor_pos((r*80)+c);
}

void pc98_function_row_user_toggle(void) {
    if (pc98_function_row_mode >= 2)
        update_pc98_function_row(0,true);
    else
        update_pc98_function_row(pc98_function_row_mode+1,true);
}

void pc98_set_digpal_entry(unsigned char ent,unsigned char grb);
void PC98_show_cursor(bool show);

extern bool                         gdc_5mhz_mode;
extern bool                         enable_pc98_egc;
extern bool                         enable_pc98_grcg;
extern bool                         enable_pc98_16color;
extern bool                         enable_pc98_256color;
extern bool                         enable_pc98_188usermod;
extern bool                         pc98_31khz_mode;
extern bool                         pc98_attr4_graphic;

extern unsigned char                pc98_text_first_row_scanline_start;  /* port 70h */
extern unsigned char                pc98_text_first_row_scanline_end;    /* port 72h */
extern unsigned char                pc98_text_row_scanline_blank_at;     /* port 74h */
extern unsigned char                pc98_text_row_scroll_lines;          /* port 76h */
extern unsigned char                pc98_text_row_scroll_count_start;    /* port 78h */
extern unsigned char                pc98_text_row_scroll_num_lines;      /* port 7Ah */

void pc98_update_text_layer_lineheight_from_bda(void) {
//    unsigned char c = mem_readb(0x53C);
    unsigned char lineheight = mem_readb(0x53B) + 1;

    pc98_gdc[GDC_MASTER].force_fifo_complete();
    pc98_gdc[GDC_MASTER].row_height = lineheight;

    if (lineheight > 20) { // usually 24
        pc98_text_first_row_scanline_start = 0x1C;
        pc98_text_first_row_scanline_end = lineheight - 5;
        pc98_text_row_scanline_blank_at = 16;
    }
    else if (lineheight > 16) { // usually 20
        pc98_text_first_row_scanline_start = 0x1E;
        pc98_text_first_row_scanline_end = lineheight - 3;
        pc98_text_row_scanline_blank_at = 16;
    }
    else {
        pc98_text_first_row_scanline_start = 0;
        pc98_text_first_row_scanline_end = lineheight - 1;
        pc98_text_row_scanline_blank_at = lineheight;
    }

    pc98_text_row_scroll_lines = 0;
    pc98_text_row_scroll_count_start = 0;
    pc98_text_row_scroll_num_lines = 0;

    vga.crtc.cursor_start = 0;
    vga.draw.cursor.sline = 0;

    vga.crtc.cursor_end   = lineheight - 1;
    vga.draw.cursor.eline = lineheight - 1;
}

void pc98_update_text_lineheight_from_bda(void) {
    unsigned char b597 = mem_readb(0x597);
    unsigned char c = mem_readb(0x53C);
    unsigned char lineheight;

    if ((b597 & 0x3) == 0x3) {//WARNING: This could be wrong
        if (c & 0x10)/*30-line mode (30x16 = 640x480)*/
            lineheight = 16;
        else if (c & 0x01)/*20-line mode (20x24 = 640x480)*/
            lineheight = 24;
        else/*25-line mode (25x19 = 640x480)*/
            lineheight = 19;
    }
    else {
        if (c & 0x10)/*30-line mode (30x13 = 640x400)*/
            lineheight = 13;//??
        else if (c & 0x01)/*20-line mode (20x20 = 640x400)*/
            lineheight = 20;
        else/*25-line mode (25x16 = 640x400)*/
            lineheight = 16;
    }

    mem_writeb(0x53B,lineheight - 1);
}

/* TODO: The text and graphics code that talks to the GDC will need to be converted
 *       to CPU I/O read and write calls. I think the reason Windows 3.1's 16-color
 *       driver is causing screen distortion when going fullscreen with COMMAND.COM,
 *       and the reason COMMAND.COM windowed doesn't show anything, has to do with
 *       the fact that Windows 3.1 expects this BIOS call to use I/O so it can trap
 *       and virtualize the GDC and display state.
 *
 *       Obviously for the same reason VGA INT 10h emulation in IBM PC mode needs to
 *       do the same to prevent display and virtualization problems with the IBM PC
 *       version of Windows 3.1.
 *
 *       See also: [https://github.com/joncampbell123/dosbox-x/issues/1066] */
static Bitu INT18_PC98_Handler(void) {
    Bit16u temp16;

#if 0
    if (reg_ah >= 0x0A) {
            LOG_MSG("PC-98 INT 18h unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                reg_ax,
                reg_bx,
                reg_cx,
                reg_dx,
                reg_si,
                reg_di,
                SegValue(ds),
                SegValue(es));
    }
#endif
 
    /* NTS: Based on information gleaned from Neko Project II source code including comments which
     *      I've run through GNU iconv to convert from SHIFT-JIS to UTF-8 here in case Google Translate
     *      got anything wrong. */
    switch (reg_ah) {
        case 0x00: /* Reading of key data (キー・データの読みだし) */
            /* FIXME: We use the IBM PC/AT keyboard buffer to fake this call.
             *        This will be replaced with PROPER emulation once the PC-98 keyboard handler has been
             *        updated to write the buffer the way PC-98 BIOSes do it.
             *
             *        IBM PC/AT keyboard buffer at 40:1E-40:3D
             *
             *        PC-98 keyboard buffer at 50:02-50:21 */
            /* This call blocks until keyboard input */
            if (INT16_get_key(temp16)) {
                reg_ax = temp16;
            }
            else {
                /* Keyboard checks.
                 * If the interrupt got masked, unmask it.
                 * If the keyboard has data waiting, make sure the interrupt signal is active in case the last interrupt handler
                 * handled the keyboard interrupt and never read the keyboard (Quarth).
                 *
                 * TODO: Is this what real PC-98 BIOSes do? */
                void check_keyboard_fire_IRQ1(void);
                check_keyboard_fire_IRQ1();
                IO_WriteB(0x02,IO_ReadB(0x02) & (~(1u << /*IRQ*/1u))); // unmask IRQ1

                reg_ip += 1; /* step over IRET, to NOPs which then JMP back to callback */
            }
            break;
        case 0x01: /* Sense of key buffer state (キー・バッファ状態のセンス) */
            /* This call returns whether or not there is input waiting.
             * The waiting data is read, but NOT discarded from the buffer. */
            if (INT16_peek_key(temp16)) {
                reg_ax = temp16;
                reg_bh = 1;
            }
            else {
                /* Keyboard checks.
                 * If the interrupt got masked, unmask it.
                 * If the keyboard has data waiting, make sure the interrupt signal is active in case the last interrupt handler
                 * handled the keyboard interrupt and never read the keyboard (Quarth).
                 *
                 * TODO: Is this what real PC-98 BIOSes do? */
                void check_keyboard_fire_IRQ1(void);
                check_keyboard_fire_IRQ1();
                IO_WriteB(0x02,IO_ReadB(0x02) & (~(1u << /*IRQ*/1u))); // unmask IRQ1

                reg_bh = 0;
            }
            break;
        case 0x02: /* Sense of shift key state (シフト・キー状態のセンス) */
            reg_al = mem_readb(0x53A);
            break;
        case 0x03: /* Initialization of keyboard interface (キーボード・インタフェイスの初期化) */
            /* TODO */
            break;
        case 0x04: /* Sense of key input state (キー入力状態のセンス) */
            reg_ah = mem_readb(0x52A + (unsigned int)(reg_al & 0x0Fu));
            /* Hack for "Shangrlia" by Elf: The game's regulation of animation speed seems to depend on
             * INT 18h AH=0x04 taking some amount of time. If we do not do this, animation will run way
             * too fast and everyone will be talking/moving at a million miles a second.
             *
             * This is based on comparing animation speed vs the same game on real Pentium-class PC-98
             * hardware.
             *
             * Looking at the software loop involved during opening cutscenes, the game is constantly
             * polling INT 18h AH=04h (keyboard state) and INT 33h AH=03h (mouse button/position state)
             * while animating the characters on the screen. Without this delay, animation runs way too
             * fast.
             *
             * This guess is also loosely based on a report by the Touhou Community Reliant Automatic Patcher
             * that Touhou Project directly reads this byte but delays by 0.6ms to handle the fact that
             * the bit in question may toggle while the key is held down due to the scan codes returned by
             * the keyboard.
             *
             * This is a guess, but it seems to help animation speed match that of real hardware regardless
             * of cycle count in DOSBox-X. */
            CPU_Cycles -= (cpu_cycles_count_t)(CPU_CycleMax * 0.006);
            break;
        case 0x05: /* Key input sense (キー入力センス) */
            /* This appears to return a key from the buffer (and remove from
             * buffer) or return BH == 0 to signal no key was pending. */
            if (INT16_get_key(temp16)) {
                reg_ax = temp16;
                reg_bh = 1;
            }
            else {
                /* Keyboard checks.
                 * If the interrupt got masked, unmask it.
                 * If the keyboard has data waiting, make sure the interrupt signal is active in case the last interrupt handler
                 * handled the keyboard interrupt and never read the keyboard (Quarth).
                 *
                 * TODO: Is this what real PC-98 BIOSes do? */
                void check_keyboard_fire_IRQ1(void);
                check_keyboard_fire_IRQ1();
                IO_WriteB(0x02,IO_ReadB(0x02) & (~(1u << /*IRQ*/1u))); // unmask IRQ1

                reg_bh = 0;
            }
            break;
        case 0x0A: /* set CRT mode */
            /* bit      off         on
                0       25lines     20lines
                1       80cols      40cols
                2       v.lines     simp.graphics
                3       K-CG access mode(not used in PC-98) */
            
            //TODO: set 25/20 lines mode and 80/40 columns mode.
            //Attribute bit (bit 2)
            pc98_attr4_graphic = !!(reg_al & 0x04);
            pc98_40col_text = !!(reg_al & 0x02);

            mem_writeb(0x53C,(mem_readb(0x53C) & 0xF0u) | (reg_al & 0x0Fu));

            if (reg_al & 8)
                LOG_MSG("INT 18H AH=0Ah warning: K-CG dot access mode not supported");

            pc98_update_text_lineheight_from_bda();
            pc98_update_text_layer_lineheight_from_bda();

            /* Apparently, this BIOS call also hides the cursor */
            PC98_show_cursor(0);
            break;
        case 0x0B: /* get CRT mode */
            /* bit      off         on
                0       25lines     20lines
                1       80cols      40cols
                2       v.lines     simp.graphics
                3       K-CG access mode(not used in PC-98) 
                7       std CRT     hi-res CRT */
            /* NTS: I assume that real hardware doesn't offer a way to read back the state of these bits,
             *      so the BIOS's only option is to read the mode byte back from the data area.
             *      Neko Project II agrees. */
            reg_al = mem_readb(0x53C);
            break;
        // TODO: "Edge" is using INT 18h AH=06h, what is that?
        //       (Something to do with the buffer [https://ia801305.us.archive.org/8/items/PC9800TechnicalDataBookBIOS1992/PC-9800TechnicalDataBook_BIOS_1992_text.pdf])
        //       Neko Project is also unaware of such a call.
        case 0x0C: /* text layer enable */
            pc98_gdc[GDC_MASTER].force_fifo_complete();
            pc98_gdc[GDC_MASTER].display_enable = true;
            break;
        case 0x0D: /* text layer disable */
            pc98_gdc[GDC_MASTER].force_fifo_complete();
            pc98_gdc[GDC_MASTER].display_enable = false;
            break;
        case 0x0E: /* set text display area (DX=byte offset) */
            pc98_gdc[GDC_MASTER].force_fifo_complete();
            pc98_gdc[GDC_MASTER].param_ram[0] = (reg_dx >> 1) & 0xFF;
            pc98_gdc[GDC_MASTER].param_ram[1] = (reg_dx >> 9) & 0xFF;
            pc98_gdc[GDC_MASTER].param_ram[2] = (400 << 4) & 0xFF;
            pc98_gdc[GDC_MASTER].param_ram[3] = (400 << 4) >> 8;
            break;
        case 0x11: /* show cursor */
            PC98_show_cursor(true);
            break;
        case 0x12: /* hide cursor */
            PC98_show_cursor(false);
            break;
        case 0x13: /* set cursor position (DX=byte position) */
            void vga_pc98_direct_cursor_pos(Bit16u address);

            pc98_gdc[GDC_MASTER].force_fifo_complete();
            vga_pc98_direct_cursor_pos(reg_dx >> 1);
            break;
        case 0x14: /* read FONT RAM */
            {
                unsigned int i,o,r;

                /* DX = code (must be 0x76xx or 0x7700)
                 * BX:CX = 34-byte region to write to */
                if (reg_dh == 0x80u) { /* 8x16 ascii */
                    i = ((unsigned int)reg_bx << 4u) + reg_cx + 2u;
                    mem_writew(i-2u,0x0102u);
                    for (r=0;r < 16u;r++) {
                        o = (reg_dl*16u)+r;

                        assert((o+2u) <= sizeof(vga.draw.font));

                        mem_writeb(i+r,vga.draw.font[o]);
                    }
                }
                else if ((reg_dh & 0xFC) == 0x28) { /* 8x16 kanji */
                    i = ((unsigned int)reg_bx << 4u) + reg_cx + 2u;
                    mem_writew(i-2u,0x0102u);
                    for (r=0;r < 16u;r++) {
                        o = (((((reg_dl & 0x7Fu)*128u)+((reg_dh - 0x20u) & 0x7Fu))*16u)+r)*2u;

                        assert((o+2u) <= sizeof(vga.draw.font));

                        mem_writeb(i+r+0u,vga.draw.font[o+0u]);
                    }
                }
                else if (reg_dh != 0) { /* 16x16 kanji */
                    i = ((unsigned int)reg_bx << 4u) + reg_cx + 2u;
                    mem_writew(i-2u,0x0202u);
                    for (r=0;r < 16u;r++) {
                        o = (((((reg_dl & 0x7Fu)*128u)+((reg_dh - 0x20u) & 0x7Fu))*16u)+r)*2u;

                        assert((o+2u) <= sizeof(vga.draw.font));

                        mem_writeb(i+(r*2u)+0u,vga.draw.font[o+0u]);
                        mem_writeb(i+(r*2u)+1u,vga.draw.font[o+1u]);
                    }
                }
                else {
                    LOG_MSG("PC-98 INT 18h AH=14h font RAM read ignored, code 0x%04x not supported",reg_dx);
                }
            }
            break;
        case 0x16: /* fill screen with chr + attr */
            {
                /* DL = character
                 * DH = attribute */
                unsigned int i;

                for (i=0;i < 0x2000;i += 2) {
                    vga.mem.linear[i+0] = reg_dl;
                    vga.mem.linear[i+1] = 0x00;
                }
                for (   ;i < 0x3FE0;i += 2) {
                    vga.mem.linear[i+0] = reg_dh;
                    vga.mem.linear[i+1] = 0x00;
                }
            }
            break;
        case 0x17: /* BELL ON */
            IO_WriteB(0x37,0x06);
            break;
        case 0x18: /* BELL OFF */
            IO_WriteB(0x37,0x07);
            break;
        case 0x1A: /* load FONT RAM */
            {
                /* DX = code (must be 0x76xx or 0x7700)
                 * BX:CX = 34-byte region to read from */
                if ((reg_dh & 0x7Eu) == 0x76u) {
                    unsigned int i = ((unsigned int)reg_bx << 4u) + reg_cx + 2u;
                    for (unsigned int r=0;r < 16u;r++) {
                        unsigned int o = (((((reg_dl & 0x7Fu)*128u)+((reg_dh - 0x20u) & 0x7Fu))*16u)+r)*2u;

                        assert((o+2u) <= sizeof(vga.draw.font));

                        vga.draw.font[o+0u] = mem_readb(i+(r*2u)+0u);
                        vga.draw.font[o+1u] = mem_readb(i+(r*2u)+1u);
                    }
                }
                else {
                    LOG_MSG("PC-98 INT 18h AH=1Ah font RAM load ignored, code 0x%04x out of range",reg_dx);
                }
            }
            break;
        case 0x30: /* Set display mode */
            /* FIXME: There is still a lot that is inaccurate about this call */
            if (enable_pc98_egc) {
                unsigned char b597 = mem_readb(0x597);
                unsigned char tstat = mem_readb(0x53C);
                unsigned char b54C = mem_readb(0x54C);
                unsigned char ret = 0x05; // according to NP2

                // assume the same as AH=42h
                while (!(IO_ReadB(0x60) & 0x20/*vertical retrace*/)) {
                    void CALLBACK_Idle(void);
                    CALLBACK_Idle();
                }

                LOG_MSG("PC-98 INT 18 AH=30h AL=%02Xh BH=%02Xh",reg_al,reg_bh);

                if ((reg_bh & 0x30) == 0x30) { // 640x480
                    if ((reg_al & 0xC) == 0x0C) { // 31KHz sync
                        void PC98_Set31KHz_480line(void);
                        pc98_31khz_mode = true;
                        PC98_Set31KHz_480line();

                        void pc98_port6A_command_write(unsigned char b);
                        pc98_port6A_command_write(0x69); // disable 128KB wrap

                        b54C = (b54C & (~0x20)) + ((reg_al & 0x04) ? 0x20 : 0x00);

                        pc98_gdc[GDC_MASTER].force_fifo_complete();
                        pc98_gdc[GDC_SLAVE].force_fifo_complete();

                        // according to real hardware, this also hides the text layer for some reason
                        pc98_gdc[GDC_MASTER].display_enable = false;

                        /* clear PRAM, graphics */
                        for (unsigned int i=0;i < 16;i++)
                            pc98_gdc[GDC_SLAVE].param_ram[i] = 0x00;

                        /* reset scroll area of graphics */
                        pc98_gdc[GDC_SLAVE].param_ram[0] = 0;
                        pc98_gdc[GDC_SLAVE].param_ram[1] = 0;

                        pc98_gdc[GDC_SLAVE].param_ram[2] = 0xF0;
                        pc98_gdc[GDC_SLAVE].param_ram[3] = 0x3F + (gdc_5mhz_according_to_bios()?0x40:0x00/*IM bit*/);
                        pc98_gdc[GDC_SLAVE].display_pitch = gdc_5mhz_according_to_bios() ? 80u : 40u;

                        pc98_gdc[GDC_SLAVE].doublescan = false;
                        pc98_gdc[GDC_SLAVE].row_height = 1;

                        b597 = (b597 & ~3u) + ((Bit8u)(reg_bh >> 4u) & 3u);

                        pc98_gdc_vramop &= ~(1 << VOPBIT_ACCESS);
                        pc98_update_cpu_page_ptr();

                        GDC_display_plane = GDC_display_plane_pending = 0;
                        pc98_update_display_page_ptr();

                        /* based on real hardware behavior, this ALSO sets 256-color mode */
                        void pc98_port6A_command_write(unsigned char b);
                        pc98_port6A_command_write(0x07);        // enable EGC
                        pc98_port6A_command_write(0x01);        // enable 16-color
                        pc98_port6A_command_write(0x21);        // enable 256-color
                    }
                    else {
                        // according to Neko Project II, this case is ignored.
                        // this is confirmed on real hardware as well.
                        LOG_MSG("PC-98 INT 18h AH=30h attempt to set 640x480 mode with 24KHz hsync which is not supported by the platform");
                        ret = 0;
                    }
                }
                else { // 640x400 or 640x200
                    // TODO: A PC9821Lt2 laptop's BIOS refuses to allow 31khz except for 640x480 mode.
                    //       Perhaps it's just a technical restriction of the LCD display.
                    //
                    //       Check on other PC-98 hardware to see what the policy is for 31khz in all modes.
                    //       That restriction would make no sense on another system I have that has a VGA
                    //       port and a default setting of 70Hz / 31KHz 640x400.
                    if ((reg_al & 0x0C) < 0x08) { /* bits [3:2] == 0x */
                        LOG_MSG("PC-98 INT 18h AH=30h attempt to set 15KHz hsync which is not yet supported");
                        ret = 0;
                    }
                    else {
                        if ((reg_al ^ (((b54C & 0x20) ? 3 : 2) << 2)) & 0x0C) { /* change in bits [3:2] */
                            LOG_MSG("PC-98 change in hsync frequency to %uHz",(reg_al & 0x04) ? 31 : 24);

                            if (reg_al & 4) {
                                void PC98_Set31KHz(void);
                                pc98_31khz_mode = true;
                                PC98_Set31KHz();
                            }
                            else {
                                void PC98_Set24KHz(void);
                                pc98_31khz_mode = false;
                                PC98_Set24KHz();
                            }

                            b54C = (b54C & (~0x20)) + ((reg_al & 0x04) ? 0x20 : 0x00);
                        }
                    }

                    void pc98_port6A_command_write(unsigned char b);
                    pc98_port6A_command_write(0x68); // restore 128KB wrap

                    pc98_gdc[GDC_MASTER].force_fifo_complete();
                    pc98_gdc[GDC_SLAVE].force_fifo_complete();

                    // 640x480 forces 256-color mode.
                    // the 400 line modes (this case) do not clear 256-color mode.

                    // according to real hardware, this also hides the text layer for some reason
                    pc98_gdc[GDC_MASTER].display_enable = false;

                    /* clear PRAM, graphics */
                    for (unsigned int i=0;i < 16;i++)
                        pc98_gdc[GDC_SLAVE].param_ram[i] = 0x00;

                    /* reset scroll area of graphics */
                    if ((reg_bh & 0x30) == 0x10) { /* 640x200 upper half    bits [5:4] == 1 */
                        pc98_gdc[GDC_SLAVE].param_ram[0] = (200*40) & 0xFF;
                        pc98_gdc[GDC_SLAVE].param_ram[1] = (200*40) >> 8;
                    }
                    else {
                        pc98_gdc[GDC_SLAVE].param_ram[0] = 0;
                        pc98_gdc[GDC_SLAVE].param_ram[1] = 0;
                    }

                    pc98_gdc[GDC_SLAVE].param_ram[2] = 0xF0;
                    pc98_gdc[GDC_SLAVE].param_ram[3] = 0x3F + (gdc_5mhz_according_to_bios()?0x40:0x00/*IM bit*/);
                    pc98_gdc[GDC_SLAVE].display_pitch = gdc_5mhz_according_to_bios() ? 80u : 40u;

                    if ((reg_bh & 0x20) == 0x00) { /* 640x200 */
                        pc98_gdc[GDC_SLAVE].doublescan = true;
                        pc98_gdc[GDC_SLAVE].row_height = pc98_gdc[GDC_SLAVE].doublescan ? 2 : 1;
                    }
                    else {
                        pc98_gdc[GDC_SLAVE].doublescan = false;
                        pc98_gdc[GDC_SLAVE].row_height = 1;
                    }

                    b597 = (b597 & ~3u) + ((Bit8u)(reg_bh >> 4u) & 3u);

                    pc98_gdc_vramop &= ~(1 << VOPBIT_ACCESS);
                    pc98_update_cpu_page_ptr();

                    GDC_display_plane = GDC_display_plane_pending = 0;
                    pc98_update_display_page_ptr();
                }

                tstat &= ~(0x10 | 0x01);
                if (reg_bh & 2)
                    tstat |= 0x10;
                else if ((reg_bh & 1) == 0)
                    tstat |= 0x01;

                mem_writeb(0x597,b597);
                mem_writeb(0x53C,tstat);
                mem_writeb(0x54C,b54C);

                pc98_update_text_lineheight_from_bda();
                pc98_update_text_layer_lineheight_from_bda();

                // according to real hardware (PC-9821Lt2), AH=5 on success (same as NP2)
                // or AH is unchanged on failure and AL=1 and BH=1 (NOT the same as NP2)
                if (ret == 0x05) reg_ah = ret;
                reg_al = (ret == 0x05) ? 0x00 : 0x01; // according to NP2
                reg_bh = (ret == 0x05) ? 0x00 : 0x01; // according to NP2
            }
            break;
        case 0x31: /* Return display mode and status */
            /* NTS: According to NP II this call shouldn't even work unless you first call AH=30h to set 640x480 mode.
             *      It seems that is wrong. Real hardware will still return the current mode regardless. */
            if (enable_pc98_egc) { /* FIXME: INT 18h AH=31/30h availability is tied to EGC enable */
                unsigned char b597 = mem_readb(0x597);
                unsigned char tstat = mem_readb(0x53C);
                unsigned char b54C = mem_readb(0x54C);

                /* 54Ch:
                 * bit[5:5] = Horizontal sync rate                      1=31.47KHz      0=24.83KHz */

                /* Return values:
                 *
                 * AL =
                 *      bit [7:7] = ?
                 *      bit [6:6] = ?
                 *      bit [5:5] = ?
                 *      bit [4:4] = ?
                 *      bit [3:2] = horizontal sync
                 *                   00 = 15.98KHz
                 *                   01 = ?
                 *                   10 = 24.83KHz
                 *                   11 = 31.47KHz
                 *      bit [1:1] = ?
                 *      bit [0:0] = interlaced (1=yes 0=no)
                 * BH =
                 *      bit [7:7] = ?
                 *      bit [6:6] = ?
                 *      bit [5:4] = graphics video mode
                 *                   00 = 640x200 (upper half)
                 *                   01 = 640x200 (lower half)
                 *                   10 = 640x400
                 *                   11 = 640x480
                 *      bit [3:3] = ?
                 *      bit [2:2] = ?
                 *      bit [1:0] = number of text rows
                 *                   00 = 20 rows
                 *                   01 = 25 rows
                 *                   10 = 30 rows
                 *                   11 = ?
                 */
                reg_al =
                    (((b54C & 0x20) ? 3 : 2) << 2)/*hsync*/;
                reg_bh =
                    ((b597 & 3) << 4)/*graphics video mode*/;
                if (tstat & 0x10)
                    reg_bh |= 2;/*30 rows*/
                else if ((tstat & 0x01) == 0)
                    reg_bh |= 1;/*25 rows*/
            }
            break;
        /* From this point on the INT 18h call list appears to wander off from the keyboard into CRT/GDC/display management. */
        case 0x40: /* Start displaying the graphics screen (グラフィック画面の表示開始) */
            pc98_gdc[GDC_SLAVE].force_fifo_complete();
            pc98_gdc[GDC_SLAVE].display_enable = true;
 
            {
                unsigned char b = mem_readb(0x54C/*MEMB_PRXCRT*/);
                mem_writeb(0x54C/*MEMB_PRXCRT*/,b | 0x80);
            }
            break;
        case 0x41: /* Stop displaying the graphics screen (グラフィック画面の表示終了) */
            pc98_gdc[GDC_SLAVE].force_fifo_complete();
            pc98_gdc[GDC_SLAVE].display_enable = false;

            {
                unsigned char b = mem_readb(0x54C/*MEMB_PRXCRT*/);
                mem_writeb(0x54C/*MEMB_PRXCRT*/,b & (~0x80));
            }
            break;
        case 0x42: /* Display area setup (表示領域の設定) */
            // HACK for Quarth: If the game has triggered vsync interrupt, wait for it.
            // Quarth's vsync interrupt will reprogram the display partitions back to what
            // it would have set for gameplay after this modeset and cause display problems
            // with the main menu. Waiting one vertical retrace period before mode setting
            // gives Quarth one last frame to reprogram partitions before realizing that
            // it's time to stop it.
            //
            // If the BIOS on real hardware has any check like this, it's probably a loop
            // to wait for vsync.
            //
            // The interrupt does NOT cancel the vertical retrace interrupt. Some games
            // (Rusty) will not work properly if this call cancels the vertical retrace
            // interrupt.
            while (!(IO_ReadB(0x60) & 0x20/*vertical retrace*/)) {
                void CALLBACK_Idle(void);
                CALLBACK_Idle();
            }

            pc98_gdc[GDC_MASTER].force_fifo_complete();
            pc98_gdc[GDC_SLAVE].force_fifo_complete();

            /* clear PRAM, graphics */
            for (unsigned int i=0;i < 16;i++)
                pc98_gdc[GDC_SLAVE].param_ram[i] = 0x00;

            /* reset scroll area of graphics */
            if ((reg_ch & 0xC0) == 0x40) { /* 640x200 G-RAM upper half */
                pc98_gdc[GDC_SLAVE].param_ram[0] = (200*40) & 0xFF;
                pc98_gdc[GDC_SLAVE].param_ram[1] = (200*40) >> 8;
            }
            else {
                pc98_gdc[GDC_SLAVE].param_ram[0] = 0;
                pc98_gdc[GDC_SLAVE].param_ram[1] = 0;
            }

            pc98_gdc[GDC_SLAVE].param_ram[2] = 0xF0;
            pc98_gdc[GDC_SLAVE].param_ram[3] = 0x3F + (gdc_5mhz_according_to_bios()?0x40:0x00/*IM bit*/);
            pc98_gdc[GDC_SLAVE].display_pitch = gdc_5mhz_according_to_bios() ? 80u : 40u;

            // CH
            //   [7:6] = G-RAM setup
            //           00 = no graphics (?)
            //           01 = 640x200 upper half
            //           10 = 640x200 lower half
            //           11 = 640x400
            //   [5:5] = CRT
            //           0 = color
            //           1 = monochrome
            //   [4:4] = Display bank

            // FIXME: This is a guess. I have no idea as to actual behavior, yet.
            //        This seems to help with clearing the text layer when games start the graphics.
            //        This is ALSO how we will detect games that switch on the 200-line double-scan mode vs 400-line mode.
            if ((reg_ch & 0xC0) != 0) {
                pc98_gdc[GDC_SLAVE].doublescan = ((reg_ch & 0xC0) == 0x40) || ((reg_ch & 0xC0) == 0x80);
                pc98_gdc[GDC_SLAVE].row_height = pc98_gdc[GDC_SLAVE].doublescan ? 2 : 1;

                /* update graphics mode bits */
                {
                    unsigned char b = mem_readb(0x597);

                    b &= ~3;
                    b |= ((reg_ch >> 6) - 1) & 3;

                    mem_writeb(0x597,b);
                }
            }
            else {
                pc98_gdc[GDC_SLAVE].doublescan = false;
                pc98_gdc[GDC_SLAVE].row_height = 1;
            }

            {
                unsigned char b = mem_readb(0x54C/*MEMB_PRXCRT*/);

                // Real hardware behavior: graphics selection updated by BIOS to reflect MEMB_PRXCRT state
                pc98_gdc[GDC_SLAVE].display_enable = !!(b & 0x80);
            }

            pc98_gdc_vramop &= ~(1 << VOPBIT_ACCESS);
            pc98_update_cpu_page_ptr();

            GDC_display_plane = GDC_display_plane_pending = (reg_ch & 0x10) ? 1 : 0;
            pc98_update_display_page_ptr();

            prev_pc98_mode42 = reg_ch;

            LOG_MSG("PC-98 INT 18 AH=42h CH=0x%02X",reg_ch);
            break;
        case 0x43:  // Palette register settings? Only works in digital mode? --leonier
                    //
                    // This is said to fix Thexder's GAME ARTS logo. --Jonathan C.
                    //
                    // TODO: Validate this against real PC-98 hardware and BIOS
            {
                unsigned int gbcpc = SegValue(ds)*0x10u + reg_bx;
                for(unsigned int i=0;i<4;i++)
                {
                    unsigned char p=mem_readb(gbcpc+4u+i);
                    pc98_set_digpal_entry(7u-2u*i, p&0xFu);
                    pc98_set_digpal_entry(6u-2u*i, p>>4u);
                }
                LOG_MSG("PC-98 INT 18 AH=43h CX=0x%04X DS=0x%04X", reg_cx, SegValue(ds));
                break;
            }
        case 0x4D:  // 256-color enable
            if (reg_ch == 1) {
                void pc98_port6A_command_write(unsigned char b);
                pc98_port6A_command_write(0x07);        // enable EGC
                pc98_port6A_command_write(0x01);        // enable 16-color
                pc98_port6A_command_write(0x21);        // enable 256-color
                PC98_show_cursor(false);                // apparently hides the cursor?
            }
            else if (reg_ch == 0) {
                void pc98_port6A_command_write(unsigned char b);
                pc98_port6A_command_write(0x20);        // disable 256-color
                PC98_show_cursor(false);                // apparently hides the cursor?
            }
            else {
                LOG_MSG("PC-98 INT 18h AH=4Dh unknown CH=%02xh",reg_ch);
            }
            break;
        default:
            LOG_MSG("PC-98 INT 18h unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                reg_ax,
                reg_bx,
                reg_cx,
                reg_dx,
                reg_si,
                reg_di,
                SegValue(ds),
                SegValue(es));
            break;
    }

    /* FIXME: What do actual BIOSes do when faced with an unknown INT 18h call? */
    return CBRET_NONE;
}

#define PC98_FLOPPY_HIGHDENSITY     0x01
#define PC98_FLOPPY_2HEAD           0x02
#define PC98_FLOPPY_RPM_3MODE       0x04
#define PC98_FLOPPY_RPM_IBMPC       0x08

unsigned char PC98_BIOS_FLOPPY_BUFFER[32768]; /* 128 << 8 */

static unsigned int PC98_FDC_SZ_TO_BYTES(unsigned int sz) {
    return 128U << sz;
}

int PC98_BIOS_SCSI_POS(imageDisk *floppy,Bit32u &sector) {
    if (reg_al & 0x80) {
        Bit32u img_heads=0,img_cyl=0,img_sect=0,img_ssz=0;

        floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);

        /* DL = sector
         * DH = head
         * CX = track */
        if (reg_dl >= img_sect ||
            reg_dh >= img_heads ||
            reg_cx >= img_cyl) {
            return (reg_ah=0x60);
        }

        sector  = reg_cx;
        sector *= img_heads;
        sector += reg_dh;
        sector *= img_sect;
        sector += reg_dl;

//        LOG_MSG("Sector CHS %u/%u/%u -> %u (geo %u/%u/%u)",reg_cx,reg_dh,reg_dl,sector,img_cyl,img_heads,img_sect);
    }
    else {
        /* Linear LBA addressing */
        sector = ((unsigned int)reg_dl << 16UL) + reg_cx;
        /* TODO: SASI caps at 0x1FFFFF according to NP2 */
    }

    return 0;
}

void PC98_BIOS_SCSI_CALL(void) {
    Bit32u img_heads=0,img_cyl=0,img_sect=0,img_ssz=0;
    Bit32u memaddr,size,ssize;
    imageDisk *floppy;
    unsigned int i;
    Bit32u sector;
    int idx;

#if 0
            LOG_MSG("PC-98 INT 1Bh SCSI BIOS call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                    reg_ax,
                    reg_bx,
                    reg_cx,
                    reg_dx,
                    reg_si,
                    reg_di,
                    SegValue(ds),
                    SegValue(es));
#endif

    idx = (reg_al & 0xF) + 2;
    if (idx < 0 || idx >= MAX_DISK_IMAGES) {
        CALLBACK_SCF(true);
        reg_ah = 0x00;
        /* TODO? Error code? */
        return;
    }

    floppy = imageDiskList[idx];
    if (floppy == NULL) {
        CALLBACK_SCF(true);
        reg_ah = 0x60;
        return;
    }

    /* FIXME: According to NPKai, command is reg_ah & 0x1F not reg_ah & 0x0F. Right? */

    /* what to do is in the lower 4 bits of AH */
    switch (reg_ah & 0x0F) {
        case 0x05: /* write */
            if (PC98_BIOS_SCSI_POS(floppy,/*&*/sector) == 0) {
                floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);
                assert(img_ssz != 0);

                size = reg_bx;
                if (size == 0) size = 0x10000U;
                memaddr = ((unsigned int)SegValue(es) << 4u) + reg_bp;

                reg_ah = 0;
                CALLBACK_SCF(false);

//                LOG_MSG("WRITE memaddr=0x%lx size=0x%x sector=0x%lx ES:BP=%04x:%04X",
//                    (unsigned long)memaddr,(unsigned int)size,(unsigned long)sector,SegValue(es),reg_bp);

                while (size != 0) {
                    ssize = size;
                    if (ssize > img_ssz) ssize = img_ssz;

//                    LOG_MSG(" ... memaddr=0x%lx ssize=0x%x sector=0x%lx",
//                        (unsigned long)memaddr,(unsigned int)ssize,(unsigned long)sector);

                    for (i=0;i < ssize;i++) PC98_BIOS_FLOPPY_BUFFER[i] = mem_readb(memaddr+i);

                    if (floppy->Write_AbsoluteSector(sector,PC98_BIOS_FLOPPY_BUFFER) != 0) {
                        reg_ah = 0xD0;
                        CALLBACK_SCF(true);
                        break;
                    }

                    sector++;
                    size -= ssize;
                    memaddr += ssize;
                }
            }
            else {
                CALLBACK_SCF(true);
            }
            break;
        case 0x06: /* read */
            if (PC98_BIOS_SCSI_POS(floppy,/*&*/sector) == 0) {
                floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);
                assert(img_ssz != 0);

                size = reg_bx;
                if (size == 0) size = 0x10000U;
                memaddr = ((unsigned int)SegValue(es) << 4u) + reg_bp;

                reg_ah = 0;
                CALLBACK_SCF(false);

//                LOG_MSG("READ memaddr=0x%lx size=0x%x sector=0x%lx ES:BP=%04x:%04X",
//                    (unsigned long)memaddr,(unsigned int)size,(unsigned long)sector,SegValue(es),reg_bp);

                while (size != 0) {
                    ssize = size;
                    if (ssize > img_ssz) ssize = img_ssz;

//                    LOG_MSG(" ... memaddr=0x%lx ssize=0x%x sector=0x%lx",
//                        (unsigned long)memaddr,(unsigned int)ssize,(unsigned long)sector);

                    if (floppy->Read_AbsoluteSector(sector,PC98_BIOS_FLOPPY_BUFFER) == 0) {
                        for (i=0;i < ssize;i++) mem_writeb(memaddr+i,PC98_BIOS_FLOPPY_BUFFER[i]);
                    }
                    else {
                        reg_ah = 0xD0;
                        CALLBACK_SCF(true);
                        break;
                    }

                    sector++;
                    size -= ssize;
                    memaddr += ssize;
                }
            }
            else {
                CALLBACK_SCF(true);
            }
            break;
        case 0x03: /* according to NPKai source code: "negate ack" (cbus/scsicmd.c line 211, and 61) */
            reg_ah = 0x35;      /* according to scsicmd_negate() line 61, as translated by stat2ret[] by code line 228 */
            CALLBACK_SCF(false);
            // NTS: This is needed for an HDI image to boot that apparently contains FreeDOS98
            break;
        case 0x07: /* unknown, always succeeds */
            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x0E: /* unknown, always fails */
            reg_ah = 0x40;
            CALLBACK_SCF(true);
            break;
        case 0x04: /* drive status */
            if (reg_ah == 0x84) {
                floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);

                reg_dl = img_sect;
                reg_dh = img_heads; /* Max 16 */
                reg_cx = img_cyl;   /* Max 4096 */
                reg_bx = img_ssz;

                reg_ah = 0x00;
                CALLBACK_SCF(false);
                break;
            }
            else if (reg_ah == 0x04 || reg_ah == 0x14) {
                reg_ah = 0x00;
                CALLBACK_SCF(false);
            }
            else {
                goto default_goto;
            }
        default:
        default_goto:
            LOG_MSG("PC-98 INT 1Bh unknown SCSI BIOS call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                    reg_ax,
                    reg_bx,
                    reg_cx,
                    reg_dx,
                    reg_si,
                    reg_di,
                    SegValue(ds),
                    SegValue(es));
            CALLBACK_SCF(true);
            break;
    }
}

void PC98_BIOS_FDC_CALL_GEO_UNPACK(unsigned int &fdc_cyl,unsigned int &fdc_head,unsigned int &fdc_sect,unsigned int &fdc_sz) {
    fdc_cyl = reg_cl;
    fdc_head = reg_dh;
    fdc_sect = reg_dl;
    fdc_sz = reg_ch;
    if (fdc_sz > 8) fdc_sz = 8;
}

/* NTS: FDC calls reset IRQ 0 timer to a specific fixed interval,
 *      because the real BIOS likely does the same in the act of
 *      controlling the floppy drive.
 *
 *      Resetting the interval is required to prevent Ys II from
 *      crashing after disk swap (divide by zero/overflow) because
 *      Ys II reads the timer after INT 1Bh for whatever reason
 *      and the upper half of the timer byte later affects a divide
 *      by 3 in the code. */

void PC98_Interval_Timer_Continue(void);

bool enable_fdc_timer_hack = false;

void FDC_WAIT_TIMER_HACK(void) {
    unsigned int v;
    unsigned int c=0;

    // Explanation:
    //
    // Originally the FDC code here changed the timer interval back to the stock 100hz
    // normally used in PC-98, to fix Ys II. However that seems to break other booter
    // games that hook IRQ 0 directly and set the timer ONCE, then access the disk.
    //
    // For example, "Angelus" ran WAY too slow with the timer hack because it programs
    // the timer to a 600hz interval and expects it to stay that way.
    //
    // So the new method to satisfy both games is to loop here until the timer
    // count is below the maximum that would occur if the 100hz tick count were
    // still in effect, even if the timer interval was reprogrammed.
    //
    // NTS: Writing port 0x77 to relatch the timer also seems to break games
    //
    // TODO: As a safety against getting stuck, perhaps PIC_FullIndex() should be used
    //       to break out of the loop if this runs for more than 1 second, since that
    //       is a sign the timer is in an odd state that will never terminate this loop.

    v = ~0U;
    c = 10;
    do {
        void CALLBACK_Idle(void);
        CALLBACK_Idle();

        unsigned int pv = v;

        v  = (unsigned int)IO_ReadB(0x71);
        v |= (unsigned int)IO_ReadB(0x71) << 8u;

        if (v > pv) {
            /* if the timer rolled around, we might have missed the narrow window we're watching for */
            if (--c == 0) break;
        }
    } while (v >= 0x60);
}

void PC98_BIOS_FDC_CALL(unsigned int flags) {
    static unsigned int fdc_cyl[2]={0,0},fdc_head[2]={0,0},fdc_sect[2]={0,0},fdc_sz[2]={0,0}; // FIXME: Rename and move out. Making "static" is a hack here.
    Bit32u img_heads=0,img_cyl=0,img_sect=0,img_ssz=0;
    unsigned int drive;
    unsigned int status;
    unsigned int size,accsize,unitsize;
    unsigned long memaddr;
    imageDisk *floppy;

    /* AL bits[1:0] = which floppy drive */
    if ((reg_al & 3) >= 2) {
        /* This emulation only supports up to 2 floppy drives */
        CALLBACK_SCF(true);
        reg_ah = 0x00;
        /* TODO? Error code? */
        return;
    }

    floppy = GetINT13FloppyDrive(drive=(reg_al & 3));

    /* what to do is in the lower 4 bits of AH */
    switch (reg_ah & 0x0F) {
        /* TODO: 0x00 = seek to track (in CL) */
        /* TODO: 0x01 = test read? */
        /* TODO: 0x03 = equipment flags? */
        /* TODO: 0x04 = format detect? */
        /* TODO: 0x05 = write disk */
        /* TODO: 0x07 = recalibrate (seek to track 0) */
        /* TODO: 0x0A = Read ID */
        /* TODO: 0x0D = Format track */
        /* TODO: 0x0E = ?? */
        case 0x03: /* equipment flags update (?) */
            // TODO: Update the disk equipment flags in BDA.
            //       For now, make Alantia happy by returning success.
            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x00: /* seek */
            /* CL = track */
            if (floppy == NULL) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }

            if (enable_fdc_timer_hack) {
                // Hack for Ys II
                FDC_WAIT_TIMER_HACK();
            }

            fdc_cyl[drive] = reg_cl;

            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x01: /* test read */
            /* AH bits[4:4] = If set, seek to track specified */
            /* CL           = cylinder (track) */
            /* CH           = sector size (0=128 1=256 2=512 3=1024 etc) */
            /* DL           = sector number (1-based) */
            /* DH           = head */
            /* BX           = size (in bytes) of data to read */
            /* ES:BP        = buffer to read data into */
            if (floppy == NULL) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }
            floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);

            if (enable_fdc_timer_hack) {
                // Hack for Ys II
                FDC_WAIT_TIMER_HACK();
            }

            /* Prevent reading 1.44MB floppyies using 1.2MB read commands and vice versa.
             * FIXME: It seems MS-DOS 5.0 booted from a HDI image has trouble understanding
             *        when Drive A: (the first floppy) is a 1.44MB drive or not and fails
             *        because it only attempts it using 1.2MB format read commands. */
            if (flags & PC98_FLOPPY_RPM_IBMPC) {
                if (img_ssz == 1024) { /* reject 1.2MB 3-mode format */
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }
            }
            else {
                if (img_ssz == 512) { /* reject IBM PC 1.44MB format */
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }
            }

            PC98_BIOS_FDC_CALL_GEO_UNPACK(/*&*/fdc_cyl[drive],/*&*/fdc_head[drive],/*&*/fdc_sect[drive],/*&*/fdc_sz[drive]);
            unitsize = PC98_FDC_SZ_TO_BYTES(fdc_sz[drive]);
            if (0/*unitsize != img_ssz || img_heads == 0 || img_cyl == 0 || img_sect == 0*/) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }

            size = reg_bx;
            while (size > 0) {
                accsize = size > unitsize ? unitsize : size;

                if (floppy->Read_Sector(fdc_head[drive],fdc_cyl[drive],fdc_sect[drive],PC98_BIOS_FLOPPY_BUFFER,unitsize) != 0) {
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }

                size -= accsize;

                if (size == 0) break;

                if ((++fdc_sect[drive]) > img_sect && img_sect != 0) {
                    fdc_sect[drive] = 1;
                    if ((++fdc_head[drive]) >= img_heads && img_heads != 0) {
                        fdc_head[drive] = 0;
                        fdc_cyl[drive]++;
                    }
                }
            }

            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x02: /* read sectors */
        case 0x06: /* read sectors (what's the difference from 0x02?) */
            /* AH bits[4:4] = If set, seek to track specified */
            /* CL           = cylinder (track) */
            /* CH           = sector size (0=128 1=256 2=512 3=1024 etc) */
            /* DL           = sector number (1-based) */
            /* DH           = head */
            /* BX           = size (in bytes) of data to read */
            /* ES:BP        = buffer to read data into */
            if (floppy == NULL) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }
            floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);

            if (enable_fdc_timer_hack) {
                // Hack for Ys II
                FDC_WAIT_TIMER_HACK();
            }

            /* Prevent reading 1.44MB floppyies using 1.2MB read commands and vice versa.
             * FIXME: It seems MS-DOS 5.0 booted from a HDI image has trouble understanding
             *        when Drive A: (the first floppy) is a 1.44MB drive or not and fails
             *        because it only attempts it using 1.2MB format read commands. */
            if (flags & PC98_FLOPPY_RPM_IBMPC) {
                if (img_ssz == 1024) { /* reject 1.2MB 3-mode format */
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }
            }
            else {
                if (img_ssz == 512) { /* reject IBM PC 1.44MB format */
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }
            }

            PC98_BIOS_FDC_CALL_GEO_UNPACK(/*&*/fdc_cyl[drive],/*&*/fdc_head[drive],/*&*/fdc_sect[drive],/*&*/fdc_sz[drive]);
            unitsize = PC98_FDC_SZ_TO_BYTES(fdc_sz[drive]);
            if (0/*unitsize != img_ssz || img_heads == 0 || img_cyl == 0 || img_sect == 0*/) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }

            size = reg_bx;
            memaddr = ((unsigned int)SegValue(es) << 4U) + reg_bp;
            while (size > 0) {
                accsize = size > unitsize ? unitsize : size;

                if (floppy->Read_Sector(fdc_head[drive],fdc_cyl[drive],fdc_sect[drive],PC98_BIOS_FLOPPY_BUFFER,unitsize) != 0) {
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }

                for (unsigned int i=0;i < accsize;i++)
                    mem_writeb(memaddr+i,PC98_BIOS_FLOPPY_BUFFER[i]);

                memaddr += accsize;
                size -= accsize;

                if (size == 0) break;

                if ((++fdc_sect[drive]) > img_sect && img_sect != 0) {
                    fdc_sect[drive] = 1;
                    if ((++fdc_head[drive]) >= img_heads && img_heads != 0) {
                        fdc_head[drive] = 0;
                        fdc_cyl[drive]++;
                    }
                }
            }

            /* need to clear DMA terminal count after read as BIOS would, I assume (Arsys Star Cruiser) */
            {
                DmaChannel *dma = GetDMAChannel(2);
                if (dma) dma->tcount = false;
            }

            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x04: /* drive status */
            status = 0;

            /* TODO: bit 4 is set if write protected */

            if (reg_al & 0x80) { /* high density */
                status |= 0x01;
            }
            else { /* double density */
                /* TODO: */
                status |= 0x01;
            }

            if ((reg_ax & 0x8F40) == 0x8400) {
                status |= 8;        /* 1MB/640KB format, spindle speed for 3-mode */
                if (reg_ah & 0x40) /* DOSBox-X always supports 1.44MB */
                    status |= 4;    /* 1.44MB format, spindle speed for IBM PC format */
            }

            if (floppy == NULL)
                status |= 0xC0;

            reg_ah = status;
            CALLBACK_SCF(false);
            break;
        /* TODO: 0x00 = seek to track (in CL) */
        /* TODO: 0x01 = test read? */
        /* TODO: 0x03 = equipment flags? */
        /* TODO: 0x04 = format detect? */
        /* TODO: 0x05 = write disk */
        /* TODO: 0x07 = recalibrate (seek to track 0) */
        /* TODO: 0x0A = Read ID */
        /* TODO: 0x0D = Format track */
        /* TODO: 0x0E = ?? */
        case 0x05: /* write sectors */
            /* AH bits[4:4] = If set, seek to track specified */
            /* CL           = cylinder (track) */
            /* CH           = sector size (0=128 1=256 2=512 3=1024 etc) */
            /* DL           = sector number (1-based) */
            /* DH           = head */
            /* BX           = size (in bytes) of data to read */
            /* ES:BP        = buffer to write data from */
            if (floppy == NULL) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }
            floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);

            if (enable_fdc_timer_hack) {
                // Hack for Ys II
                FDC_WAIT_TIMER_HACK();
            }

            /* TODO: Error if write protected */

            PC98_BIOS_FDC_CALL_GEO_UNPACK(/*&*/fdc_cyl[drive],/*&*/fdc_head[drive],/*&*/fdc_sect[drive],/*&*/fdc_sz[drive]);
            unitsize = PC98_FDC_SZ_TO_BYTES(fdc_sz[drive]);
            if (0/*unitsize != img_ssz || img_heads == 0 || img_cyl == 0 || img_sect == 0*/) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }

            size = reg_bx;
            memaddr = ((unsigned int)SegValue(es) << 4U) + reg_bp;
            while (size > 0) {
                accsize = size > unitsize ? unitsize : size;

                for (unsigned int i=0;i < accsize;i++)
                    PC98_BIOS_FLOPPY_BUFFER[i] = mem_readb(memaddr+i);

                if (floppy->Write_Sector(fdc_head[drive],fdc_cyl[drive],fdc_sect[drive],PC98_BIOS_FLOPPY_BUFFER,unitsize) != 0) {
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }

                memaddr += accsize;
                size -= accsize;

                if (size == 0) break;

                if ((++fdc_sect[drive]) > img_sect && img_sect != 0) {
                    fdc_sect[drive] = 1;
                    if ((++fdc_head[drive]) >= img_heads && img_heads != 0) {
                        fdc_head[drive] = 0;
                        fdc_cyl[drive]++;
                    }
                }
            }

            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x07: /* recalibrate (seek to track 0) */
            if (floppy == NULL) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }

            if (enable_fdc_timer_hack) {
                // Hack for Ys II
                FDC_WAIT_TIMER_HACK();
            }

            fdc_cyl[drive] = 0;

            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x0D: /* format track */
            if (floppy == NULL) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }

            PC98_BIOS_FDC_CALL_GEO_UNPACK(/*&*/fdc_cyl[drive],/*&*/fdc_head[drive],/*&*/fdc_sect[drive],/*&*/fdc_sz[drive]);
            unitsize = PC98_FDC_SZ_TO_BYTES(fdc_sz[drive]);

            if (enable_fdc_timer_hack) {
                // Hack for Ys II
                FDC_WAIT_TIMER_HACK();
            }

            LOG_MSG("WARNING: INT 1Bh FDC format track command not implemented. Formatting is faked, for now on C/H/S/sz %u/%u/%u/%u drive %c.",
                (unsigned int)fdc_cyl[drive],
                (unsigned int)fdc_head[drive],
                (unsigned int)fdc_sect[drive],
                (unsigned int)unitsize,
                drive + 'A');

            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        case 0x0A: /* read ID */
            /* NTS: PC-98 "MEGDOS" used by some games seems to rely heavily on this call to
             *      verify the floppy head is where it thinks it should be! */
            if (floppy == NULL) {
                CALLBACK_SCF(true);
                reg_ah = 0x00;
                /* TODO? Error code? */
                return;
            }

            floppy->Get_Geometry(&img_heads, &img_cyl, &img_sect, &img_ssz);

            if (enable_fdc_timer_hack) {
                // Hack for Ys II
                FDC_WAIT_TIMER_HACK();
            }

            if (reg_ah & 0x10) { // seek to track number in CL
                if (img_cyl != 0 && reg_cl >= img_cyl) {
                    CALLBACK_SCF(true);
                    reg_ah = 0x00;
                    /* TODO? Error code? */
                    return;
                }

                fdc_cyl[drive] = reg_cl;
            }

            if (fdc_sect[drive] == 0)
                fdc_sect[drive] = 1;

            if (img_ssz >= 1024)
                fdc_sz[drive] = 3;
            else if (img_ssz >= 512)
                fdc_sz[drive] = 2;
            else if (img_ssz >= 256)
                fdc_sz[drive] = 1;
            else
                fdc_sz[drive] = 0;

            reg_cl = fdc_cyl[drive];
            reg_dh = fdc_head[drive];
            reg_dl = fdc_sect[drive];
            /* ^ FIXME: A more realistic emulation would return a random number from 1 to N
             *          where N=sectors/track because the floppy motor is running and tracks
             *          are moving past the head. */
            reg_ch = fdc_sz[drive];

            /* per read ID call, increment the sector through the range on disk.
             * This is REQUIRED or else MEGDOS will not attempt to read this disk. */
            if (img_sect != 0) {
                if ((++fdc_sect[drive]) > img_sect)
                    fdc_sect[drive] = 1;
            }

            reg_ah = 0x00;
            CALLBACK_SCF(false);
            break;
        default:
            LOG_MSG("PC-98 INT 1Bh unknown FDC BIOS call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                    reg_ax,
                    reg_bx,
                    reg_cx,
                    reg_dx,
                    reg_si,
                    reg_di,
                    SegValue(ds),
                    SegValue(es));
            CALLBACK_SCF(true);
            break;
    }
}

static Bitu INT19_PC98_Handler(void) {
    LOG_MSG("PC-98 INT 19h unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
        reg_ax,
        reg_bx,
        reg_cx,
        reg_dx,
        reg_si,
        reg_di,
        SegValue(ds),
        SegValue(es));

    return CBRET_NONE;
}

static Bitu INT1A_PC98_Handler(void) {
    /* HACK: This makes the "test" program in DOSLIB work.
     *       We'll remove this when we implement INT 1Ah */
    if (reg_ax == 0x1000) {
        CALLBACK_SCF(false);
        reg_ax = 0;
    }

    LOG_MSG("PC-98 INT 1Ah unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
        reg_ax,
        reg_bx,
        reg_cx,
        reg_dx,
        reg_si,
        reg_di,
        SegValue(ds),
        SegValue(es));

    return CBRET_NONE;
}

static Bitu INT1B_PC98_Handler(void) {
    /* As BIOS interfaces for disk I/O go, this is fairly unusual */
    switch (reg_al & 0xF0) {
        /* floppy disk access */
        /* AL bits[1:0] = floppy drive number */
        /* Uses INT42 if high density, INT41 if double density */
        /* AH bits[3:0] = command */
        case 0x90: /* 1.2MB HD */
            PC98_BIOS_FDC_CALL(PC98_FLOPPY_HIGHDENSITY|PC98_FLOPPY_2HEAD|PC98_FLOPPY_RPM_3MODE);
            break;
        case 0x30: /* 1.44MB HD (NTS: not supported until the early 1990s) */
        case 0xB0:
            PC98_BIOS_FDC_CALL(PC98_FLOPPY_HIGHDENSITY|PC98_FLOPPY_2HEAD|PC98_FLOPPY_RPM_IBMPC);
            break;
        case 0x70: /* 720KB DD (??) */
        case 0xF0:
            PC98_BIOS_FDC_CALL(PC98_FLOPPY_2HEAD|PC98_FLOPPY_RPM_3MODE); // FIXME, correct??
            break;
        case 0x20: /* SCSI hard disk BIOS */
        case 0xA0: /* SCSI hard disk BIOS */
        case 0x00: /* SASI hard disk BIOS */
        case 0x80: /* SASI hard disk BIOS */
            PC98_BIOS_SCSI_CALL();
            break;
        /* TODO: Other disk formats */
        /* TODO: Future SASI/SCSI BIOS emulation for hard disk images */
        default:
            LOG_MSG("PC-98 INT 1Bh unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                    reg_ax,
                    reg_bx,
                    reg_cx,
                    reg_dx,
                    reg_si,
                    reg_di,
                    SegValue(ds),
                    SegValue(es));
            CALLBACK_SCF(true);
            break;
    }

    return CBRET_NONE;
}

void PC98_Interval_Timer_Continue(void) {
    /* assume: interrupts are disabled */
    IO_WriteB(0x71,0x00);
    // TODO: What time interval is this supposed to be?
    if (PIT_TICK_RATE == PIT_TICK_RATE_PC98_8MHZ)
        IO_WriteB(0x71,0x4E);
    else
        IO_WriteB(0x71,0x60);

    IO_WriteB(0x02,IO_ReadB(0x02) & (~(1u << /*IRQ*/0u))); // unmask IRQ0
}

unsigned char pc98_dec2bcd(unsigned char c) {
    return ((c / 10u) << 4u) + (c % 10u);
}

static Bitu INT1C_PC98_Handler(void) {
    if (reg_ah == 0x00) { /* get time and date */
        time_t curtime;
        const struct tm *loctime;
        curtime = time (NULL);
        loctime = localtime (&curtime);

        unsigned char tmp[6];

        tmp[0] = pc98_dec2bcd((unsigned int)loctime->tm_year % 100u);
        tmp[1] = (((unsigned int)loctime->tm_mon + 1u) << 4u) + (unsigned int)loctime->tm_wday;
        tmp[2] = pc98_dec2bcd(loctime->tm_mday);
        tmp[3] = pc98_dec2bcd(loctime->tm_hour);
        tmp[4] = pc98_dec2bcd(loctime->tm_min);
        tmp[5] = pc98_dec2bcd(loctime->tm_sec);

        unsigned long mem = ((unsigned int)SegValue(es) << 4u) + reg_bx;

        for (unsigned int i=0;i < 6;i++)
            mem_writeb(mem+i,tmp[i]);
    }
    else if (reg_ah == 0x02) { /* set interval timer (single event) */
        /* es:bx = interrupt handler to execute
         * cx = timer interval in ticks (FIXME: what units of time?) */
        mem_writew(0x1C,reg_bx);
        mem_writew(0x1E,SegValue(es));
        mem_writew(0x58A,reg_cx);

        IO_WriteB(0x77,0x36);   /* mode 3, binary, low-byte high-byte 16-bit counter */

        PC98_Interval_Timer_Continue();
    }
    else if (reg_ah == 0x03) { /* continue interval timer */
        PC98_Interval_Timer_Continue();
    }
    /* TODO: According to the PDF at
     *
     * http://hackipedia.org/browse.cgi/Computer/Platform/PC%2c%20NEC%20PC%2d98/Collections/PC%2d9801%20Bible%20%e6%9d%b1%e4%ba%ac%e7%90%86%e7%a7%91%e5%a4%a7%e5%ad%a6EIC%20%281994%29%2epdf
     *
     * There are additional functions
     *
     *  AH = 04h
     *  ES:BX = ?
     *
     *  ---
     *
     *  AH = 05h
     *  ES:BX = ?
     *
     *  ---
     *
     *  AH = 06h
     *  CX = ? (1-FFFFh)
     *  DX = ? (20h-8000h Hz)
     *
     * If any PC-98 games or applications rely on this, let me know. Adding a case for them is easy enough if anyone is interested. --J.C.
     */
    else {
        LOG_MSG("PC-98 INT 1Ch unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                reg_ax,
                reg_bx,
                reg_cx,
                reg_dx,
                reg_si,
                reg_di,
                SegValue(ds),
                SegValue(es));
    }

    return CBRET_NONE;
}

// NTS: According to this PDF, chapter 5, INT 1Dh has additional functions on "High Resolution" PC-98 systems.
//      [https://ia801305.us.archive.org/8/items/PC9800TechnicalDataBookBIOS1992/PC-9800TechnicalDataBook_BIOS_1992_text.pdf]
static Bitu INT1D_PC98_Handler(void) {
    LOG_MSG("PC-98 INT 1Dh unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
        reg_ax,
        reg_bx,
        reg_cx,
        reg_dx,
        reg_si,
        reg_di,
        SegValue(ds),
        SegValue(es));

    return CBRET_NONE;
}

static Bitu INT1E_PC98_Handler(void) {
    LOG_MSG("PC-98 INT 1Eh unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
        reg_ax,
        reg_bx,
        reg_cx,
        reg_dx,
        reg_si,
        reg_di,
        SegValue(ds),
        SegValue(es));

    return CBRET_NONE;
}

void PC98_EXTMEMCPY(void) {
    bool enabled = MEM_A20_Enabled();
    MEM_A20_Enable(true);

    Bitu   bytes    = ((reg_cx - 1u) & 0xFFFFu) + 1u; // bytes, except that 0 == 64KB
    PhysPt data     = SegPhys(es)+reg_bx;
    PhysPt source   = (mem_readd(data+0x12u) & 0x00FFFFFFu) + ((unsigned int)mem_readb(data+0x17u)<<24u);
    PhysPt dest     = (mem_readd(data+0x1Au) & 0x00FFFFFFu) + ((unsigned int)mem_readb(data+0x1Fu)<<24u);

    LOG_MSG("PC-98 memcpy: src=0x%x dst=0x%x data=0x%x count=0x%x",
        (unsigned int)source,(unsigned int)dest,(unsigned int)data,(unsigned int)bytes);

    MEM_BlockCopy(dest,source,bytes);
    MEM_A20_Enable(enabled);
    Segs.limit[cs] = 0xFFFF;
    Segs.limit[ds] = 0xFFFF;
    Segs.limit[es] = 0xFFFF;
    Segs.limit[ss] = 0xFFFF;

    CALLBACK_SCF(false);
}

static Bitu INT1F_PC98_Handler(void) {
    switch (reg_ah) {
        case 0x90:
            /* Copy extended memory */
            PC98_EXTMEMCPY();
            break;
        default:
            LOG_MSG("PC-98 INT 1Fh unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                    reg_ax,
                    reg_bx,
                    reg_cx,
                    reg_dx,
                    reg_si,
                    reg_di,
                    SegValue(ds),
                    SegValue(es));
            CALLBACK_SCF(true);
            break;
    }

    return CBRET_NONE;
}

static Bitu INTGEN_PC98_Handler(void) {
    LOG_MSG("PC-98 INT stub unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
        reg_ax,
        reg_bx,
        reg_cx,
        reg_dx,
        reg_si,
        reg_di,
        SegValue(ds),
        SegValue(es));

    return CBRET_NONE;
}

/* This interrupt should only exist while the DOS kernel is active.
 * On actual PC-98 MS-DOS this is a direct interface to MS-DOS's built-in ANSI CON driver.
 *
 * CL = major function call number
 * AH = minor function call number
 * DX = data?? */
extern bool dos_kernel_disabled;

void PC98_INTDC_WriteChar(unsigned char b);

void INTDC_LOAD_FUNCDEC(pc98_func_key_shortcut_def &def,const Bitu ofs) {
    unsigned int i;

    for (i=0;i < 0x0E;i++)
        def.shortcut[i] = mem_readb(ofs+0x0+i);

    for (i=0;i < 0x0E && def.shortcut[i] != 0;) i++;
    def.length = i;
}

void INTDC_STORE_FUNCDEC(const Bitu ofs,const pc98_func_key_shortcut_def &def) {
    for (unsigned int i=0;i < 0x0E;i++) mem_writeb(ofs+0x0+i,def.shortcut[i]);
    mem_writew(ofs+0xE,0);
}

void INTDC_LOAD_EDITDEC(pc98_func_key_shortcut_def &def,const Bitu ofs) {
    unsigned int i;

    for (i=0;i < 0x05;i++)
        def.shortcut[i] = mem_readb(ofs+0x0+i);

    for (i=0;i < 0x05 && def.shortcut[i] != 0;) i++;
    def.length = i;
}

void INTDC_STORE_EDITDEC(const Bitu ofs,const pc98_func_key_shortcut_def &def) {
    for (unsigned int i=0;i < 0x05;i++) mem_writeb(ofs+0x0+i,def.shortcut[i]);
    mem_writew(ofs+0x5,0);
}

bool inhibited_ControlFn(void) {
    return real_readb(0x60,0x10C) & 0x01;
}

extern bool dos_kernel_disabled;

static const char *fneditkeys[11] = {
    "ROLLUP",
    "ROLLDOWN",
    "INS",
    "DEL",
    "UPARROW",
    "LEFTARROW",
    "RIGHTARROW",
    "DOWNARROW",
    "HOMECLR",
    "HELP",
    "KEYPAD-"
};

void DEBUG_INTDC_FnKeyMapInfo(void) {
    if (!IS_PC98_ARCH) {
        DEBUG_ShowMsg("INT DCh has no meaning except in PC-98 mode");
    }
    else if (dos_kernel_disabled) {
        DEBUG_ShowMsg("INT DCh FnKey mapping has no meaning outside the DOS environment");
    }
    else {
        DEBUG_ShowMsg("INT DCh FnKey mapping. Ctrl+Fn builtin inhibited=%s",inhibited_ControlFn()?"yes":"no");
        for (unsigned int i=0;i < 10;i++)
            DEBUG_ShowMsg("  F%u: %s",i+1,pc98_func_key[i].debugToString().c_str());
        for (unsigned int i=0;i < 5;i++)
            DEBUG_ShowMsg("  VF%u: %s",i+1,pc98_vfunc_key[i].debugToString().c_str());

        for (unsigned int i=0;i < 10;i++)
            DEBUG_ShowMsg("  Shift+F%u: %s",i+1,pc98_func_key_shortcut[i].debugToString().c_str());
        for (unsigned int i=0;i < 5;i++)
            DEBUG_ShowMsg("  Shift+VF%u: %s",i+1,pc98_vfunc_key_shortcut[i].debugToString().c_str());

        for (unsigned int i=0;i < 10;i++)
            DEBUG_ShowMsg("  Control+F%u: %s",i+1,pc98_func_key_ctrl[i].debugToString().c_str());
        for (unsigned int i=0;i < 5;i++)
            DEBUG_ShowMsg("  Control+VF%u: %s",i+1,pc98_vfunc_key_ctrl[i].debugToString().c_str());

        for (unsigned int i=0;i < 11;i++)
            DEBUG_ShowMsg("  %s: %s",fneditkeys[i],pc98_editor_key_escapes[i].debugToString().c_str());
    }
}

/* PC-98 application notes, that are NOT DOSBox-X bugs because they occur on real MS-DOS as well:
 *
 * VZ.COM - If the function key row was hidden when VZ.COM is started, VZ.COM will not restore the
 *          function key row. VZ.COM's function key shortcuts affect Fn and Shift+Fn keys and the
 *          text they display even if VZ.COM also disables the Ctrl+F7 shortcut that lets you
 *          toggle the function key row, which makes displaying the Shift+Fn key shortcuts impossible
 *          unless the function key row was left showing that at startup.
 */

static Bitu INTDC_PC98_Handler(void) {
    if (dos_kernel_disabled) goto unknown;

    switch (reg_cl) {
        case 0x0C: /* CL=0x0C General entry point to read function key state */
            if (reg_ax == 0xFF) { /* Extended version of the API when AX == 0, DS:DX = data to store to */
                /* DS:DX contains
                 *       16*10 bytes, 16 bytes per entry for function keys F1-F10
                 *       16*5 bytes, 16 bytes per entry for VF1-VF5
                 *       16*10 bytes, 16 bytes per entry for function key shortcuts Shift+F1 to Shift+F10
                 *       16*5 bytes, 16 bytes per entry for shift VF1-VF5
                 *       6*11 bytes, 6 bytes per entry for editor keys
                 *       16*10 bytes, 16 bytes per entry for function key shortcuts Control+F1 to Control+F10
                 *       16*5 bytes, 16 bytes per entry for control VF1-VF5
                 *
                 * For whatever reason, the buffer is copied to the DOS buffer +1, meaning that on write it skips the 0x08 byte. */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;

                /* function keys F1-F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_func_key[f]);
                /* VF1-VF5 */
                for (unsigned int f=0;f < 5;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_vfunc_key[f]);
                /* function keys Shift+F1 - Shift+F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_func_key_shortcut[f]);
                /* VF1-VF5 */
                for (unsigned int f=0;f < 5;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_vfunc_key_shortcut[f]);
                /* editor keys */
                for (unsigned int f=0;f < 11;f++,ofs += 6)
                    INTDC_STORE_EDITDEC(ofs,pc98_editor_key_escapes[f]);
                /* function keys Control+F1 - Control+F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_func_key_ctrl[f]);
                /* VF1-VF5 */
                for (unsigned int f=0;f < 5;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_vfunc_key_ctrl[f]);
 
                goto done;
            }
            /* NTS: According to a translation table in the MS-DOS kernel, where
             *      AX=1h to AX=29h inclusive look up from this 0x29-element table:
             *
             *      Table starts with AX=1h, ends with AX=29h
             *
             *                    01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10
             *                     |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
             *      0ADC:00003DE0 01 02 03 04 05 06 07 08 09 0A 10 11 12 13 14 15  ................
             *      0ADC:00003DF0 16 17 18 19 1F 20 21 22 23 24 25 26 27 28 29 0B  ..... !"#$%&'().
             *      0ADC:00003E00 0C 0D 0E 0F 1A 1B 1C 1D 1E|
             *
             *      The table is read, then the byte is decremented by one.
             *
             *      If the result of that is less than 0x1E, it's an index into
             *      the 16 byte/entry Fn key table.
             *
             *      If the result is 0x1E or larger, then (result - 0x1E) is an
             *      index into the editor table, 8 bytes/entry.
             *
             *      Meanings:
             *
             *                    01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10
             *                     |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
             *      0ADC:00003DE0 01 02 03 04 05 06 07 08 09 0A 10 11 12 13 14 15  ................
             *                   | --- Function keys F1-F10 ---| Fn shift F1-F6 -
             *      0ADC:00003DF0 16 17 18 19 1F 20 21 22 23 24 25 26 27 28 29 0B  ..... !"#$%&'().
             *                   | Sh F7-F10 | ------- EDITOR KEYS -----------| -
             *      0ADC:00003E00 0C 0D 0E 0F 1A 1B 1C 1D 1E|
             *                   | --------- | ------------ |
             */
            else if (reg_ax >= 0x01 && reg_ax <= 0x0A) { /* Read individual function keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_STORE_FUNCDEC(ofs,pc98_func_key[reg_ax - 0x01]);
                goto done;
            }
            else if (reg_ax >= 0x0B && reg_ax <= 0x14) { /* Read individual shift + function keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_STORE_FUNCDEC(ofs,pc98_func_key_shortcut[reg_ax - 0x0B]);
                goto done;
            }
            else if (reg_ax >= 0x15 && reg_ax <= 0x1F) { /* Read individual editor keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_STORE_EDITDEC(ofs,pc98_editor_key_escapes[reg_ax - 0x15]);
                goto done;
            }
            else if (reg_ax >= 0x20 && reg_ax <= 0x24) { /* Read VF1-VF5 keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_STORE_FUNCDEC(ofs,pc98_vfunc_key[reg_ax - 0x20]);
                goto done;
            }
            else if (reg_ax >= 0x25 && reg_ax <= 0x29) { /* Read shift VF1-VF5 keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_STORE_FUNCDEC(ofs,pc98_vfunc_key_shortcut[reg_ax - 0x25]);
                goto done;
            }
            else if (reg_ax >= 0x2A && reg_ax <= 0x33) { /* Read individual function keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_STORE_FUNCDEC(ofs,pc98_func_key_ctrl[reg_ax - 0x2A]);
                goto done;
            }
            else if (reg_ax >= 0x34 && reg_ax <= 0x38) { /* Read control VF1-VF5 keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_STORE_FUNCDEC(ofs,pc98_vfunc_key_ctrl[reg_ax - 0x34]);
                goto done;
            }
            else if (reg_ax == 0x00) { /* Read all state, DS:DX = data to store to */
                /* DS:DX contains
                 *       16*10 bytes, 16 bytes per entry for function keys F1-F10
                 *       16*10 bytes, 16 bytes per entry for function key shortcuts Shift+F1 to Shift+F10
                 *       6*11 bytes, 6 bytes per entry of unknown relevence (GUESS: Escapes for other keys like INS, DEL?)
                 *
                 * For whatever reason, the buffer is copied to the DOS buffer +1, meaning that on write it skips the 0x08 byte. */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;

                /* function keys F1-F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_func_key[f]);
                /* function keys Shift+F1 - Shift+F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_STORE_FUNCDEC(ofs,pc98_func_key_shortcut[f]);
                /* editor keys */
                for (unsigned int f=0;f < 11;f++,ofs += 6)
                    INTDC_STORE_EDITDEC(ofs,pc98_editor_key_escapes[f]);

                goto done;
            }
            goto unknown;
        case 0x0D: /* CL=0x0D General entry point to set function key state */
            if (reg_ax == 0xFF) { /* Extended version of the API when AX == 0, DS:DX = data to set */
                /* DS:DX contains
                 *       16*10 bytes, 16 bytes per entry for function keys F1-F10
                 *       16*5 bytes, 16 bytes per entry for VF1-VF5
                 *       16*10 bytes, 16 bytes per entry for function key shortcuts Shift+F1 to Shift+F10
                 *       16*5 bytes, 16 bytes per entry for shift VF1-VF5
                 *       6*11 bytes, 6 bytes per entry for editor keys
                 *       16*10 bytes, 16 bytes per entry for function key shortcuts Control+F1 to Control+F10
                 *       16*5 bytes, 16 bytes per entry for control VF1-VF5
                 *
                 * For whatever reason, the buffer is copied to the DOS buffer +1, meaning that on write it skips the 0x08 byte. */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;

                /* function keys F1-F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_func_key[f],ofs);
                /* VF1-VF5 */
                for (unsigned int f=0;f < 5;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_vfunc_key[f],ofs);
                /* function keys Shift+F1 - Shift+F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_func_key_shortcut[f],ofs);
                /* Shift+VF1 - Shift+VF5 */
                for (unsigned int f=0;f < 5;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_vfunc_key_shortcut[f],ofs);
                /* editor keys */
                for (unsigned int f=0;f < 11;f++,ofs += 6)
                    INTDC_LOAD_EDITDEC(pc98_editor_key_escapes[f],ofs);
                /* function keys Control+F1 - Control+F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_func_key_ctrl[f],ofs);
                /* Shift+VF1 - Shift+VF5 */
                for (unsigned int f=0;f < 5;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_vfunc_key_ctrl[f],ofs);
 
                update_pc98_function_row(pc98_function_row_mode,true);
                goto done;
            }
            else if (reg_ax >= 0x01 && reg_ax <= 0x0A) { /* Read individual function keys, DS:DX = data to set */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_LOAD_FUNCDEC(pc98_func_key[reg_ax - 0x01],ofs);
                goto done;
            }
            else if (reg_ax >= 0x0B && reg_ax <= 0x14) { /* Read individual shift + function keys, DS:DX = data to set */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_LOAD_FUNCDEC(pc98_func_key_shortcut[reg_ax - 0x0B],ofs);
                goto done;
            }
            else if (reg_ax >= 0x15 && reg_ax <= 0x1F) { /* Read individual editor keys, DS:DX = data to set */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_LOAD_EDITDEC(pc98_editor_key_escapes[reg_ax - 0x15],ofs);
                goto done;
            }
            else if (reg_ax >= 0x20 && reg_ax <= 0x24) { /* Read VF1-VF5 keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_LOAD_FUNCDEC(pc98_vfunc_key[reg_ax - 0x20],ofs);
                goto done;
            }
            else if (reg_ax >= 0x25 && reg_ax <= 0x29) { /* Read shift VF1-VF5 keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_LOAD_FUNCDEC(pc98_vfunc_key_shortcut[reg_ax - 0x25],ofs);
                goto done;
            }
            else if (reg_ax >= 0x2A && reg_ax <= 0x33) { /* Read individual function keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_LOAD_FUNCDEC(pc98_func_key_ctrl[reg_ax - 0x2A],ofs);
                goto done;
            }
            else if (reg_ax >= 0x34 && reg_ax <= 0x38) { /* Read control VF1-VF5 keys, DS:DX = data to store to */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;
                INTDC_LOAD_FUNCDEC(pc98_vfunc_key_ctrl[reg_ax - 0x34],ofs);
                goto done;
            }
            else if (reg_ax == 0x00) { /* Read all state, DS:DX = data to set */
                /* DS:DX contains
                 *       16*10 bytes, 16 bytes per entry for function keys F1-F10
                 *       16*10 bytes, 16 bytes per entry for function key shortcuts Shift+F1 to Shift+F10
                 *       6*11 bytes, 6 bytes per entry of editor keys (INS, DEL, etc) that match a specific scan code range
                 *
                 * For whatever reason, the buffer is copied to the DOS buffer +1, meaning that on write it skips the 0x08 byte. */
                Bitu ofs = (Bitu)(SegValue(ds) << 4ul) + (Bitu)reg_dx;

                /* function keys F1-F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_func_key[f],ofs);
                /* function keys Shift+F1 - Shift+F10 */
                for (unsigned int f=0;f < 10;f++,ofs += 16)
                    INTDC_LOAD_FUNCDEC(pc98_func_key_shortcut[f],ofs);
                /* editor keys */
                for (unsigned int f=0;f < 11;f++,ofs += 6)
                    INTDC_LOAD_EDITDEC(pc98_editor_key_escapes[f],ofs);

                update_pc98_function_row(pc98_function_row_mode,true);
                goto done;
            }
            goto unknown;
        case 0x0F:
            if (reg_ax == 0) { /* inhibit Control+Fn shortcuts */
                real_writeb(0x60,0x10C,real_readb(0x60,0x10C) | 0x01);
                goto done;
            }
            else if (reg_ax == 1) { /* enable Control+Fn shortcuts */
                real_writeb(0x60,0x10C,real_readb(0x60,0x10C) & (~0x01));
                goto done;
            }
            goto unknown;
        case 0x10:
            if (reg_ah == 0x00) { /* CL=0x10 AH=0x00 DL=char write char to CON */
                PC98_INTDC_WriteChar(reg_dl);
                goto done;
            }
            else if (reg_ah == 0x01) { /* CL=0x10 AH=0x01 DS:DX write string to CON */
                /* According to the example at http://tepe.tec.fukuoka-u.ac.jp/HP98/studfile/grth/gt10.pdf
                 * the string ends in '$' just like the main DOS string output function. */
                Bit16u ofs = reg_dx;
                do {
                    unsigned char c = real_readb(SegValue(ds),ofs++);
                    if (c == '$') break;
                    PC98_INTDC_WriteChar(c);
                } while (1);
                goto done;
            }
            else if (reg_ah == 0x02) { /* CL=0x10 AH=0x02 DL=attribute set console output attribute */
                /* Ref: https://nas.jmc/jmcs/docs/browse/Computer/Platform/PC%2c%20NEC%20PC%2d98/Collections/Undocumented%209801%2c%209821%20Volume%202%20%28webtech.co.jp%29%20English%20translation/memdos%2eenglish%2dgoogle%2dtranslate%2etxt
                 *
                 * DL is the attribute byte (in the format written directly to video RAM, not the ANSI code)
                 *
                 * NTS: Reverse engineering INT DCh shows it sets both 71Dh and 73Ch as below */
                mem_writeb(0x71D,reg_dl);   /* 60:11D */
                mem_writeb(0x73C,reg_dx);   /* 60:13C */
                goto done;
            }
            else if (reg_ah == 0x03) { /* CL=0x10 AH=0x03 DL=X-coord DH=Y-coord set cursor position */
                void INTDC_CL10h_AH03h(Bit16u raw);
                INTDC_CL10h_AH03h(reg_dx);
                goto done;
            }
            else if (reg_ah == 0x04) { /* CL=0x10 AH=0x04 Move cursor down one line */
                void INTDC_CL10h_AH04h(void);
                INTDC_CL10h_AH04h();
                goto done;
            }
            else if (reg_ah == 0x05) { /* CL=0x10 AH=0x05 Move cursor up one line */
                void INTDC_CL10h_AH05h(void);
                INTDC_CL10h_AH05h();
                goto done;
            }
            else if (reg_ah == 0x06) { /* CL=0x10 AH=0x06 DX=count Move cursor up multiple lines */
                void INTDC_CL10h_AH06h(Bit16u count);
                INTDC_CL10h_AH06h(reg_dx);
                goto done;
            }
            else if (reg_ah == 0x07) { /* CL=0x10 AH=0x07 DX=count Move cursor down multiple lines */
                void INTDC_CL10h_AH07h(Bit16u count);
                INTDC_CL10h_AH07h(reg_dx);
                goto done;
            }
            else if (reg_ah == 0x08) { /* CL=0x10 AH=0x08 DX=count Move cursor right multiple lines */
                void INTDC_CL10h_AH08h(Bit16u count);
                INTDC_CL10h_AH08h(reg_dx);
                goto done;
            }
            else if (reg_ah == 0x09) { /* CL=0x10 AH=0x09 DX=count Move cursor left multiple lines */
                void INTDC_CL10h_AH09h(Bit16u count);
                INTDC_CL10h_AH09h(reg_dx);
                goto done;
            }
            goto unknown;
        default: /* some compilers don't like not having a default case */
            goto unknown;
    }

done:
    return CBRET_NONE;

unknown:
    LOG_MSG("PC-98 INT DCh unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
        reg_ax,
        reg_bx,
        reg_cx,
        reg_dx,
        reg_si,
        reg_di,
        SegValue(ds),
        SegValue(es));

    return CBRET_NONE;
}

static Bitu INTF2_PC98_Handler(void) {
    LOG_MSG("PC-98 INT F2h unknown call AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
        reg_ax,
        reg_bx,
        reg_cx,
        reg_dx,
        reg_si,
        reg_di,
        SegValue(ds),
        SegValue(es));

    return CBRET_NONE;
}

// for more information see [https://ia801305.us.archive.org/8/items/PC9800TechnicalDataBookBIOS1992/PC-9800TechnicalDataBook_BIOS_1992_text.pdf]
static Bitu PC98_BIOS_LIO(void) {
    const char *call_name = "?";

    switch (reg_al) {
        case 0xA0: // GINIT
            call_name = "GINIT";
            goto unknown;
        case 0xA1: // GSCREEN
            call_name = "GSCREEN";
            goto unknown;
        case 0xA2: // GVIEW
            call_name = "GVIEW";
            goto unknown;
        case 0xA3: // GCOLOR1
            call_name = "GCOLOR1";
            goto unknown;
        case 0xA4: // GCOLOR2
            call_name = "GCOLOR2";
            goto unknown;
        case 0xA5: // GCLS
            call_name = "GCLS";
            goto unknown;
        case 0xA6: // GPSET
            call_name = "GPSET";
            goto unknown;
        case 0xA7: // GLINE
            call_name = "GLINE";
            goto unknown;
        case 0xA8: // GCIRCLE
            call_name = "GCIRCLE";
            goto unknown;
        case 0xA9: // GPAINT1
            call_name = "GPAINT1";
            goto unknown;
        case 0xAA: // GPAINT2
            call_name = "GPAINT2";
            goto unknown;
        case 0xAB: // GGET
            call_name = "GGET";
            goto unknown;
        case 0xAC: // GPUT1
            call_name = "GPUT1";
            goto unknown;
        case 0xAD: // GPUT2
            call_name = "GPUT2";
            goto unknown;
        case 0xAE: // GROLL
            call_name = "GROLL";
            goto unknown;
        case 0xAF: // GPOINT2
            call_name = "GPOINT2";
            goto unknown;
        case 0xCE: // GCOPY
            call_name = "GCOPY";
            goto unknown;
        case 0x00: // GRAPH BIO
            call_name = "GRAPH BIO";
            goto unknown;
        default:
        unknown:
            /* on entry, AL (from our BIOS code) is set to the call number that lead here */
                LOG_MSG("PC-98 BIOS LIO graphics call 0x%02x '%s' with AX=%04X BX=%04X CX=%04X DX=%04X SI=%04X DI=%04X DS=%04X ES=%04X",
                        reg_al,
                        call_name,
                        reg_ax,
                        reg_bx,
                        reg_cx,
                        reg_dx,
                        reg_si,
                        reg_di,
                        SegValue(ds),
                        SegValue(es));
                break;
    };

    // from Yksoft1's patch
    reg_ah = 0;

    return CBRET_NONE;
}

static Bitu INT11_Handler(void) {
    reg_ax=mem_readw(BIOS_CONFIGURATION);
    return CBRET_NONE;
}
/* 
 * Define the following define to 1 if you want dosbox to check 
 * the system time every 5 seconds and adjust 1/2 a second to sync them.
 */
#ifndef DOSBOX_CLOCKSYNC
#define DOSBOX_CLOCKSYNC 0
#endif

static void BIOS_HostTimeSync() {
    Bit32u milli = 0;
#if defined(DB_HAVE_CLOCK_GETTIME) && ! defined(WIN32)
    struct timespec tp;
    clock_gettime(CLOCK_REALTIME,&tp);
        
    struct tm *loctime;
    loctime = localtime(&tp.tv_sec);
    milli = (Bit32u) (tp.tv_nsec / 1000000);
#else
    /* Setup time and date */
    struct timeb timebuffer;
    ftime(&timebuffer);
    
    const struct tm *loctime;
    loctime = localtime (&timebuffer.time);
    milli = (Bit32u) timebuffer.millitm;
#endif
    /*
    loctime->tm_hour = 23;
    loctime->tm_min = 59;
    loctime->tm_sec = 45;
    loctime->tm_mday = 28;
    loctime->tm_mon = 2-1;
    loctime->tm_year = 2007 - 1900;
    */

    dos.date.day=(Bit8u)loctime->tm_mday;
    dos.date.month=(Bit8u)loctime->tm_mon+1;
    dos.date.year=(Bit16u)loctime->tm_year+1900;

    Bit32u ticks=(Bit32u)(((double)(
        (unsigned int)loctime->tm_hour*3600u*1000u+
        (unsigned int)loctime->tm_min*60u*1000u+
        (unsigned int)loctime->tm_sec*1000u+
        milli))*(((double)PIT_TICK_RATE/65536.0)/1000.0));
    mem_writed(BIOS_TIMER,ticks);
}

// TODO: make option
bool enable_bios_timer_synchronize_keyboard_leds = true;

void KEYBOARD_SetLEDs(Bit8u bits);

void BIOS_KEYBOARD_SetLEDs(Bitu state) {
    Bitu x = mem_readb(BIOS_KEYBOARD_LEDS);

    x &= ~7u;
    x |= (state & 7u);
    mem_writeb(BIOS_KEYBOARD_LEDS,x);
    KEYBOARD_SetLEDs(state);
}

/* PC-98 IRQ 0 system timer */
static Bitu INT8_PC98_Handler(void) {
    Bit16u counter = mem_readw(0x58A) - 1;
    mem_writew(0x58A,counter);

    /* NTS 2018/02/23: I just confirmed from the ROM BIOS of an actual
     *                 PC-98 system that this implementation and Neko Project II
     *                 are 100% accurate to what the BIOS actually does.
     *                 INT 07h really is the "timer tick" interrupt called
     *                 from INT 08h / IRQ 0, and the BIOS really does call
     *                 INT 1Ch AH=3 from INT 08h if the tick count has not
     *                 yet reached zero.
     *
     *                 I'm guessing NEC's BIOS developers invented this prior
     *                 to the Intel 80286 and it's INT 07h
     *                 "Coprocessor not present" exception. */

    if (counter == 0) {
        /* mask IRQ 0 */
        IO_WriteB(0x02,IO_ReadB(0x02) | 0x01);
        /* ack IRQ 0 */
        IO_WriteB(0x00,0x20);
        /* INT 07h */
        CPU_Interrupt(7,CPU_INT_SOFTWARE,reg_eip);
    }
    else {
        /* ack IRQ 0 */
        IO_WriteB(0x00,0x20);
        /* make sure it continues ticking */
        PC98_Interval_Timer_Continue();
    }

    return CBRET_NONE;
}

static Bitu INT8_Handler(void) {
    /* Increase the bios tick counter */
    Bit32u value = mem_readd(BIOS_TIMER) + 1;
    if(value >= 0x1800B0) {
        // time wrap at midnight
        mem_writeb(BIOS_24_HOURS_FLAG,mem_readb(BIOS_24_HOURS_FLAG)+1);
        value=0;
    }

    /* Legacy BIOS behavior: This isn't documented at all but most BIOSes
       check the BIOS data area for LED keyboard status. If it sees that
       value change, then it sends it to the keyboard. This is why on
       older DOS machines you could change LEDs by writing to 40:17.
       We have to emulate this also because Windows 3.1/9x seems to rely on
       it when handling the keyboard from it's own driver. Their driver does
       hook the keyboard and handles keyboard I/O by itself, but it still
       allows the BIOS to do the keyboard magic from IRQ 0 (INT 8h). Yech. */
    if (enable_bios_timer_synchronize_keyboard_leds) {
        Bitu should_be = (mem_readb(BIOS_KEYBOARD_STATE) >> 4) & 7;
        Bitu led_state = (mem_readb(BIOS_KEYBOARD_LEDS) & 7);

        if (should_be != led_state)
            BIOS_KEYBOARD_SetLEDs(should_be);
    }

#if DOSBOX_CLOCKSYNC
    static bool check = false;
    if((value %50)==0) {
        if(((value %100)==0) && check) {
            check = false;
            time_t curtime;struct tm *loctime;
            curtime = time (NULL);loctime = localtime (&curtime);
            Bit32u ticksnu = (Bit32u)((loctime->tm_hour*3600+loctime->tm_min*60+loctime->tm_sec)*(float)PIT_TICK_RATE/65536.0);
            Bit32s bios = value;Bit32s tn = ticksnu;
            Bit32s diff = tn - bios;
            if(diff>0) {
                if(diff < 18) { diff  = 0; } else diff = 9;
            } else {
                if(diff > -18) { diff = 0; } else diff = -9;
            }
         
            value += diff;
        } else if((value%100)==50) check = true;
    }
#endif
    mem_writed(BIOS_TIMER,value);

    /* decrease floppy motor timer */
    Bit8u val = mem_readb(BIOS_DISK_MOTOR_TIMEOUT);
    if (val) mem_writeb(BIOS_DISK_MOTOR_TIMEOUT,val-1);
    /* and running drive */
    mem_writeb(BIOS_DRIVE_RUNNING,mem_readb(BIOS_DRIVE_RUNNING) & 0xF0);
    return CBRET_NONE;
}
#undef DOSBOX_CLOCKSYNC

static Bitu INT1C_Handler(void) {
    return CBRET_NONE;
}

static Bitu INT12_Handler(void) {
    reg_ax=mem_readw(BIOS_MEMORY_SIZE);
    return CBRET_NONE;
}

static Bitu INT17_Handler(void) {
    if (reg_ah > 0x2 || reg_dx > 0x2) { // 0-2 printer port functions
                                        // and no more than 3 parallel ports
        LOG_MSG("BIOS INT17: Unhandled call AH=%2X DX=%4x",reg_ah,reg_dx);
        return CBRET_NONE;
    }

    switch(reg_ah) {
    case 0x00:      // PRINTER: Write Character
        if(parallelPortObjects[reg_dx]!=0) {
            if(parallelPortObjects[reg_dx]->Putchar(reg_al))
                reg_ah=parallelPortObjects[reg_dx]->getPrinterStatus();
            else reg_ah=1;
        }
        break;
    case 0x01:      // PRINTER: Initialize port
        if(parallelPortObjects[reg_dx]!= 0) {
            parallelPortObjects[reg_dx]->initialize();
            reg_ah=parallelPortObjects[reg_dx]->getPrinterStatus();
        }
        break;
    case 0x02:      // PRINTER: Get Status
        if(parallelPortObjects[reg_dx] != 0)
            reg_ah=parallelPortObjects[reg_dx]->getPrinterStatus();
        //LOG_MSG("printer status: %x",reg_ah);
        break;
    }
    return CBRET_NONE;
}

static bool INT14_Wait(Bit16u port, Bit8u mask, Bit8u timeout, Bit8u* retval) {
    double starttime = PIC_FullIndex();
    double timeout_f = timeout * 1000.0;
    while (((*retval = IO_ReadB(port)) & mask) != mask) {
        if (starttime < (PIC_FullIndex() - timeout_f)) {
            return false;
        }
        CALLBACK_Idle();
    }
    return true;
}

static Bitu INT4B_Handler(void) {
    /* TODO: This is where the Virtual DMA specification is accessed on modern systems.
     *       When we implement that, move this to EMM386 emulation code. */

    if (reg_ax >= 0x8102 && reg_ax <= 0x810D) {
        LOG(LOG_MISC,LOG_DEBUG)("Guest OS attempted Virtual DMA specification call (INT 4Bh AX=%04x BX=%04x CX=%04x DX=%04x",
            reg_ax,reg_bx,reg_cx,reg_dx);
    }
    else if (reg_ah == 0x80) {
        LOG(LOG_MISC,LOG_DEBUG)("Guest OS attempted IBM SCSI interface call");
    }
    else if (reg_ah <= 0x02) {
        LOG(LOG_MISC,LOG_DEBUG)("Guest OS attempted TI Professional PC parallel port function AH=%02x",reg_ah);
    }
    else {
        LOG(LOG_MISC,LOG_DEBUG)("Guest OS attempted unknown INT 4Bh call AX=%04x",reg_ax);
    }
    
    /* Oh, I'm just a BIOS that doesn't know what the hell you're doing. CF=1 */
    CALLBACK_SCF(true);
    return CBRET_NONE;
}

static Bitu INT14_Handler(void) {
    if (reg_ah > 0x3 || reg_dx > 0x3) { // 0-3 serial port functions
                                        // and no more than 4 serial ports
        LOG_MSG("BIOS INT14: Unhandled call AH=%2X DX=%4x",reg_ah,reg_dx);
        return CBRET_NONE;
    }
    
    Bit16u port = real_readw(0x40,reg_dx * 2u); // DX is always port number
    Bit8u timeout = mem_readb((PhysPt)((unsigned int)BIOS_COM1_TIMEOUT + (unsigned int)reg_dx));
    if (port==0)    {
        LOG(LOG_BIOS,LOG_NORMAL)("BIOS INT14: port %d does not exist.",reg_dx);
        return CBRET_NONE;
    }
    switch (reg_ah) {
    case 0x00:  {
        // Initialize port
        // Parameters:              Return:
        // AL: port parameters      AL: modem status
        //                          AH: line status

        // set baud rate
        Bitu baudrate = 9600u;
        Bit16u baudresult;
        Bitu rawbaud=(Bitu)reg_al>>5u;
        
        if (rawbaud==0){ baudrate=110u;}
        else if (rawbaud==1){ baudrate=150u;}
        else if (rawbaud==2){ baudrate=300u;}
        else if (rawbaud==3){ baudrate=600u;}
        else if (rawbaud==4){ baudrate=1200u;}
        else if (rawbaud==5){ baudrate=2400u;}
        else if (rawbaud==6){ baudrate=4800u;}
        else if (rawbaud==7){ baudrate=9600u;}

        baudresult = (Bit16u)(115200u / baudrate);

        IO_WriteB(port+3u, 0x80u);    // enable divider access
        IO_WriteB(port, (Bit8u)baudresult&0xffu);
        IO_WriteB(port+1u, (Bit8u)(baudresult>>8u));

        // set line parameters, disable divider access
        IO_WriteB(port+3u, reg_al&0x1Fu); // LCR
        
        // disable interrupts
        IO_WriteB(port+1u, 0u); // IER

        // get result
        reg_ah=IO_ReadB(port+5u)&0xffu;
        reg_al=IO_ReadB(port+6u)&0xffu;
        CALLBACK_SCF(false);
        break;
    }
    case 0x01: // Transmit character
        // Parameters:              Return:
        // AL: character            AL: unchanged
        // AH: 0x01                 AH: line status from just before the char was sent
        //                              (0x80 | unpredicted) in case of timeout
        //                      [undoc] (0x80 | line status) in case of tx timeout
        //                      [undoc] (0x80 | modem status) in case of dsr/cts timeout

        // set DTR & RTS on
        IO_WriteB(port+4u,0x3u);
        // wait for DSR & CTS
        if (INT14_Wait(port+6u, 0x30u, timeout, &reg_ah)) {
            // wait for TX buffer empty
            if (INT14_Wait(port+5u, 0x20u, timeout, &reg_ah)) {
                // fianlly send the character
                IO_WriteB(port,reg_al);
            } else
                reg_ah |= 0x80u;
        } else // timed out
            reg_ah |= 0x80u;

        CALLBACK_SCF(false);
        break;
    case 0x02: // Read character
        // Parameters:              Return:
        // AH: 0x02                 AL: received character
        //                      [undoc] will be trashed in case of timeout
        //                          AH: (line status & 0x1E) in case of success
        //                              (0x80 | unpredicted) in case of timeout
        //                      [undoc] (0x80 | line status) in case of rx timeout
        //                      [undoc] (0x80 | modem status) in case of dsr timeout

        // set DTR on
        IO_WriteB(port+4u,0x1u);

        // wait for DSR
        if (INT14_Wait(port+6, 0x20, timeout, &reg_ah)) {
            // wait for character to arrive
            if (INT14_Wait(port+5, 0x01, timeout, &reg_ah)) {
                reg_ah &= 0x1E;
                reg_al = IO_ReadB(port);
            } else
                reg_ah |= 0x80;
        } else
            reg_ah |= 0x80;

        CALLBACK_SCF(false);
        break;
    case 0x03: // get status
        reg_ah=IO_ReadB(port+5u)&0xffu;
        reg_al=IO_ReadB(port+6u)&0xffu;
        CALLBACK_SCF(false);
        break;

    }
    return CBRET_NONE;
}

Bits HLT_Decode(void);
void KEYBOARD_AUX_Write(Bitu val);
unsigned char KEYBOARD_AUX_GetType();
unsigned char KEYBOARD_AUX_DevStatus();
unsigned char KEYBOARD_AUX_Resolution();
unsigned char KEYBOARD_AUX_SampleRate();
void KEYBOARD_ClrBuffer(void);

static Bitu INT15_Handler(void) {
    if( ( machine==MCH_AMSTRAD ) && ( reg_ah<0x07 ) ) {
        switch(reg_ah) {
            case 0x00:
                // Read/Reset Mouse X/Y Counts.
                // CX = Signed X Count.
                // DX = Signed Y Count.
                // CC.
            case 0x01:
                // Write NVR Location.
                // AL = NVR Address to be written (0-63).
                // BL = NVR Data to be written.

                // AH = Return Code.
                // 00 = NVR Written Successfully.
                // 01 = NVR Address out of range.
                // 02 = NVR Data write error.
                // CC.
            case 0x02:
                // Read NVR Location.
                // AL = NVR Address to be read (0-63).

                // AH = Return Code.
                // 00 = NVR read successfully.
                // 01 = NVR Address out of range.
                // 02 = NVR checksum error.
                // AL = Byte read from NVR.
                // CC.
            default:
                LOG(LOG_BIOS,LOG_NORMAL)("INT15 Unsupported PC1512 Call %02X",reg_ah);
                return CBRET_NONE;
            case 0x03:
                // Write VDU Colour Plane Write Register.
                vga.amstrad.write_plane = reg_al & 0x0F;
                CALLBACK_SCF(false);
                break;
            case 0x04:
                // Write VDU Colour Plane Read Register.
                vga.amstrad.read_plane = reg_al & 0x03;
                CALLBACK_SCF(false);
                break;
            case 0x05:
                // Write VDU Graphics Border Register.
                vga.amstrad.border_color = reg_al & 0x0F;
                CALLBACK_SCF(false);
                break;
            case 0x06:
                // Return ROS Version Number.
                reg_bx = 0x0001;
                CALLBACK_SCF(false);
                break;
        }
    }
    switch (reg_ah) {
    case 0x06:
        LOG(LOG_BIOS,LOG_NORMAL)("INT15 Unkown Function 6 (Amstrad?)");
        break;
    case 0xC0:  /* Get Configuration*/
        CPU_SetSegGeneral(es,biosConfigSeg);
        reg_bx = 0;
        reg_ah = 0;
        CALLBACK_SCF(false);
        break;
    case 0x4f:  /* BIOS - Keyboard intercept */
        /* Carry should be set but let's just set it just in case */
        CALLBACK_SCF(true);
        break;
    case 0x83:  /* BIOS - SET EVENT WAIT INTERVAL */
        {
            if(reg_al == 0x01) { /* Cancel it */
                mem_writeb(BIOS_WAIT_FLAG_ACTIVE,0);
                IO_Write(0x70,0xb);
                IO_Write(0x71,IO_Read(0x71)&~0x40);
                CALLBACK_SCF(false);
                break;
            }
            if (mem_readb(BIOS_WAIT_FLAG_ACTIVE)) {
                reg_ah=0x80;
                CALLBACK_SCF(true);
                break;
            }
            Bit32u count=((Bit32u)reg_cx<<16u)|reg_dx;
            mem_writed(BIOS_WAIT_FLAG_POINTER,RealMake(SegValue(es),reg_bx));
            mem_writed(BIOS_WAIT_FLAG_COUNT,count);
            mem_writeb(BIOS_WAIT_FLAG_ACTIVE,1);
            /* Reprogram RTC to start */
            IO_Write(0x70,0xb);
            IO_Write(0x71,IO_Read(0x71)|0x40);
            CALLBACK_SCF(false);
        }
        break;
    case 0x84:  /* BIOS - JOYSTICK SUPPORT (XT after 11/8/82,AT,XT286,PS) */
        if (reg_dx == 0x0000) {
            // Get Joystick button status
            if (JOYSTICK_IsEnabled(0) || JOYSTICK_IsEnabled(1)) {
                reg_al = IO_ReadB(0x201)&0xf0;
                CALLBACK_SCF(false);
            } else {
                // dos values
                reg_ax = 0x00f0; reg_dx = 0x0201;
                CALLBACK_SCF(true);
            }
        } else if (reg_dx == 0x0001) {
            if (JOYSTICK_IsEnabled(0)) {
                reg_ax = (Bit16u)(JOYSTICK_GetMove_X(0)*127+128);
                reg_bx = (Bit16u)(JOYSTICK_GetMove_Y(0)*127+128);
                if(JOYSTICK_IsEnabled(1)) {
                    reg_cx = (Bit16u)(JOYSTICK_GetMove_X(1)*127+128);
                    reg_dx = (Bit16u)(JOYSTICK_GetMove_Y(1)*127+128);
                }
                else {
                    reg_cx = reg_dx = 0;
                }
                CALLBACK_SCF(false);
            } else if (JOYSTICK_IsEnabled(1)) {
                reg_ax = reg_bx = 0;
                reg_cx = (Bit16u)(JOYSTICK_GetMove_X(1)*127+128);
                reg_dx = (Bit16u)(JOYSTICK_GetMove_Y(1)*127+128);
                CALLBACK_SCF(false);
            } else {            
                reg_ax = reg_bx = reg_cx = reg_dx = 0;
                CALLBACK_SCF(true);
            }
        } else {
            LOG(LOG_BIOS,LOG_ERROR)("INT15:84:Unknown Bios Joystick functionality.");
        }
        break;
    case 0x86:  /* BIOS - WAIT (AT,PS) */
        {
            if (mem_readb(BIOS_WAIT_FLAG_ACTIVE)) {
                reg_ah=0x83;
                CALLBACK_SCF(true);
                break;
            }
            Bit8u t;
            Bit32u count=((Bit32u)reg_cx<<16u)|reg_dx;
            mem_writed(BIOS_WAIT_FLAG_POINTER,RealMake(0,BIOS_WAIT_FLAG_TEMP));
            mem_writed(BIOS_WAIT_FLAG_COUNT,count);
            mem_writeb(BIOS_WAIT_FLAG_ACTIVE,1);

            /* if the user has not set the option, warn if IRQs are masked */
            if (!int15_wait_force_unmask_irq) {
                /* make sure our wait function works by unmasking IRQ 2, and IRQ 8.
                 * (bugfix for 1993 demo Yodel "Mayday" demo. this demo keeps masking IRQ 2 for some stupid reason.) */
                if ((t=IO_Read(0x21)) & (1 << 2)) {
                    LOG(LOG_BIOS,LOG_ERROR)("INT15:86:Wait: IRQ 2 masked during wait. "
                        "Consider adding 'int15 wait force unmask irq=true' to your dosbox.conf");
                }
                if ((t=IO_Read(0xA1)) & (1 << 0)) {
                    LOG(LOG_BIOS,LOG_ERROR)("INT15:86:Wait: IRQ 8 masked during wait. "
                        "Consider adding 'int15 wait force unmask irq=true' to your dosbox.conf");
                }
            }

            /* Reprogram RTC to start */
            IO_Write(0x70,0xb);
            IO_Write(0x71,IO_Read(0x71)|0x40);
            while (mem_readd(BIOS_WAIT_FLAG_COUNT)) {
                if (int15_wait_force_unmask_irq) {
                    /* make sure our wait function works by unmasking IRQ 2, and IRQ 8.
                     * (bugfix for 1993 demo Yodel "Mayday" demo. this demo keeps masking IRQ 2 for some stupid reason.) */
                    if ((t=IO_Read(0x21)) & (1 << 2)) {
                        LOG(LOG_BIOS,LOG_WARN)("INT15:86:Wait: IRQ 2 masked during wait. "
                            "This condition might result in an infinite wait on "
                            "some BIOSes. Unmasking IRQ to keep things moving along.");
                        IO_Write(0x21,t & ~(1 << 2));

                    }
                    if ((t=IO_Read(0xA1)) & (1 << 0)) {
                        LOG(LOG_BIOS,LOG_WARN)("INT15:86:Wait: IRQ 8 masked during wait. "
                            "This condition might result in an infinite wait on some "
                            "BIOSes. Unmasking IRQ to keep things moving along.");
                        IO_Write(0xA1,t & ~(1 << 0));
                    }
                }

                CALLBACK_Idle();
            }
            CALLBACK_SCF(false);
            break;
        }
    case 0x87:  /* Copy extended memory */
        {
            bool enabled = MEM_A20_Enabled();
            MEM_A20_Enable(true);
            Bitu   bytes    = reg_cx * 2u;
            PhysPt data     = SegPhys(es)+reg_si;
            PhysPt source   = (mem_readd(data+0x12u) & 0x00FFFFFFu) + ((unsigned int)mem_readb(data+0x17u)<<24u);
            PhysPt dest     = (mem_readd(data+0x1Au) & 0x00FFFFFFu) + ((unsigned int)mem_readb(data+0x1Fu)<<24u);
            MEM_BlockCopy(dest,source,bytes);
            reg_ax = 0x00;
            MEM_A20_Enable(enabled);
            Segs.limit[cs] = 0xFFFF;
            Segs.limit[ds] = 0xFFFF;
            Segs.limit[es] = 0xFFFF;
            Segs.limit[ss] = 0xFFFF;
            CALLBACK_SCF(false);
            break;
        }   
    case 0x88:  /* SYSTEM - GET EXTENDED MEMORY SIZE (286+) */
        /* This uses the 16-bit value read back from CMOS which is capped at 64MB */
        reg_ax=other_memsystems?0:size_extended;
        LOG(LOG_BIOS,LOG_NORMAL)("INT15:Function 0x88 Remaining %04X kb",reg_ax);
        CALLBACK_SCF(false);
        break;
    case 0x89:  /* SYSTEM - SWITCH TO PROTECTED MODE */
        {
            IO_Write(0x20,0x10);IO_Write(0x21,reg_bh);IO_Write(0x21,0);IO_Write(0x21,0xFF);
            IO_Write(0xA0,0x10);IO_Write(0xA1,reg_bl);IO_Write(0xA1,0);IO_Write(0xA1,0xFF);
            MEM_A20_Enable(true);
            PhysPt table=SegPhys(es)+reg_si;
            CPU_LGDT(mem_readw(table+0x8),mem_readd(table+0x8+0x2) & 0xFFFFFF);
            CPU_LIDT(mem_readw(table+0x10),mem_readd(table+0x10+0x2) & 0xFFFFFF);
            CPU_SET_CRX(0,CPU_GET_CRX(0)|1);
            CPU_SetSegGeneral(ds,0x18);
            CPU_SetSegGeneral(es,0x20);
            CPU_SetSegGeneral(ss,0x28);
            Bitu ret = mem_readw(SegPhys(ss)+reg_sp);
            reg_sp+=6;          //Clear stack of interrupt frame
            CPU_SetFlags(0,FMASK_ALL);
            reg_ax=0;
            CPU_JMP(false,0x30,ret,0);
        }
        break;
    case 0x8A:  /* EXTENDED MEMORY SIZE */
        {
            Bitu sz = MEM_TotalPages()*4;
            if (sz >= 1024) sz -= 1024;
            else sz = 0;
            reg_ax = sz & 0xFFFF;
            reg_dx = sz >> 16;
            CALLBACK_SCF(false);
        }
        break;
    case 0x90:  /* OS HOOK - DEVICE BUSY */
        CALLBACK_SCF(false);
        reg_ah=0;
        break;
    case 0x91:  /* OS HOOK - DEVICE POST */
        CALLBACK_SCF(false);
        reg_ah=0;
        break;
    case 0xc2:  /* BIOS PS2 Pointing Device Support */
            /* TODO: Our reliance on AUX emulation means that at some point, AUX emulation
             *       must always be enabled if BIOS PS/2 emulation is enabled. Future planned change:
             *
             *       If biosps2=true and aux=true, carry on what we're already doing now: emulate INT 15h by
             *         directly writing to the AUX port of the keyboard controller.
             *
             *       If biosps2=false, the aux= setting enables/disables AUX emulation as it already does now.
             *         biosps2=false implies that we're emulating a keyboard controller with AUX but no BIOS
             *         support for it (however rare that might be). This gives the user of DOSBox-X the means
             *         to test that scenario especially in case he/she is developing a homebrew OS and needs
             *         to ensure their code can handle cases like that gracefully.
             *
             *       If biosps2=true and aux=false, AUX emulation is enabled anyway, but the keyboard emulation
             *         must act as if the AUX port is not there so the guest OS cannot control it. Again, not
             *         likely on real hardware, but a useful test case for homebrew OS developers.
             *
             *       If you the user set aux=false, then you obviously want to test a system configuration
             *       where the keyboard controller has no AUX port. If you set biosps2=true, then you want to
             *       test an OS that uses BIOS functions to setup the "pointing device" but you do not want the
             *       guest OS to talk directly to the AUX port on the keyboard controller.
             *
             *       Logically that's not likely to happen on real hardware, but we like giving the end-user
             *       options to play with, so instead, if aux=false and biosps2=true, DOSBox-X should print
             *       a warning stating that INT 15h mouse emulation with a PS/2 port is nonstandard and may
             *       cause problems with OSes that need to talk directly to hardware.
             *
             *       It is noteworthy that PS/2 mouse support in MS-DOS mouse drivers as well as Windows 3.x,
             *       Windows 95, and Windows 98, is carried out NOT by talking directly to the AUX port but
             *       instead by relying on the BIOS INT 15h functions here to do the dirty work. For those
             *       scenarios, biosps2=true and aux=false is perfectly safe and does not cause issues.
             *
             *       OSes that communicate directly with the AUX port however (Linux, Windows NT) will not work
             *       unless aux=true. */
        if (en_bios_ps2mouse) {
//          LOG_MSG("INT 15h AX=%04x BX=%04x\n",reg_ax,reg_bx);
            switch (reg_al) {
                case 0x00:      // enable/disable
                    if (reg_bh==0) {    // disable
                        KEYBOARD_AUX_Write(0xF5);
                        Mouse_SetPS2State(false);
                        reg_ah=0;
                        CALLBACK_SCF(false);
                        KEYBOARD_ClrBuffer();
                    } else if (reg_bh==0x01) {  //enable
                        if (!Mouse_SetPS2State(true)) {
                            reg_ah=5;
                            CALLBACK_SCF(true);
                            break;
                        }
                        KEYBOARD_AUX_Write(0xF4);
                        KEYBOARD_ClrBuffer();
                        reg_ah=0;
                        CALLBACK_SCF(false);
                    } else {
                        CALLBACK_SCF(true);
                        reg_ah=1;
                    }
                    break;
                case 0x01:      // reset
                    KEYBOARD_AUX_Write(0xFF);
                    Mouse_SetPS2State(false);
                    KEYBOARD_ClrBuffer();
                    reg_bx=0x00aa;  // mouse
                    // fall through
                case 0x05:      // initialize
                    if (reg_bh >= 3 && reg_bh <= 4) {
                        /* TODO: BIOSes remember this value as the number of bytes to store before
                         *       calling the device callback. Setting this value to "1" is perfectly
                         *       valid if you want a byte-stream like mode (at the cost of one
                         *       interrupt per byte!). Most OSes will call this with BH=3 for standard
                         *       PS/2 mouse protocol. You can also call this with BH=4 for Intellimouse
                         *       protocol support, though testing (so far with VirtualBox) shows the
                         *       device callback still only gets the first three bytes on the stack.
                         *       Contrary to what you might think, the BIOS does not interpret the
                         *       bytes at all.
                         *
                         *       The source code of CuteMouse 1.9 seems to suggest some BIOSes take
                         *       pains to repack the 4th byte in the upper 8 bits of one of the WORDs
                         *       on the stack in Intellimouse mode at the cost of shifting the W and X
                         *       fields around. I can't seem to find any source on who does that or
                         *       if it's even true, so I disregard the example at this time.
                         *
                         *       Anyway, you need to store off this value somewhere and make use of
                         *       it in src/ints/mouse.cpp device callback emulation to reframe the
                         *       PS/2 mouse bytes coming from AUX (if aux=true) or emulate the
                         *       re-framing if aux=false to emulate this protocol fully. */
                        LOG_MSG("INT 15h mouse initialized to %u-byte protocol\n",reg_bh);
                        KEYBOARD_AUX_Write(0xF6); /* set defaults */
                        Mouse_SetPS2State(false);
                        KEYBOARD_ClrBuffer();
                        CALLBACK_SCF(false);
                        reg_ah=0;
                    }
                    else {
                        CALLBACK_SCF(false);
                        reg_ah=0x02; /* invalid input */
                    }
                    break;
                case 0x02: {        // set sampling rate
                    static const unsigned char tbl[7] = {10,20,40,60,80,100,200};
                    KEYBOARD_AUX_Write(0xF3);
                    if (reg_bl > 6) reg_bl = 6;
                    KEYBOARD_AUX_Write(tbl[reg_bh]);
                    KEYBOARD_ClrBuffer();
                    CALLBACK_SCF(false);
                    reg_ah=0;
                    } break;
                case 0x03:      // set resolution
                    KEYBOARD_AUX_Write(0xE8);
                    KEYBOARD_AUX_Write(reg_bh&3);
                    KEYBOARD_ClrBuffer();
                    CALLBACK_SCF(false);
                    reg_ah=0;
                    break;
                case 0x04:      // get type
                    reg_bh=KEYBOARD_AUX_GetType();  // ID
                    LOG_MSG("INT 15h reporting mouse device ID 0x%02x\n",reg_bh);
                    KEYBOARD_ClrBuffer();
                    CALLBACK_SCF(false);
                    reg_ah=0;
                    break;
                case 0x06:      // extended commands
                    if (reg_bh == 0x00) {
                        /* Read device status and info.
                         * Windows 9x does not appear to use this, but Windows NT 3.1 does (prior to entering
                         * full 32-bit protected mode) */
                        CALLBACK_SCF(false);
                        reg_bx=KEYBOARD_AUX_DevStatus();
                        reg_cx=KEYBOARD_AUX_Resolution();
                        reg_dx=KEYBOARD_AUX_SampleRate();
                        KEYBOARD_ClrBuffer();
                        reg_ah=0;
                    }
                    else if ((reg_bh==0x01) || (reg_bh==0x02)) { /* set scaling */
                        KEYBOARD_AUX_Write(0xE6u+reg_bh-1u); /* 0xE6 1:1   or 0xE7 2:1 */
                        KEYBOARD_ClrBuffer();
                        CALLBACK_SCF(false); 
                        reg_ah=0;
                    } else {
                        CALLBACK_SCF(true);
                        reg_ah=1;
                    }
                    break;
                case 0x07:      // set callback
                    Mouse_ChangePS2Callback(SegValue(es),reg_bx);
                    CALLBACK_SCF(false);
                    reg_ah=0;
                    break;
                default:
                    LOG_MSG("INT 15h unknown mouse call AX=%04x\n",reg_ax);
                    CALLBACK_SCF(true);
                    reg_ah=1;
                    break;
            }
        }
        else {
            reg_ah=0x86;
            CALLBACK_SCF(true);
            if ((IS_EGAVGA_ARCH) || (machine==MCH_CGA)) {
                /* relict from comparisons, as int15 exits with a retf2 instead of an iret */
                CALLBACK_SZF(false);
            }
        }
        break;
    case 0xc3:      /* set carry flag so BorlandRTM doesn't assume a VECTRA/PS2 */
        reg_ah=0x86;
        CALLBACK_SCF(true);
        break;
    case 0xc4:  /* BIOS POS Programm option Select */
        LOG(LOG_BIOS,LOG_NORMAL)("INT15:Function %X called, bios mouse not supported",reg_ah);
        CALLBACK_SCF(true);
        break;
    case 0x53: // APM BIOS
        if (APMBIOS) {
            LOG(LOG_BIOS,LOG_DEBUG)("APM BIOS call AX=%04x BX=0x%04x CX=0x%04x\n",reg_ax,reg_bx,reg_cx);
            switch(reg_al) {
                case 0x00: // installation check
                    reg_ah = 1;             // major
                    reg_al = APM_BIOS_minor_version;    // minor
                    reg_bx = 0x504d;            // 'PM'
                    reg_cx = (APMBIOS_allow_prot16?0x01:0x00) + (APMBIOS_allow_prot32?0x02:0x00);
                    // 32-bit interface seems to be needed for standby in win95
                    CALLBACK_SCF(false);
                    break;
                case 0x01: // connect real mode interface
                    if(!APMBIOS_allow_realmode) {
                        LOG_MSG("APM BIOS: OS attemped real-mode connection, which is disabled in your dosbox.conf\n");
                        reg_ah = 0x86;  // APM not present
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(reg_bx != 0x0) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(!apm_realmode_connected) { // not yet connected
                        LOG_MSG("APM BIOS: Connected to real-mode interface\n");
                        CALLBACK_SCF(false);
                        APMBIOS_connect_mode = APMBIOS_CONNECT_REAL;
                        apm_realmode_connected=true;
                    } else {
                        LOG_MSG("APM BIOS: OS attempted to connect to real-mode interface when already connected\n");
                        reg_ah = APMBIOS_connected_already_err(); // interface connection already in effect
                        CALLBACK_SCF(true);         
                    }
                    APM_BIOS_connected_minor_version = 0;
                    break;
                case 0x02: // connect 16-bit protected mode interface
                    if(!APMBIOS_allow_prot16) {
                        LOG_MSG("APM BIOS: OS attemped 16-bit protected mode connection, which is disabled in your dosbox.conf\n");
                        reg_ah = 0x06;  // not supported
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(reg_bx != 0x0) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(!apm_realmode_connected) { // not yet connected
                        /* NTS: We use the same callback address for both 16-bit and 32-bit
                         *      because only the DOS callback and RETF instructions are involved,
                         *      which can be executed as either 16-bit or 32-bit code without problems. */
                        LOG_MSG("APM BIOS: Connected to 16-bit protected mode interface\n");
                        CALLBACK_SCF(false);
                        reg_ax = INT15_apm_pmentry >> 16;   // AX = 16-bit code segment (real mode base)
                        reg_bx = INT15_apm_pmentry & 0xFFFF;    // BX = offset of entry point
                        reg_cx = INT15_apm_pmentry >> 16;   // CX = 16-bit data segment (NTS: doesn't really matter)
                        reg_si = 0xFFFF;            // SI = code segment length
                        reg_di = 0xFFFF;            // DI = data segment length
                        APMBIOS_connect_mode = APMBIOS_CONNECT_PROT16;
                        apm_realmode_connected=true;
                    } else {
                        LOG_MSG("APM BIOS: OS attempted to connect to 16-bit protected mode interface when already connected\n");
                        reg_ah = APMBIOS_connected_already_err(); // interface connection already in effect
                        CALLBACK_SCF(true);         
                    }
                    APM_BIOS_connected_minor_version = 0;
                    break;
                case 0x03: // connect 32-bit protected mode interface
                    // Note that Windows 98 will NOT talk to the APM BIOS unless the 32-bit protected mode connection is available.
                    // And if you lie about it in function 0x00 and then fail, Windows 98 will fail with a "Windows protection error".
                    if(!APMBIOS_allow_prot32) {
                        LOG_MSG("APM BIOS: OS attemped 32-bit protected mode connection, which is disabled in your dosbox.conf\n");
                        reg_ah = 0x08;  // not supported
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(reg_bx != 0x0) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(!apm_realmode_connected) { // not yet connected
                        LOG_MSG("APM BIOS: Connected to 32-bit protected mode interface\n");
                        CALLBACK_SCF(false);
                        /* NTS: We use the same callback address for both 16-bit and 32-bit
                         *      because only the DOS callback and RETF instructions are involved,
                         *      which can be executed as either 16-bit or 32-bit code without problems. */
                        reg_ax = INT15_apm_pmentry >> 16;   // AX = 32-bit code segment (real mode base)
                        reg_ebx = INT15_apm_pmentry & 0xFFFF;   // EBX = offset of entry point
                        reg_cx = INT15_apm_pmentry >> 16;   // CX = 16-bit code segment (real mode base)
                        reg_dx = INT15_apm_pmentry >> 16;   // DX = data segment (real mode base) (?? what size?)
                        reg_esi = 0xFFFFFFFF;           // ESI = upper word: 16-bit code segment len  lower word: 32-bit code segment length
                        reg_di = 0xFFFF;            // DI = data segment length
                        APMBIOS_connect_mode = APMBIOS_CONNECT_PROT32;
                        apm_realmode_connected=true;
                    } else {
                        LOG_MSG("APM BIOS: OS attempted to connect to 32-bit protected mode interface when already connected\n");
                        reg_ah = APMBIOS_connected_already_err(); // interface connection already in effect
                        CALLBACK_SCF(true);         
                    }
                    APM_BIOS_connected_minor_version = 0;
                    break;
                case 0x04: // DISCONNECT INTERFACE
                    if(reg_bx != 0x0) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(apm_realmode_connected) {
                        LOG_MSG("APM BIOS: OS disconnected\n");
                        CALLBACK_SCF(false);
                        apm_realmode_connected=false;
                    } else {
                        reg_ah = 0x03;  // interface not connected
                        CALLBACK_SCF(true);         
                    }
                    APM_BIOS_connected_minor_version = 0;
                    break;
                case 0x05: // CPU IDLE
                    if(!apm_realmode_connected) {
                        reg_ah = 0x03;
                        CALLBACK_SCF(true);
                        break;
                    }

                    // Trigger CPU HLT instruction.
                    // NTS: For whatever weird reason, NOT emulating HLT makes Windows 95
                    //      crashy when the APM driver is active! There's something within
                    //      the Win95 kernel that apparently screws up really badly if
                    //      the APM IDLE call returns immediately. The best case scenario
                    //      seems to be that Win95's APM driver has some sort of timing
                    //      logic to it that if it detects an immediate return, immediately
                    //      shuts down and powers off the machine. Windows 98 also seems
                    //      to require a HLT, and will act erratically without it.
                    //
                    //      Also need to note that the choice of "HLT" is not arbitrary
                    //      at all. The APM BIOS standard mentions CPU IDLE either stopping
                    //      the CPU clock temporarily or issuing HLT as a valid method.
                    //
                    // TODO: Make this a dosbox.conf configuration option: what do we do
                    //       on APM idle calls? Allow selection between "nothing" "hlt"
                    //       and "software delay".
                    if (!(reg_flags&0x200)) {
                        LOG(LOG_BIOS,LOG_WARN)("APM BIOS warning: CPU IDLE called with IF=0, not HLTing\n");
                    }
                    else if (cpudecoder == &HLT_Decode) { /* do not re-execute HLT, it makes DOSBox hang */
                        LOG_MSG("APM BIOS warning: CPU IDLE HLT within HLT (DOSBox core failure)\n");
                    }
                    else {
                        CPU_HLT(reg_eip);
                    }
                    break;
                case 0x06: // CPU BUSY
                    if(!apm_realmode_connected) {
                        reg_ah = 0x03;
                        CALLBACK_SCF(true);
                        break;
                    }

                    /* OK. whatever. system no longer idle */
                    CALLBACK_SCF(false);
                    break;
                case 0x07:
                    if(reg_bx != 0x1) {
                        reg_ah = 0x09;  // wrong device ID
                        CALLBACK_SCF(true);         
                        break;
                    }
                    if(!apm_realmode_connected) {
                        reg_ah = 0x03;
                        CALLBACK_SCF(true);
                        break;
                    }
                    switch(reg_cx) {
                        case 0x3: // power off
                            throw(0);
                        default:
                            reg_ah = 0x0A; // invalid parameter value in CX
                            CALLBACK_SCF(true);
                            break;
                    }
                    break;
                case 0x08: // ENABLE/DISABLE POWER MANAGEMENT
                    if(reg_bx != 0x0 && reg_bx != 0x1) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);         
                        break;
                    } else if(!apm_realmode_connected) {
                        reg_ah = 0x03;
                        CALLBACK_SCF(true);
                        break;
                    }
                    if(reg_cx==0x0) LOG_MSG("disable APM for device %4x",reg_bx);
                    else if(reg_cx==0x1) LOG_MSG("enable APM for device %4x",reg_bx);
                    else {
                        reg_ah = 0x0A; // invalid parameter value in CX
                        CALLBACK_SCF(true);
                    }
                    break;
                case 0x0a: // GET POWER STATUS
                    if (!apm_realmode_connected) {
                        reg_ah = 0x03;  // interface not connected
                        CALLBACK_SCF(true);
                        break;
                    }
                    if (reg_bx != 0x0001 && reg_bx != 0x8001) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);         
                        break;
                    }
                    /* FIXME: Allow configuration and shell commands to dictate whether or
                     *        not we emulate a laptop with a battery */
                    reg_bh = 0x01;      // AC line status (1=on-line)
                    reg_bl = 0xFF;      // Battery status (unknown)
                    reg_ch = 0x80;      // Battery flag (no system battery)
                    reg_cl = 0xFF;      // Remaining battery charge (unknown)
                    reg_dx = 0xFFFF;    // Remaining battery life (unknown)
                    reg_si = 0;     // Number of battery units (if called with reg_bx == 0x8001)
                    CALLBACK_SCF(false);
                    break;
                case 0x0b: // GET PM EVENT
                    if (!apm_realmode_connected) {
                        reg_ah = 0x03;  // interface not connected
                        CALLBACK_SCF(true);
                        break;
                    }
                    reg_ah = 0x80; // no power management events pending
                    CALLBACK_SCF(true);
                    break;
                case 0x0d:
                    // NTS: NOT implementing this call can cause Windows 98's APM driver to crash on startup
                    if(reg_bx != 0x0 && reg_bx != 0x1) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);
                        break;
                    } else if(!apm_realmode_connected) {
                        reg_ah = 0x03;
                        CALLBACK_SCF(true);
                        break;
                    }
                    if(reg_cx==0x0) {
                        LOG_MSG("disable APM for device %4x",reg_bx);
                        CALLBACK_SCF(false);
                    }
                    else if(reg_cx==0x1) {
                        LOG_MSG("enable APM for device %4x",reg_bx);
                        CALLBACK_SCF(false);
                    }
                    else {
                        reg_ah = 0x0A; // invalid parameter value in CX
                        CALLBACK_SCF(true);
                    }
                    break;
                case 0x0e:
                    if (APM_BIOS_minor_version != 0) { // APM 1.1 or higher only
                        if(reg_bx != 0x0) {
                            reg_ah = 0x09;  // unrecognized device ID
                            CALLBACK_SCF(true);
                            break;
                        } else if(!apm_realmode_connected) {
                            reg_ah = 0x03;  // interface not connected
                            CALLBACK_SCF(true);
                            break;
                        }
                        reg_ah = reg_ch; /* we are called with desired version in CH,CL, return actual version in AH,AL */
                        reg_al = reg_cl;
                        if(reg_ah != 1) reg_ah = 1;                     // major
                        if(reg_al > APM_BIOS_minor_version) reg_al = APM_BIOS_minor_version;    // minor
                        APM_BIOS_connected_minor_version = reg_al;              // what we decided becomes the interface we emulate
                        LOG_MSG("APM BIOS negotiated to v1.%u",APM_BIOS_connected_minor_version);
                        CALLBACK_SCF(false);
                    }
                    else { // APM 1.0 does not recognize this call
                        reg_ah = 0x0C; // function not supported
                        CALLBACK_SCF(true);
                    }
                    break;
                case 0x0f:
                    if(reg_bx != 0x0 && reg_bx != 0x1) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);         
                        break;
                    } else if(!apm_realmode_connected) {
                        reg_ah = 0x03;
                        CALLBACK_SCF(true);
                        break;
                    }
                    if(reg_cx==0x0) {
                        LOG_MSG("disengage APM for device %4x",reg_bx);
                        CALLBACK_SCF(false);
                    }
                    else if(reg_cx==0x1) {
                        LOG_MSG("engage APM for device %4x",reg_bx);
                        CALLBACK_SCF(false);
                    }
                    else {
                        reg_ah = 0x0A; // invalid parameter value in CX
                        CALLBACK_SCF(true);
                    }
                    break;
                case 0x10:
                    if (!apm_realmode_connected) {
                        reg_ah = 0x03;  // interface not connected
                        CALLBACK_SCF(true);
                        break;
                    }
                    if (reg_bx != 0) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);
                        break;
                    }
                    reg_ah = 0;
                    reg_bl = 0; // number of battery units
                    reg_cx = 0x03; // can enter suspend/standby and will post standby/resume events
                    CALLBACK_SCF(false);
                    break;
                case 0x13://enable/disable/query timer based requests
                    // NTS: NOT implementing this call can cause Windows 98's APM driver to crash on startup
                    if (!apm_realmode_connected) {
                        reg_ah = 0x03;  // interface not connected
                        CALLBACK_SCF(true);
                        break;
                    }
                    if (reg_bx != 0) {
                        reg_ah = 0x09;  // unrecognized device ID
                        CALLBACK_SCF(true);
                        break;
                    }

                    if (reg_cx == 0) { // disable
                        APM_inactivity_timer = false;
                        reg_cx = 0;
                        CALLBACK_SCF(false);
                    }
                    else if (reg_cx == 1) { // enable
                        APM_inactivity_timer = true;
                        reg_cx = 1;
                        CALLBACK_SCF(false);
                    }
                    else if (reg_cx == 2) { // get enabled status
                        reg_cx = APM_inactivity_timer ? 1 : 0;
                        CALLBACK_SCF(false);
                    }
                    else {
                        reg_ah = 0x0A; // invalid parameter value in CX
                        CALLBACK_SCF(true);
                    }
                    break;
                default:
                    LOG_MSG("Unknown APM BIOS call AX=%04x\n",reg_ax);
                    if (!apm_realmode_connected) {
                        reg_ah = 0x03;  // interface not connected
                        CALLBACK_SCF(true);
                        break;
                    }
                    reg_ah = 0x0C; // function not supported
                    CALLBACK_SCF(true);
                    break;
            }
        }
        else {
            reg_ah=0x86;
            CALLBACK_SCF(true);
            LOG_MSG("APM BIOS call attempted. set apmbios=1 if you want power management\n");
            if ((IS_EGAVGA_ARCH) || (machine==MCH_CGA) || (machine==MCH_AMSTRAD)) {
                /* relict from comparisons, as int15 exits with a retf2 instead of an iret */
                CALLBACK_SZF(false);
            }
        }
        break;
    case 0xe8:
        switch (reg_al) {
            case 0x01: { /* E801: memory size */
                    Bitu sz = MEM_TotalPages()*4;
                    if (sz >= 1024) sz -= 1024;
                    else sz = 0;
                    reg_ax = reg_cx = (sz > 0x3C00) ? 0x3C00 : sz; /* extended memory between 1MB and 16MB in KBs */
                    sz -= reg_ax;
                    sz /= 64;   /* extended memory size from 16MB in 64KB blocks */
                    if (sz > 65535) sz = 65535;
                    reg_bx = reg_dx = sz;
                    CALLBACK_SCF(false);
                }
                break;
            case 0x20: { /* E820: MEMORY LISTING */
                    if (reg_edx == 0x534D4150 && reg_ecx >= 20 && (MEM_TotalPages()*4) >= 24000) {
                        /* return a minimalist list:
                         *
                         *    0) 0x000000-0x09EFFF       Free memory
                         *    1) 0x0C0000-0x0FFFFF       Reserved
                         *    2) 0x100000-...            Free memory (no ACPI tables) */
                        if (reg_ebx < 3) {
                            uint32_t base = 0,len = 0,type = 0;
                            Bitu seg = SegValue(es);

                            assert((MEM_TotalPages()*4096) >= 0x100000);

                            switch (reg_ebx) {
                                case 0: base=0x000000; len=0x09F000; type=1; break;
                                case 1: base=0x0C0000; len=0x040000; type=2; break;
                                case 2: base=0x100000; len=(MEM_TotalPages()*4096)-0x100000; type=1; break;
                                default: E_Exit("Despite checks EBX is wrong value"); /* BUG! */
                            }

                            /* write to ES:DI */
                            real_writed(seg,reg_di+0x00,base);
                            real_writed(seg,reg_di+0x04,0);
                            real_writed(seg,reg_di+0x08,len);
                            real_writed(seg,reg_di+0x0C,0);
                            real_writed(seg,reg_di+0x10,type);
                            reg_ecx = 20;

                            /* return EBX pointing to next entry. wrap around, as most BIOSes do.
                             * the program is supposed to stop on CF=1 or when we return EBX == 0 */
                            if (++reg_ebx >= 3) reg_ebx = 0;
                        }
                        else {
                            CALLBACK_SCF(true);
                        }

                        reg_eax = 0x534D4150;
                    }
                    else {
                        reg_eax = 0x8600;
                        CALLBACK_SCF(true);
                    }
                }
                break;
            default:
                LOG(LOG_BIOS,LOG_ERROR)("INT15:Unknown call ah=E8, al=%2X",reg_al);
                reg_ah=0x86;
                CALLBACK_SCF(true);
                if ((IS_EGAVGA_ARCH) || (machine==MCH_CGA) || (machine==MCH_AMSTRAD)) {
                    /* relict from comparisons, as int15 exits with a retf2 instead of an iret */
                    CALLBACK_SZF(false);
                }
        }
        break;
    default:
        LOG(LOG_BIOS,LOG_ERROR)("INT15:Unknown call ax=%4X",reg_ax);
        reg_ah=0x86;
        CALLBACK_SCF(true);
        if ((IS_EGAVGA_ARCH) || (machine==MCH_CGA) || (machine==MCH_AMSTRAD)) {
            /* relict from comparisons, as int15 exits with a retf2 instead of an iret */
            CALLBACK_SZF(false);
        }
    }
    return CBRET_NONE;
}

void BIOS_UnsetupKeyboard(void);
void BIOS_SetupKeyboard(void);
void BIOS_UnsetupDisks(void);
void BIOS_SetupDisks(void);
void CPU_Snap_Back_To_Real_Mode();
void CPU_Snap_Back_Restore();

static Bitu Default_IRQ_Handler(void) {
    IO_WriteB(0x20, 0x0b);
    Bit8u master_isr = IO_ReadB(0x20);
    if (master_isr) {
        IO_WriteB(0xa0, 0x0b);
        Bit8u slave_isr = IO_ReadB(0xa0);
        if (slave_isr) {
            IO_WriteB(0xa1, IO_ReadB(0xa1) | slave_isr);
            IO_WriteB(0xa0, 0x20);
        }
        else IO_WriteB(0x21, IO_ReadB(0x21) | (master_isr & ~4));
        IO_WriteB(0x20, 0x20);
#if C_DEBUG
        Bit16u irq = 0;
        Bit16u isr = master_isr;
        if (slave_isr) isr = slave_isr << 8;
        while (isr >>= 1) irq++;
        LOG(LOG_BIOS, LOG_WARN)("Unexpected IRQ %u", irq);
#endif 
    }
    else master_isr = 0xff;
    mem_writeb(BIOS_LAST_UNEXPECTED_IRQ, master_isr);
    return CBRET_NONE;
}

static Bitu IRQ14_Dummy(void) {
    /* FIXME: That's it? Don't I EOI the PIC? */
    return CBRET_NONE;
}

static Bitu IRQ15_Dummy(void) {
    /* FIXME: That's it? Don't I EOI the PIC? */
    return CBRET_NONE;
}

void On_Software_CPU_Reset();

static Bitu INT18_Handler(void) {
    LOG_MSG("Restart by INT 18h requested\n");
    On_Software_CPU_Reset();
    /* does not return */
    return CBRET_NONE;
}

static Bitu INT19_Handler(void) {
    LOG_MSG("Restart by INT 19h requested\n");
    /* FIXME: INT 19h is sort of a BIOS boot BIOS reset-ish thing, not really a CPU reset at all. */
    On_Software_CPU_Reset();
    /* does not return */
    return CBRET_NONE;
}

void bios_enable_ps2() {
    mem_writew(BIOS_CONFIGURATION,
        mem_readw(BIOS_CONFIGURATION)|0x04); /* PS/2 mouse */
}

void BIOS_ZeroExtendedSize(bool in) {
    if(in) other_memsystems++; 
    else other_memsystems--;
    if(other_memsystems < 0) other_memsystems=0;

    if (IS_PC98_ARCH) {
        Bitu mempages = MEM_TotalPages(); /* in 4KB pages */

        /* What applies to IBM PC/AT (zeroing out the extended memory size)
         * also applies to PC-98, when HIMEM.SYS is loaded */
        if (in) mempages = 0;

        /* extended memory size (286 systems, below 16MB) */
        if (mempages > (1024UL/4UL)) {
            unsigned int ext = ((mempages - (1024UL/4UL)) * 4096UL) / (128UL * 1024UL); /* convert to 128KB units */

            /* extended memory, up to 16MB capacity (for 286 systems?)
             *
             * MS-DOS drivers will "allocate" for themselves by taking from the top of
             * extended memory then subtracting from this value.
             *
             * capacity does not include conventional memory below 1MB, nor any memory
             * above 16MB.
             *
             * PC-98 systems may reserve the top 1MB, limiting the top to 15MB instead.
             *
             * 0x70 = 128KB * 0x70 = 14MB
             * 0x78 = 128KB * 0x70 = 15MB */
            if (ext > 0x78) ext = 0x78;

            mem_writeb(0x401,ext);
        }
        else {
            mem_writeb(0x401,0x00);
        }

        /* extended memory size (386 systems, at or above 16MB) */
        if (mempages > ((1024UL*16UL)/4UL)) {
            unsigned int ext = ((mempages - ((1024UL*16UL)/4UL)) * 4096UL) / (1024UL * 1024UL); /* convert to MB */

            /* extended memory, at or above 16MB capacity (for 386+ systems?)
             *
             * MS-DOS drivers will "allocate" for themselves by taking from the top of
             * extended memory then subtracting from this value.
             *
             * capacity does not include conventional memory below 1MB, nor any memory
             * below 16MB. */
            if (ext > 0xFFFE) ext = 0xFFFE;

            mem_writew(0x594,ext);
        }
        else {
            mem_writew(0x594,0x00);
        }
    }
}

unsigned char do_isapnp_chksum(const unsigned char* d, int i) {
    unsigned char sum = 0;

    while (i-- > 0)
        sum += *d++;

    return (0x100 - sum) & 0xFF;
}

void MEM_ResetPageHandler_Unmapped(Bitu phys_page, Bitu pages);

unsigned int dos_conventional_limit = 0;

bool AdapterROM_Read(Bitu address,unsigned long *size) {
    unsigned char c[3];
    unsigned int i;

    if ((address & 0x1FF) != 0) {
        LOG(LOG_MISC,LOG_DEBUG)("AdapterROM_Read: Caller attempted ROM scan not aligned to 512-byte boundary");
        return false;
    }

    for (i=0;i < 3;i++)
        c[i] = mem_readb(address+i);

    if (c[0] == 0x55 && c[1] == 0xAA) {
        unsigned char chksum=0;
        *size = (unsigned long)c[2] * 512UL;
        for (i=0;i < (unsigned int)(*size);i++) chksum += mem_readb(address+i);
        if (chksum != 0) {
            LOG(LOG_MISC,LOG_WARN)("AdapterROM_Read: Found ROM at 0x%lx but checksum failed\n",(unsigned long)address);
            return false;
        }

        return true;
    }

    return false;
}

#include "src/gui/dosbox.vga16.bmp.h"
#include "src/gui/dosbox.cga640.bmp.h"

void DrawDOSBoxLogoCGA6(unsigned int x,unsigned int y) {
    const unsigned char *s = dosbox_cga640_bmp;
    const unsigned char *sf = s + sizeof(dosbox_cga640_bmp);
    uint32_t width,height;
    unsigned int dx,dy;
    uint32_t off;
    uint32_t sz;

    if (memcmp(s,"BM",2)) return;
    sz = host_readd(s+2); // size of total bitmap
    off = host_readd(s+10); // offset of bitmap
    if ((s+sz) > sf) return;
    if ((s+14+40) > sf) return;

    sz = host_readd(s+34); // biSize
    if ((s+off+sz) > sf) return;
    if (host_readw(s+26) != 1) return; // biBitPlanes
    if (host_readw(s+28) != 1)  return; // biBitCount

    width = host_readd(s+18);
    height = host_readd(s+22);
    if (width > (640-x) || height > (200-y)) return;

    LOG(LOG_MISC,LOG_DEBUG)("Drawing CGA logo (%u x %u)",(int)width,(int)height);
    for (dy=0;dy < height;dy++) {
        uint32_t vram  = ((y+dy) >> 1) * 80;
        vram += ((y+dy) & 1) * 0x2000;
        vram += (x / 8);
        s = dosbox_cga640_bmp + off + ((height-(dy+1))*((width+7)/8));
        for (dx=0;dx < width;dx += 8) {
            mem_writeb(0xB8000+vram,*s);
            vram++;
            s++;
        }
    }
}

/* HACK: Re-use the VGA logo */
void DrawDOSBoxLogoPC98(unsigned int x,unsigned int y) {
    const unsigned char *s = dosbox_vga16_bmp;
    const unsigned char *sf = s + sizeof(dosbox_vga16_bmp);
    unsigned int bit,dx,dy;
    uint32_t width,height;
    unsigned char p[4];
    unsigned char c;
    uint32_t off;
    uint32_t sz;

    if (memcmp(s,"BM",2)) return;
    sz = host_readd(s+2); // size of total bitmap
    off = host_readd(s+10); // offset of bitmap
    if ((s+sz) > sf) return;
    if ((s+14+40) > sf) return;

    sz = host_readd(s+34); // biSize
    if ((s+off+sz) > sf) return;
    if (host_readw(s+26) != 1) return; // biBitPlanes
    if (host_readw(s+28) != 4)  return; // biBitCount

    width = host_readd(s+18);
    height = host_readd(s+22);
    if (width > (640-x) || height > (350-y)) return;

    // EGA/VGA Write Mode 2
    LOG(LOG_MISC,LOG_DEBUG)("Drawing VGA logo as PC-98 (%u x %u)",(int)width,(int)height);
    for (dy=0;dy < height;dy++) {
        uint32_t vram = ((y+dy) * 80) + (x / 8);
        s = dosbox_vga16_bmp + off + ((height-(dy+1))*((width+1)/2));
        for (dx=0;dx < width;dx += 8) {
            p[0] = p[1] = p[2] = p[3] = 0;
            for (bit=0;bit < 8;) {
                c = (*s >> 4);
                p[0] |= ((c >> 0) & 1) << (7 - bit);
                p[1] |= ((c >> 1) & 1) << (7 - bit);
                p[2] |= ((c >> 2) & 1) << (7 - bit);
                p[3] |= ((c >> 3) & 1) << (7 - bit);
                bit++;

                c = (*s++) & 0xF;
                p[0] |= ((c >> 0) & 1) << (7 - bit);
                p[1] |= ((c >> 1) & 1) << (7 - bit);
                p[2] |= ((c >> 2) & 1) << (7 - bit);
                p[3] |= ((c >> 3) & 1) << (7 - bit);
                bit++;
            }

            mem_writeb(0xA8000+vram,p[0]);
            mem_writeb(0xB0000+vram,p[1]);
            mem_writeb(0xB8000+vram,p[2]);
            mem_writeb(0xE0000+vram,p[3]);
            vram++;
        }
    }
}

void DrawDOSBoxLogoVGA(unsigned int x,unsigned int y) {
    const unsigned char *s = dosbox_vga16_bmp;
    const unsigned char *sf = s + sizeof(dosbox_vga16_bmp);
    unsigned int bit,dx,dy;
    uint32_t width,height;
    uint32_t vram;
    uint32_t off;
    uint32_t sz;

    if (memcmp(s,"BM",2)) return;
    sz = host_readd(s+2); // size of total bitmap
    off = host_readd(s+10); // offset of bitmap
    if ((s+sz) > sf) return;
    if ((s+14+40) > sf) return;

    sz = host_readd(s+34); // biSize
    if ((s+off+sz) > sf) return;
    if (host_readw(s+26) != 1) return; // biBitPlanes
    if (host_readw(s+28) != 4)  return; // biBitCount

    width = host_readd(s+18);
    height = host_readd(s+22);
    if (width > (640-x) || height > (350-y)) return;

    // EGA/VGA Write Mode 2
    LOG(LOG_MISC,LOG_DEBUG)("Drawing VGA logo (%u x %u)",(int)width,(int)height);
    IO_Write(0x3CE,0x05); // graphics mode
    IO_Write(0x3CF,0x02); // read=0 write=2 odd/even=0 shift=0 shift256=0
    IO_Write(0x3CE,0x03); // data rotate
    IO_Write(0x3CE,0x00); // no rotate, no XOP
    for (bit=0;bit < 8;bit++) {
        const unsigned char shf = ((bit & 1) ^ 1) * 4;

        IO_Write(0x3CE,0x08); // bit mask
        IO_Write(0x3CF,0x80 >> bit);

        for (dy=0;dy < height;dy++) {
            vram = ((y+dy) * 80) + (x / 8);
            s = dosbox_vga16_bmp + off + (bit/2) + ((height-(dy+1))*((width+1)/2));
            for (dx=bit;dx < width;dx += 8) {
                mem_readb(0xA0000+vram); // load VGA latches
                mem_writeb(0xA0000+vram,(*s >> shf) & 0xF);
                vram++;
                s += 4;
            }
        }
    }
    // restore write mode 0
    IO_Write(0x3CE,0x05); // graphics mode
    IO_Write(0x3CF,0x00); // read=0 write=0 odd/even=0 shift=0 shift256=0
    IO_Write(0x3CE,0x08); // bit mask
    IO_Write(0x3CF,0xFF);
}

static int bios_pc98_posx = 0;

static void BIOS_Int10RightJustifiedPrint(const int x,int &y,const char *msg) {
    const char *s = msg;

    if (machine != MCH_PC98) {
        while (*s != 0) {
            if (*s == '\n') {
                y++;
                reg_eax = 0x0200u;   // set cursor pos
                reg_ebx = 0;        // page zero
                reg_dh = y;     // row 4
                reg_dl = x;     // column 20
                CALLBACK_RunRealInt(0x10);
                s++;
            }
            else {
                reg_eax = 0x0E00u | ((unsigned char)(*s++));
                reg_ebx = 0x07u;
                CALLBACK_RunRealInt(0x10);
            }
        }
    }
    else {
        unsigned int bo;

        while (*s != 0) {
            if (*s == '\n') {
                y++;
                s++;
                bios_pc98_posx = x;

                bo = (((unsigned int)y * 80u) + (unsigned int)bios_pc98_posx) * 2u;
            }
            else if (*s == '\r') {
                s++; /* ignore */
                continue;
            }
            else {
                bo = (((unsigned int)y * 80u) + (unsigned int)(bios_pc98_posx++)) * 2u; /* NTS: note the post increment */

                mem_writew(0xA0000+bo,(unsigned char)(*s++));
                mem_writeb(0xA2000+bo,0xE1);

                bo += 2; /* and keep the cursor following the text */
            }

            reg_eax = 0x1300;   // set cursor pos (PC-98)
            reg_edx = bo;       // byte position
            CALLBACK_RunRealInt(0x18);
        }
    }
}

static Bitu ulimit = 0;
static Bitu t_conv = 0;
static bool bios_first_init=true;
static bool bios_has_exec_vga_bios=false;
static Bitu adapter_scan_start;

/* FIXME: At global scope their destructors are called after the rest of DOSBox has shut down. Move back into BIOS scope. */
static CALLBACK_HandlerObject int4b_callback;
static CALLBACK_HandlerObject callback[20]; /* <- fixme: this is stupid. just declare one per interrupt. */
static CALLBACK_HandlerObject cb_bios_post;
static CALLBACK_HandlerObject callback_pc98_lio;

Bitu call_pnp_r = ~0UL;
Bitu call_pnp_rp = 0;

Bitu call_pnp_p = ~0UL;
Bitu call_pnp_pp = 0;

Bitu isapnp_biosstruct_base = 0;

Bitu BIOS_boot_code_offset = 0;
Bitu BIOS_bootfail_code_offset = 0;

bool bios_user_reset_vector_blob_run = false;
Bitu bios_user_reset_vector_blob = 0;

Bitu bios_user_boot_hook = 0;

void CALLBACK_DeAllocate(Bitu in);

void BIOS_OnResetComplete(Section *x);

Bitu call_irq0 = 0;
Bitu call_irq07default = 0;
Bitu call_irq815default = 0;

void write_FFFF_PC98_signature() {
    /* this may overwrite the existing signature.
     * PC-98 systems DO NOT have an ASCII date at F000:FFF5
     * and the WORD value at F000:FFFE is said to be a checksum of the BIOS */

    // The farjump at the processor reset entry point (jumps to POST routine)
    phys_writeb(0xffff0,0xEA);                  // FARJMP
    phys_writew(0xffff1,RealOff(BIOS_DEFAULT_RESET_LOCATION));  // offset
    phys_writew(0xffff3,RealSeg(BIOS_DEFAULT_RESET_LOCATION));  // segment

    // write nothing (not used)
    for(Bitu i = 0; i < 9; i++) phys_writeb(0xffff5+i,0);

    // fake BIOS checksum
    phys_writew(0xffffe,0xABCD);
}

void gdc_egc_enable_update_vars(void) {
    unsigned char b;

    b = mem_readb(0x54D);
    b &= ~0x40;
    if (enable_pc98_egc) b |= 0x40;
    mem_writeb(0x54D,b);

    b = mem_readb(0x597);
    b &= ~0x04;
    if (enable_pc98_egc) b |= 0x04;
    mem_writeb(0x597,b);

    if (!enable_pc98_egc)
        pc98_gdc_vramop &= ~(1 << VOPBIT_EGC);
}

void gdc_grcg_enable_update_vars(void) {
    unsigned char b;

    b = mem_readb(0x54C);
    b &= ~0x02;
    if (enable_pc98_grcg) b |= 0x02;
    mem_writeb(0x54C,b);
    
    //TODO: How to reset GRCG?
}


void gdc_16color_enable_update_vars(void) {
    unsigned char b;

    b = mem_readb(0x54C);
    b &= ~0x04;
    if (enable_pc98_16color) b |= 0x04;
    mem_writeb(0x54C,b);

    if(!enable_pc98_256color) {//force switch to 16-colors mode
        void pc98_port6A_command_write(unsigned char b);
        pc98_port6A_command_write(0x20);
    }
    if(!enable_pc98_16color) {//force switch to 8-colors mode
        void pc98_port6A_command_write(unsigned char b);
        pc98_port6A_command_write(0x00);
    }
}

Bit32u BIOS_get_PC98_INT_STUB(void) {
    return callback[18].Get_RealPointer();
}

/* NTS: Remember the 8259 is non-sentient, and the term "slave" is used in a computer programming context */
static Bitu Default_IRQ_Handler_Cooperative_Slave_Pic(void) {
    /* PC-98 style IRQ 8-15 handling.
     *
     * This mimics the recommended procedure [https://www.webtech.co.jp/company/doc/undocumented_mem/io_pic.txt]
     *
     *  mov al,20h      ;Send EOI to SLAVE
     *  out 0008h,al
     *  jmp $+2         ;I/O WAIT
     *  mov al,0Bh      ;ISR read mode set(slave)
     *  out 0008h,al
     *  jmp $+2         ;I/O WAIT
     *  in  al,0008h    ;ISR read(slave)
     *  cmp al,00h      ;slave pic in-service ?
     *  jne EoiEnd
     *  mov al,20h      ;Send EOI to MASTER
     *  out 0000h,al
     */
    IO_WriteB(IS_PC98_ARCH ? 0x08 : 0xA0,0x20); // send EOI to slave
    IO_WriteB(IS_PC98_ARCH ? 0x08 : 0xA0,0x0B); // ISR read mode set
    if (IO_ReadB(IS_PC98_ARCH ? 0x08 : 0xA0) == 0) // if slave pic in service..
        IO_WriteB(IS_PC98_ARCH ? 0x00 : 0x20,0x20); // then EOI the master

    return CBRET_NONE;
}

static int bios_post_counter = 0;

class BIOS:public Module_base{
private:
    static Bitu cb_bios_post__func(void) {
        void TIMER_BIOS_INIT_Configure();
#if C_DEBUG
        void DEBUG_CheckCSIP();

# if C_HEAVY_DEBUG
        /* the game/app obviously crashed, which is way more important
         * to log than what we do here in the BIOS at POST */
        void DEBUG_StopLog(void);
        DEBUG_StopLog();
# endif
#endif

        {
            Section_prop * section=static_cast<Section_prop *>(control->GetSection("dosbox"));
            int val = section->Get_int("reboot delay");

            if (val < 0)
                val = IS_PC98_ARCH ? 1000 : 500;

            reset_post_delay = (unsigned int)val;
        }

        if (bios_post_counter != 0 && reset_post_delay != 0) {
            /* reboot delay, in case the guest OS/application had something to day before hitting the "reset" signal */
            Bit32u lasttick=GetTicks();
            while ((GetTicks()-lasttick) < reset_post_delay) {
                void CALLBACK_IdleNoInts(void);
                CALLBACK_IdleNoInts();
            }
        }

        if (bios_post_counter != 0) {
            /* turn off the PC speaker if the guest left it on at reset */
            if (IS_PC98_ARCH) {
                IO_Write(0x37,0x07);
            }
            else {
                IO_Write(0x61,IO_Read(0x61) & (~3u));
            }
        }

        bios_post_counter++;

        if (bios_first_init) {
            /* clear the first 1KB-32KB */
            for (Bit16u i=0x400;i<0x8000;i++) real_writeb(0x0,i,0);
        }

        if (IS_PC98_ARCH) {
            for (unsigned int i=0;i < 20;i++) callback[i].Uninstall();

            /* clear out 0x50 segment (TODO: 0x40 too?) */
            for (unsigned int i=0;i < 0x100;i++) phys_writeb(0x500+i,0);

            write_FFFF_PC98_signature();
            BIOS_ZeroExtendedSize(false);

            unsigned char memsize_real_code = 0;
            Bitu mempages = MEM_TotalPages(); /* in 4KB pages */

            /* NTS: Fill in the 3-bit code in FLAGS1 that represents
             *      how much lower conventional memory is in the system.
             *
             *      Note that MEM.EXE requires this value, or else it
             *      will complain about broken UMB linkage and fail
             *      to show anything else. */
            /* TODO: In the event we eventually support "high resolution mode"
             *       we can indicate 768KB here, code == 5, meaning that
             *       the RAM extends up to 0xBFFFF instead of 0x9FFFF */
            if (mempages >= (640UL/4UL))        /* 640KB */
                memsize_real_code = 4;
            else if (mempages >= (512UL/4UL))   /* 512KB */
                memsize_real_code = 3;
            else if (mempages >= (384UL/4UL))   /* 384KB */
                memsize_real_code = 2;
            else if (mempages >= (256UL/4UL))   /* 256KB */
                memsize_real_code = 1;
            else                                /* 128KB */
                memsize_real_code = 0;

            void pc98_msw3_set_ramsize(const unsigned char b);
            pc98_msw3_set_ramsize(memsize_real_code);

            /* CRT status */
            /* bit[7:6] = 00=conventional compatible  01=extended attr JEH  10=extended attr EGH
             * bit[5:5] = Single event timer in use flag    1=busy  0=not used
             * bit[4:4] = ?
             * bit[3:3] = raster scan    1=non-interlaced     0=interlaced
             * bit[2:2] = Content ruled line color  1=I/O set value    0=attributes of VRAM
             * bit[1:1] = ?
             * bit[0:0] = 480-line mode    1=640x480     0=640x400 or 640x200 */
            mem_writeb(0x459,0x08/*non-interlaced*/);

            /* CPU/Display */
            /* bit[7:7] = 486SX equivalent (?)                                                                      1=yes
             * bit[6:6] = PC-9821 Extended Graph Architecture supported (FIXME: Is this the same as having EGC?)    1=yes
             * bit[5:5] = LCD display is color                                                                      1=yes 0=no
             * bit[4:4] = ?
             * bit[3:3] = ROM drive allow writing
             * bit[2:2] = 98 NOTE PC-9801N-08 expansion I/O box connected
             * bit[1:1] = 98 NOTE prohibit transition to power saving mode
             * bit[0:0] = 98 NOTE coprocessor function available */
            mem_writeb(0x45C,(enable_pc98_egc ? 0x40/*Extended Graphics*/ : 0x00));

            /* Keyboard type */
            /* bit[7:7] = ?
             * bit[6:6] = keyboard type bit 1
             * bit[5:5] = EMS page frame at B0000h 1=present 0=none
             * bit[4:4] = EMS page frame at B0000h 1=page frame 0=G-VRAM
             * bit[3:3] = keyboard type bit 0
             * bit[2:2] = High resolution memory window available
             * bit[1:1] = ?
             * bit[0:0] = ?
             *
             * keyboard bits[1:0] from bit 6 as bit 1 and bit 3 as bit 0 combined:
             * 11 = new keyboard (NUM key, DIP switch 2-7 OFF)
             * 10 = new keyboard (without NUM key)
             * 01 = new keyboard (NUM key, DIP switch 2-7 ON)
             * 00 = old keyboard
             *
             * The old keyboard is documented not to support software control of CAPS and KANA states */
            /* TODO: Make this a dosbox.conf option. Default is new keyboard without NUM key because that is what
             *       keyboard emulation currently acts like anyway. */
            mem_writeb(0x481,0x40/*bit 6=1 bit 3=0 new keyboard without NUM key*/);

            /* BIOS flags */
            /* bit[7:7] = Startup            1=hot start    0=cold start
             * bit[6:6] = BASIC type         ??
             * bit[5:5] = Keyboard beep      1=don't beep   0=beep          ... when buffer full
             * bit[4:4] = Expansion conv RAM 1=present      0=absent
             * bit[3:3] = ??
             * bit[2:2] = ??
             * bit[1:1] = HD mode            1=1MB mode     0=640KB mode    ... of the floppy drive
             * bit[0:0] = Model              1=other        0=PC-9801 original */
            /* NTS: MS-DOS 5.0 appears to reduce it's BIOS calls and render the whole
             *      console as green IF bit 0 is clear.
             *
             *      If bit 0 is set, INT 1Ah will be hooked by MS-DOS and, for some odd reason,
             *      MS-DOS's hook proc will call to our INT 1Ah + 0x19 bytes. */
            mem_writeb(0x500,0x01 | 0x02/*high density drive*/);

            /* BIOS flags */
            /* timer setup will set/clear bit 7 */
            /* bit[7:7] = system clock freq  1=8MHz         0=5/10Mhz
             *          = timer clock freq   1=1.9968MHz    0=2.4576MHz
             * bit[6:6] = CPU                1=V30          0=Intel (8086 through Pentium)
             * bit[5:5] = Model info         1=Other model  0=PC-9801 Muji, PC-98XA
             * bit[4:4] = Model info         ...
             * bit[3:3] = Model info         1=High res     0=normal
             * bit[2:0] = Realmode memsize
             *                             000=128KB      001=256KB
             *                             010=384KB      011=512KB
             *                             100=640KB      101=768KB
             *
             * Ref: http://hackipedia.org/browse/Computer/Platform/PC,%20NEC%20PC-98/Collections/Undocumented%209801,%209821%20Volume%202%20(webtech.co.jp)/memsys.txt */
            /* NTS: High resolution means 640x400, not the 1120x750 mode known as super high resolution mode.
             *      DOSBox-X does not yet emulate super high resolution nor does it emulate the 15khz 200-line "standard" mode.
             *      ref: https://github.com/joncampbell123/dosbox-x/issues/906#issuecomment-434513930
             *      ref: https://jisho.org/search?utf8=%E2%9C%93&keyword=%E8%B6%85 */
            mem_writeb(0x501,0x20 | memsize_real_code);

            /* keyboard buffer */
            mem_writew(0x524/*tail*/,0x502);
            mem_writew(0x526/*tail*/,0x502);

            /* number of scanlines per text row - 1 */
            mem_writeb(0x53B,0x0F); // CRT_RASTER, 640x400 24.83KHz-hsync 56.42Hz-vsync

            /* Text screen status.
             * Note that most of the bits are used verbatim in INT 18h AH=0Ah/AH=0Bh */
            /* bit[7:7] = High resolution display                   1=yes           0=no (standard)         NOT super high res
             * bit[6:6] = vsync                                     1=VSYNC wait    0=end of vsync handling
             * bit[5:5] = unused
             * bit[4:4] = Number of lines                           1=30 lines      0=20/25 lines
             * bit[3:3] = K-CG access mode                          1=dot access    0=code access
             * bit[2:2] = Attribute mode (how to handle bit 4)      1=Simp. graphic 0=Vertical line
             * bit[1:1] = Number of columns                         1=40 cols       0=80 cols
             * bit[0:0] = Number of lines                           1=20/30 lines   0=25 lines */
            mem_writeb(0x53C,(true/*TODO*/ ? 0x80/*high res*/ : 0x00/*standard*/));

            /* BIOS raster location */
            mem_writew(0x54A,0x1900);

            /* BIOS flags */
            /* bit[7:7] = Graphics display state                    1=Visible       0=Blanked (hidden)
             * bit[6:6] = CRT type                                  1=high res      0=standard              NOT super high res
             * bit[5:5] = Horizontal sync rate                      1=31.47KHz      0=24.83KHz
             * bit[4:4] = CRT line mode                             1=480-line      0=400-line
             * bit[3:3] = Number of user-defined characters         1=188+          0=63
             * bit[2:2] = Extended graphics RAM (for 16-color)      1=present       0=absent
             * bit[1:1] = Graphics Charger is present               1=present       0=absent
             * bit[0:0] = DIP switch 1-8 at startup                 1=ON            0=OFF (?) */
            mem_writeb(0x54C,(true/*TODO*/ ? 0x40/*high res*/ : 0x00/*standard*/) | (enable_pc98_grcg ? 0x02 : 0x00) | (enable_pc98_16color ? 0x04 : 0x00) | (pc98_31khz_mode ? 0x20/*31khz*/ : 0x00/*24khz*/) | (enable_pc98_188usermod ? 0x08 : 0x00)); // PRXCRT, 16-color G-VRAM, GRCG

            /* BIOS flags */
            /* bit[7:7] = 256-color board present (PC-H98)
             * bit[6:6] = Enhanced Graphics Charger (EGC) is present
             * bit[5:5] = GDC at 5.0MHz at boot up (copy of DIP switch 2-8 at startup)      1=yes 0=no
             * bit[4:4] = Always "flickerless" drawing mode
             * bit[3:3] = Drawing mode with flicker
             * bit[2:2] = GDC clock                                                         1=5MHz 0=2.5MHz
             * bit[1:0] = Drawing mode of the GDC
             *              00 = REPLACE
             *              01 = COMPLEMENT
             *              10 = CLEAR
             *              11 = SET */
            mem_writeb(0x54D,
                    (enable_pc98_256color ? 0x80 : 0x00) |
                    (enable_pc98_egc ? 0x40 : 0x00) |
                    (gdc_5mhz_mode ? 0x20 : 0x00) |
                    (gdc_5mhz_mode ? 0x04 : 0x00)); // EGC

            /* BIOS flags */
            /* bit[7:7] = INT 18h AH=30h/31h support enabled
             * bit[6:3] = 0 (unused)
             * bit[2:2] = Enhanced Graphics Mode (EGC) supported
             * bit[1:0] = Graphic resolution
             *             00 = 640x200 upper half  (2/8/16-color mode)
             *             01 = 640x200 lower half  (2/8/16-color mode)
             *             10 = 640x400             (2/8/16/256-color mode)
             *             11 = 640x480             256-color mode */
            mem_writeb(0x597,(enable_pc98_egc ? 0x04 : 0x00)/*EGC*/ |
                             (enable_pc98_egc ? 0x80 : 0x00)/*supports INT 18h AH=30h and AH=31h*/ |
                             2/*640x400*/);
            /* TODO: I would like to eventually add a dosbox.conf option that controls whether INT 18h AH=30h and 31h
             *       are enabled, so that retro-development can test code to see how it acts on a newer PC-9821
             *       that supports it vs an older PC-9821 that doesn't.
             *
             *       If the user doesn't set the option, then it is "auto" and determined by machine= PC-98 model and
             *       by another option in dosbox.conf that determines whether 31khz support is enabled.
             *
             *       NOTED: Neko Project II determines INT 18h AH=30h availability by whether or not it was compiled
             *              with 31khz hsync support (SUPPORT_CRT31KHZ) */
        }

        if (bios_user_reset_vector_blob != 0 && !bios_user_reset_vector_blob_run) {
            LOG_MSG("BIOS POST: Running user reset vector blob at 0x%lx",(unsigned long)bios_user_reset_vector_blob);
            bios_user_reset_vector_blob_run = true;

            assert((bios_user_reset_vector_blob&0xF) == 0); /* must be page aligned */

            SegSet16(cs,bios_user_reset_vector_blob>>4);
            reg_eip = 0;

#if C_DEBUG
            /* help the debugger reflect the new instruction pointer */
            DEBUG_CheckCSIP();
#endif

            return CBRET_NONE;
        }

        if (cpu.pmode) E_Exit("BIOS error: POST function called while in protected/vm86 mode");

        CPU_CLI();

        /* we need A20 enabled for BIOS boot-up */
        void A20Gate_OverrideOn(Section *sec);
        void MEM_A20_Enable(bool enabled);
        A20Gate_OverrideOn(NULL);
        MEM_A20_Enable(true);

        BIOS_OnResetComplete(NULL);

        adapter_scan_start = 0xC0000;
        bios_has_exec_vga_bios = false;
        LOG(LOG_MISC,LOG_DEBUG)("BIOS: executing POST routine");

        // TODO: Anything we can test in the CPU here?

        // initialize registers
        SegSet16(ds,0x0000);
        SegSet16(es,0x0000);
        SegSet16(fs,0x0000);
        SegSet16(gs,0x0000);
        SegSet16(ss,0x0000);

        {
            Bitu sz = MEM_TotalPages();

            /* The standard BIOS is said to put it's stack (at least at OS boot time) 512 bytes past the end of the boot sector
             * meaning that the boot sector loads to 0000:7C00 and the stack is set grow downward from 0000:8000 */

            if (sz > 8) sz = 8; /* 4KB * 8 = 32KB = 0x8000 */
            sz *= 4096;
            reg_esp = sz - 4;
            reg_ebp = 0;
            LOG(LOG_MISC,LOG_DEBUG)("BIOS: POST stack set to 0000:%04x",reg_esp);
        }

        if (dosbox_int_iocallout != IO_Callout_t_none) {
            IO_FreeCallout(dosbox_int_iocallout);
            dosbox_int_iocallout = IO_Callout_t_none;
        }

        if (isapnp_biosstruct_base != 0) {
            ROMBIOS_FreeMemory(isapnp_biosstruct_base);
            isapnp_biosstruct_base = 0;
        }

        if (BOCHS_PORT_E9) {
            delete BOCHS_PORT_E9;
            BOCHS_PORT_E9=NULL;
        }
        if (ISAPNP_PNP_ADDRESS_PORT) {
            delete ISAPNP_PNP_ADDRESS_PORT;
            ISAPNP_PNP_ADDRESS_PORT=NULL;
        }
        if (ISAPNP_PNP_DATA_PORT) {
            delete ISAPNP_PNP_DATA_PORT;
            ISAPNP_PNP_DATA_PORT=NULL;
        }
        if (ISAPNP_PNP_READ_PORT) {
            delete ISAPNP_PNP_READ_PORT;
            ISAPNP_PNP_READ_PORT=NULL;
        }

        extern Bitu call_default;

        if (IS_PC98_ARCH) {
            /* INT 00h-FFh generic stub routine */
            /* NTS: MS-DOS on PC-98 will fill all yet-unused interrupt vectors with a stub.
             *      No vector is left at 0000:0000. On a related note, PC-98 games apparently
             *      like to call INT 33h (mouse functions) without first checking that the
             *      vector is non-null. */
            callback[18].Uninstall();
            callback[18].Install(&INTGEN_PC98_Handler,CB_IRET,"Int stub ???");
            for (unsigned int i=0x00;i < 0x100;i++) RealSetVec(i,callback[18].Get_RealPointer());

            for (unsigned int i=0x00;i < 0x08;i++)
                real_writed(0,i*4,CALLBACK_RealPointer(call_default));
        }
        else {
            /* Clear the vector table */
            for (Bit16u i=0x70*4;i<0x400;i++) real_writeb(0x00,i,0);

            /* Only setup default handler for first part of interrupt table */
            for (Bit16u ct=0;ct<0x60;ct++) {
                real_writed(0,ct*4,CALLBACK_RealPointer(call_default));
            }
            for (Bit16u ct=0x68;ct<0x70;ct++) {
                real_writed(0,ct*4,CALLBACK_RealPointer(call_default));
            }

            // default handler for IRQ 2-7
            for (Bit16u ct=0x0A;ct <= 0x0F;ct++)
                RealSetVec(ct,BIOS_DEFAULT_IRQ07_DEF_LOCATION);
        }

        if (unhandled_irq_method == UNHANDLED_IRQ_COOPERATIVE_2ND) {
            // PC-98 style: Master PIC ack with 0x20 for IRQ 0-7.
            //              For the slave PIC, ack with 0x20 on the slave, then only ack the master (cascade interrupt)
            //              if the ISR register on the slave indicates none are in service.
            CALLBACK_Setup(call_irq07default,NULL,CB_IRET_EOI_PIC1,Real2Phys(BIOS_DEFAULT_IRQ07_DEF_LOCATION),"bios irq 0-7 default handler");
            CALLBACK_Setup(call_irq815default,Default_IRQ_Handler_Cooperative_Slave_Pic,CB_IRET,Real2Phys(BIOS_DEFAULT_IRQ815_DEF_LOCATION),"bios irq 8-15 default handler");
        }
        else {
            // IBM PC style: Master PIC ack with 0x20, slave PIC ack with 0x20, no checking
            CALLBACK_Setup(call_irq07default,NULL,CB_IRET_EOI_PIC1,Real2Phys(BIOS_DEFAULT_IRQ07_DEF_LOCATION),"bios irq 0-7 default handler");
            CALLBACK_Setup(call_irq815default,NULL,CB_IRET_EOI_PIC2,Real2Phys(BIOS_DEFAULT_IRQ815_DEF_LOCATION),"bios irq 8-15 default handler");
        }

        if (IS_PC98_ARCH) {
            BIOS_UnsetupKeyboard();
            BIOS_UnsetupDisks();

            /* no such INT 4Bh */
            int4b_callback.Uninstall();

            /* remove some IBM-style BIOS interrupts that don't exist on PC-98 */
            /* IRQ to INT arrangement
             *
             * IBM          PC-98           IRQ
             * --------------------------------
             * 0x08         0x08            0
             * 0x09         0x09            1
             * 0x0A CASCADE 0x0A            2
             * 0x0B         0x0B            3
             * 0x0C         0x0C            4
             * 0x0D         0x0D            5
             * 0x0E         0x0E            6
             * 0x0F         0x0F CASCADE    7
             * 0x70         0x10            8
             * 0x71         0x11            9
             * 0x72         0x12            10
             * 0x73         0x13            11
             * 0x74         0x14            12
             * 0x75         0x15            13
             * 0x76         0x16            14
             * 0x77         0x17            15
             *
             * As part of the change the IRQ cascade emulation needs to change for PC-98 as well.
             * IBM uses IRQ 2 for cascade.
             * PC-98 uses IRQ 7 for cascade. */

            void INT10_EnterPC98(Section *sec);
            INT10_EnterPC98(NULL); /* INT 10h */

            callback_pc98_lio.Uninstall();

            callback[1].Uninstall(); /* INT 11h */
            callback[2].Uninstall(); /* INT 12h */
            callback[3].Uninstall(); /* INT 14h */
            callback[4].Uninstall(); /* INT 15h */
            callback[5].Uninstall(); /* INT 17h */
            callback[6].Uninstall(); /* INT 1Ah */
            callback[7].Uninstall(); /* INT 1Ch */
            callback[10].Uninstall(); /* INT 19h */
            callback[11].Uninstall(); /* INT 76h: IDE IRQ 14 */
            callback[12].Uninstall(); /* INT 77h: IDE IRQ 15 */
            callback[15].Uninstall(); /* INT 18h: Enter BASIC */

            /* IRQ 6 is nothing special */
            callback[13].Uninstall(); /* INT 0Eh: IDE IRQ 6 */
            callback[13].Install(NULL,CB_IRET_EOI_PIC1,"irq 6");

            /* IRQ 8 is nothing special */
            callback[8].Uninstall();
            callback[8].Install(NULL,CB_IRET_EOI_PIC2,"irq 8");

            /* IRQ 9 is nothing special */
            callback[9].Uninstall();
            callback[9].Install(NULL,CB_IRET_EOI_PIC2,"irq 9");

            /* INT 18h keyboard and video display functions */
            callback[1].Install(&INT18_PC98_Handler,CB_INT16,"Int 18 keyboard and display");
            callback[1].Set_RealVec(0x18,/*reinstall*/true);

            /* INT 19h *STUB* */
            callback[2].Install(&INT19_PC98_Handler,CB_IRET,"Int 19 ???");
            callback[2].Set_RealVec(0x19,/*reinstall*/true);

            /* INT 1Ah *STUB* */
            callback[3].Install(&INT1A_PC98_Handler,CB_IRET,"Int 1A ???");
            callback[3].Set_RealVec(0x1A,/*reinstall*/true);

            /* MS-DOS 5.0 FIXUP:
             * - For whatever reason, if we set bits in the BIOS data area that
             *   indicate we're NOT the original model of the PC-98, MS-DOS will
             *   hook our INT 1Ah and then call down to 0x19 bytes into our
             *   INT 1Ah procedure. If anyone can explain this, I'd like to hear it. --J.C.
             *
             * NTS: On real hardware, the BIOS appears to have an INT 1Ah, a bunch of NOPs,
             *      then at 0x19 bytes into the procedure, the actual handler. This is what
             *      MS-DOS is pointing at.
             *
             *      But wait, there's more.
             *
             *      MS-DOS calldown pushes DS and DX onto the stack (after the IRET frame)
             *      before JMPing into the BIOS.
             *
             *      Apparently the function at INT 1Ah + 0x19 is expected to do this:
             *
             *      <function code>
             *      POP     DX
             *      POP     DS
             *      IRET
             *
             *      I can only imaging what a headache this might have caused NEC when
             *      maintaining the platform and compatibility! */
            {
                Bitu addr = callback[3].Get_RealPointer();
                addr = ((addr >> 16) << 4) + (addr & 0xFFFF);

                /* to make this work, we need to pop the two regs, then JMP to our
                 * callback and proceed as normal. */
                phys_writeb(addr + 0x19,0x5A);       // POP DX
                phys_writeb(addr + 0x1A,0x1F);       // POP DS
                phys_writeb(addr + 0x1B,0xEB);       // jmp short ...
                phys_writeb(addr + 0x1C,0x100 - 0x1D);
            }

            /* INT 1Bh *STUB* */
            callback[4].Install(&INT1B_PC98_Handler,CB_IRET,"Int 1B ???");
            callback[4].Set_RealVec(0x1B,/*reinstall*/true);

            /* INT 1Ch *STUB* */
            callback[5].Install(&INT1C_PC98_Handler,CB_IRET,"Int 1C ???");
            callback[5].Set_RealVec(0x1C,/*reinstall*/true);

            /* INT 1Dh *STUB* */
            /* Place it in the PC-98 int vector area at FD80:0000 to satisfy some DOS games
             * that detect PC-98 from the segment value of the vector (issue #927).
             * Note that on real hardware (PC-9821) INT 1Dh appears to be a stub that IRETs immediately. */
            callback[6].Install(&INT1D_PC98_Handler,CB_IRET,"Int 1D ???");
//            callback[6].Set_RealVec(0x1D,/*reinstall*/true);
            {
                Bitu ofs = 0xFD813; /* 0xFD80:0013 try not to look like a phony address */
                unsigned int vec = 0x1D;
                Bit32u target = callback[6].Get_RealPointer();

                phys_writeb(ofs+0,0xEA);        // JMP FAR <callback>
                phys_writed(ofs+1,target);

                phys_writew((vec*4)+0,(ofs-0xFD800));
                phys_writew((vec*4)+2,0xFD80);
            }

            /* INT 1Eh *STUB* */
            callback[7].Install(&INT1E_PC98_Handler,CB_IRET,"Int 1E ???");
            callback[7].Set_RealVec(0x1E,/*reinstall*/true);

            /* INT 1Fh *STUB* */
            callback[10].Install(&INT1F_PC98_Handler,CB_IRET,"Int 1F ???");
            callback[10].Set_RealVec(0x1F,/*reinstall*/true);

            /* INT DCh *STUB* */
            callback[16].Install(&INTDC_PC98_Handler,CB_IRET,"Int DC ???");
            callback[16].Set_RealVec(0xDC,/*reinstall*/true);

            /* INT F2h *STUB* */
            callback[17].Install(&INTF2_PC98_Handler,CB_IRET,"Int F2 ???");
            callback[17].Set_RealVec(0xF2,/*reinstall*/true);

            // default handler for IRQ 2-7
            for (Bit16u ct=0x0A;ct <= 0x0F;ct++)
                RealSetVec(ct,BIOS_DEFAULT_IRQ07_DEF_LOCATION);

            // default handler for IRQ 8-15
            for (Bit16u ct=0;ct < 8;ct++)
                RealSetVec(ct+(IS_PC98_ARCH ? 0x10 : 0x70),BIOS_DEFAULT_IRQ815_DEF_LOCATION);

            // LIO graphics interface (number of entry points, unknown WORD value and offset into the segment).
            // For more information see Chapter 6 of this PDF [https://ia801305.us.archive.org/8/items/PC9800TechnicalDataBookBIOS1992/PC-9800TechnicalDataBook_BIOS_1992_text.pdf]
            {
                callback_pc98_lio.Install(&PC98_BIOS_LIO,CB_IRET,"LIO graphics library");

                Bitu ofs = 0xF990u << 4u; // F990:0000...
                unsigned int entrypoints = 0x11;
                Bitu final_addr = callback_pc98_lio.Get_RealPointer();

                /* NTS: Based on GAME/MAZE 999 behavior, these numbers are interrupt vector numbers.
                 *      The entry point marked 0xA0 is copied by the game to interrupt vector A0 and
                 *      then called with INT A0h even though it blindly assumes the numbers are
                 *      sequential from 0xA0-0xAF. */
                unsigned char entrypoint_indexes[0x11] = {
                    0xA0,   0xA1,   0xA2,   0xA3,       // +0x00
                    0xA4,   0xA5,   0xA6,   0xA7,       // +0x04
                    0xA8,   0xA9,   0xAA,   0xAB,       // +0x08
                    0xAC,   0xAD,   0xAE,   0xAF,       // +0x0C
                    0xCE                                // +0x10
                };

                assert(((entrypoints * 4) + 4) <= 0x50);
                assert((50 + (entrypoints * 7)) <= 0x100); // a 256-byte region is set aside for this!

                phys_writed(ofs+0,entrypoints);
                for (unsigned int ent=0;ent < entrypoints;ent++) {
                    /* each entry point is "MOV AL,<entrypoint> ; JMP FAR <callback>" */
                    /* Yksoft1's patch suggests a segment offset of 0x50 which I'm OK with */
                    unsigned int ins_ofs = ofs + 0x50 + (ent * 7);

                    phys_writew(ofs+4+(ent*4)+0,entrypoint_indexes[ent]);
                    phys_writew(ofs+4+(ent*4)+2,ins_ofs - ofs);

                    phys_writeb(ins_ofs+0,0xB0);                        // MOV AL,(entrypoint index)
                    phys_writeb(ins_ofs+1,entrypoint_indexes[ent]);
                    phys_writeb(ins_ofs+2,0xEA);                        // JMP FAR <callback>
                    phys_writed(ins_ofs+3,final_addr);
                    // total:   ins_ofs+7
                }
            }
        }

        if (IS_PC98_ARCH) {
            real_writew(0,0x58A,0x0000U); // countdown timer value
            PIC_SetIRQMask(0,true); /* PC-98 keeps the timer off unless INT 1Ch is called to set a timer interval */
        }

        bool null_68h = false;

        {
            Section_prop * section=static_cast<Section_prop *>(control->GetSection("dos"));

            null_68h = section->Get_bool("zero unused int 68h");
        }

        /* Default IRQ handler */
        if (call_irq_default == 0)
            call_irq_default = CALLBACK_Allocate();
        CALLBACK_Setup(call_irq_default, &Default_IRQ_Handler, CB_IRET, "irq default");
        RealSetVec(0x0b, CALLBACK_RealPointer(call_irq_default)); // IRQ 3
        RealSetVec(0x0c, CALLBACK_RealPointer(call_irq_default)); // IRQ 4
        RealSetVec(0x0d, CALLBACK_RealPointer(call_irq_default)); // IRQ 5
        RealSetVec(0x0f, CALLBACK_RealPointer(call_irq_default)); // IRQ 7
        if (!IS_PC98_ARCH) {
            RealSetVec(0x72, CALLBACK_RealPointer(call_irq_default)); // IRQ 10
            RealSetVec(0x73, CALLBACK_RealPointer(call_irq_default)); // IRQ 11
        }

        // setup a few interrupt handlers that point to bios IRETs by default
        real_writed(0,0x66*4,CALLBACK_RealPointer(call_default));   //war2d
        real_writed(0,0x67*4,CALLBACK_RealPointer(call_default));
        if (machine==MCH_CGA || null_68h) real_writed(0,0x68*4,0);  //Popcorn
        real_writed(0,0x5c*4,CALLBACK_RealPointer(call_default));   //Network stuff
        //real_writed(0,0xf*4,0); some games don't like it

        bios_first_init = false;

        DispatchVMEvent(VM_EVENT_BIOS_INIT);

        TIMER_BIOS_INIT_Configure();

        void INT10_Startup(Section *sec);
        INT10_Startup(NULL);

        if (!IS_PC98_ARCH) {
            extern Bit8u BIOS_tandy_D4_flag;
            real_writeb(0x40,0xd4,BIOS_tandy_D4_flag);
        }

        /* INT 13 Bios Disk Support */
        BIOS_SetupDisks();

        /* INT 16 Keyboard handled in another file */
        BIOS_SetupKeyboard();

        if (!IS_PC98_ARCH) {
            int4b_callback.Set_RealVec(0x4B,/*reinstall*/true);
            callback[1].Set_RealVec(0x11,/*reinstall*/true);
            callback[2].Set_RealVec(0x12,/*reinstall*/true);
            callback[3].Set_RealVec(0x14,/*reinstall*/true);
            callback[4].Set_RealVec(0x15,/*reinstall*/true);
            callback[5].Set_RealVec(0x17,/*reinstall*/true);
            callback[6].Set_RealVec(0x1A,/*reinstall*/true);
            callback[7].Set_RealVec(0x1C,/*reinstall*/true);
            callback[8].Set_RealVec(0x70,/*reinstall*/true);
            callback[9].Set_RealVec(0x71,/*reinstall*/true);
            callback[10].Set_RealVec(0x19,/*reinstall*/true);
            callback[11].Set_RealVec(0x76,/*reinstall*/true);
            callback[12].Set_RealVec(0x77,/*reinstall*/true);
            callback[13].Set_RealVec(0x0E,/*reinstall*/true);
            callback[15].Set_RealVec(0x18,/*reinstall*/true);
        }

        // FIXME: We're using IBM PC memory size storage even in PC-98 mode.
        //        This cannot be removed, because the DOS kernel uses this variable even in PC-98 mode.
        mem_writew(BIOS_MEMORY_SIZE,t_conv);

        RealSetVec(0x08,BIOS_DEFAULT_IRQ0_LOCATION);
        // pseudocode for CB_IRQ0:
        //  sti
        //  callback INT8_Handler
        //  push ds,ax,dx
        //  int 0x1c
        //  cli
        //  mov al, 0x20
        //  out 0x20, al
        //  pop dx,ax,ds
        //  iret

        if (!IS_PC98_ARCH) {
            mem_writed(BIOS_TIMER,0);           //Calculate the correct time

            // INT 05h: Print Screen
            // IRQ1 handler calls it when PrtSc key is pressed; does nothing unless hooked
            phys_writeb(Real2Phys(BIOS_DEFAULT_INT5_LOCATION), 0xcf);
            RealSetVec(0x05, BIOS_DEFAULT_INT5_LOCATION);

            phys_writew(Real2Phys(RealGetVec(0x12))+0x12,0x20); //Hack for Jurresic
        }

        phys_writeb(Real2Phys(BIOS_DEFAULT_HANDLER_LOCATION),0xcf); /* bios default interrupt vector location -> IRET */

        if (!IS_PC98_ARCH) {
            // tandy DAC setup
            bool use_tandyDAC=(real_readb(0x40,0xd4)==0xff);

            tandy_sb.port=0;
            tandy_dac.port=0;
            if (use_tandyDAC) {
                /* tandy DAC sound requested, see if soundblaster device is available */
                Bitu tandy_dac_type = 0;
                if (Tandy_InitializeSB()) {
                    tandy_dac_type = 1;
                } else if (Tandy_InitializeTS()) {
                    tandy_dac_type = 2;
                }
                if (tandy_dac_type) {
                    real_writew(0x40,0xd0,0x0000);
                    real_writew(0x40,0xd2,0x0000);
                    real_writeb(0x40,0xd4,0xff);    /* tandy DAC init value */
                    real_writed(0x40,0xd6,0x00000000);
                    /* install the DAC callback handler */
                    tandy_DAC_callback[0]=new CALLBACK_HandlerObject();
                    tandy_DAC_callback[1]=new CALLBACK_HandlerObject();
                    tandy_DAC_callback[0]->Install(&IRQ_TandyDAC,CB_IRET,"Tandy DAC IRQ");
                    tandy_DAC_callback[1]->Install(NULL,CB_TDE_IRET,"Tandy DAC end transfer");
                    // pseudocode for CB_TDE_IRET:
                    //  push ax
                    //  mov ax, 0x91fb
                    //  int 15
                    //  cli
                    //  mov al, 0x20
                    //  out 0x20, al
                    //  pop ax
                    //  iret

                    Bit8u tandy_irq = 7;
                    if (tandy_dac_type==1) tandy_irq = tandy_sb.irq;
                    else if (tandy_dac_type==2) tandy_irq = tandy_dac.irq;
                    Bit8u tandy_irq_vector = tandy_irq;
                    if (tandy_irq_vector<8) tandy_irq_vector += 8;
                    else tandy_irq_vector += (0x70-8);

                    RealPt current_irq=RealGetVec(tandy_irq_vector);
                    real_writed(0x40,0xd6,current_irq);
                    for (Bit16u i=0; i<0x10; i++) phys_writeb(PhysMake(0xf000,0xa084+i),0x80);
                } else real_writeb(0x40,0xd4,0x00);
            }
        }

        if (!IS_PC98_ARCH) {
            /* Setup some stuff in 0x40 bios segment */

            // Disney workaround
            //      Bit16u disney_port = mem_readw(BIOS_ADDRESS_LPT1);
            // port timeouts
            // always 1 second even if the port does not exist
            //      BIOS_SetLPTPort(0, disney_port);
            for(Bitu i = 1; i < 3; i++) BIOS_SetLPTPort(i, 0);
            mem_writeb(BIOS_COM1_TIMEOUT,1);
            mem_writeb(BIOS_COM2_TIMEOUT,1);
            mem_writeb(BIOS_COM3_TIMEOUT,1);
            mem_writeb(BIOS_COM4_TIMEOUT,1);

            void BIOS_Post_register_parports();
            BIOS_Post_register_parports();

            void BIOS_Post_register_comports();
            BIOS_Post_register_comports();
        }

        if (!IS_PC98_ARCH) {
            /* Setup equipment list */
            // look http://www.bioscentral.com/misc/bda.htm

            //Bit16u config=0x4400; //1 Floppy, 2 serial and 1 parallel 
            Bit16u config = 0x0;

            config |= bios_post_parport_count() << 14;
            config |= bios_post_comport_count() << 9;

#if (C_FPU)
            extern bool enable_fpu;

            //FPU
            if (enable_fpu)
                config|=0x2;
#endif
            switch (machine) {
                case MCH_MDA:
                case MCH_HERC:
                    //Startup monochrome
                    config|=0x30;
                    break;
                case EGAVGA_ARCH_CASE:
                case MCH_CGA:
                case MCH_MCGA:
                case TANDY_ARCH_CASE:
                case MCH_AMSTRAD:
                    //Startup 80x25 color
                    config|=0x20;
                    break;
                default:
                    //EGA VGA
                    config|=0;
                    break;
            }

            // PS2 mouse
            if (KEYBOARD_Report_BIOS_PS2Mouse())
                config |= 0x04;

            // DMA *not* supported - Ancient Art of War CGA uses this to identify PCjr
            if (machine==MCH_PCJR) config |= 0x100;

            // Gameport
            config |= 0x1000;
            mem_writew(BIOS_CONFIGURATION,config);
            if (IS_EGAVGA_ARCH) config &= ~0x30; //EGA/VGA startup display mode differs in CMOS
            CMOS_SetRegister(0x14,(Bit8u)(config&0xff)); //Should be updated on changes
        }

        if (!IS_PC98_ARCH) {
            /* Setup extended memory size */
            IO_Write(0x70,0x30);
            size_extended=IO_Read(0x71);
            IO_Write(0x70,0x31);
            size_extended|=(IO_Read(0x71) << 8);
            BIOS_HostTimeSync();
        }
        else {
            /* Provide a valid memory size anyway */
            size_extended=MEM_TotalPages()*4;
            if (size_extended >= 1024) size_extended -= 1024;
            else size_extended = 0;
        }

        if (!IS_PC98_ARCH) {
            /* PS/2 mouse */
            void BIOS_PS2Mouse_Startup(Section *sec);
            BIOS_PS2Mouse_Startup(NULL);
        }

        if (!IS_PC98_ARCH) {
            /* this belongs HERE not on-demand from INT 15h! */
            biosConfigSeg = ROMBIOS_GetMemory(16/*one paragraph*/,"BIOS configuration (INT 15h AH=0xC0)",/*paragraph align*/16)>>4;
            if (biosConfigSeg != 0) {
                PhysPt data = PhysMake(biosConfigSeg,0);
                phys_writew(data,8);                        // 8 Bytes following
                if (IS_TANDY_ARCH) {
                    if (machine==MCH_TANDY) {
                        // Model ID (Tandy)
                        phys_writeb(data+2,0xFF);
                    } else {
                        // Model ID (PCJR)
                        phys_writeb(data+2,0xFD);
                    }
                    phys_writeb(data+3,0x0A);                   // Submodel ID
                    phys_writeb(data+4,0x10);                   // Bios Revision
                    /* Tandy doesn't have a 2nd PIC, left as is for now */
                    phys_writeb(data+5,(1<<6)|(1<<5)|(1<<4));   // Feature Byte 1
                } else {
                    if (machine==MCH_MCGA) {
                        /* PC/2 model 30 model */
                        phys_writeb(data+2,0xFA);
                        phys_writeb(data+3,0x00);                   // Submodel ID (PS/2) model 30
                    } else if (PS1AudioCard) { /* FIXME: Won't work because BIOS_Init() comes before PS1SOUND_Init() */
                        phys_writeb(data+2,0xFC);                   // Model ID (PC)
                        phys_writeb(data+3,0x0B);                   // Submodel ID (PS/1).
                    } else {
                        phys_writeb(data+2,0xFC);                   // Model ID (PC)
                        phys_writeb(data+3,0x00);                   // Submodel ID
                    }
                    phys_writeb(data+4,0x01);                   // Bios Revision
                    phys_writeb(data+5,(1<<6)|(1<<5)|(1<<4));   // Feature Byte 1
                }
                phys_writeb(data+6,(1<<6));             // Feature Byte 2
                phys_writeb(data+7,0);                  // Feature Byte 3
                phys_writeb(data+8,0);                  // Feature Byte 4
                phys_writeb(data+9,0);                  // Feature Byte 5
            }
        }

        // ISA Plug & Play I/O ports
        if (!IS_PC98_ARCH) {
            ISAPNP_PNP_ADDRESS_PORT = new IO_WriteHandleObject;
            ISAPNP_PNP_ADDRESS_PORT->Install(0x279,isapnp_write_port,IO_MB);
            ISAPNP_PNP_DATA_PORT = new IO_WriteHandleObject;
            ISAPNP_PNP_DATA_PORT->Install(0xA79,isapnp_write_port,IO_MB);
            ISAPNP_PNP_READ_PORT = new IO_ReadHandleObject;
            ISAPNP_PNP_READ_PORT->Install(ISA_PNP_WPORT,isapnp_read_port,IO_MB);
            LOG(LOG_MISC,LOG_DEBUG)("Registered ISA PnP read port at 0x%03x",ISA_PNP_WPORT);
        }

        if (enable_integration_device) {
            /* integration device callout */
            if (dosbox_int_iocallout == IO_Callout_t_none)
                dosbox_int_iocallout = IO_AllocateCallout(IO_TYPE_MB);
            if (dosbox_int_iocallout == IO_Callout_t_none)
                E_Exit("Failed to get dosbox integration IO callout handle");

            {
                IO_CalloutObject *obj = IO_GetCallout(dosbox_int_iocallout);
                if (obj == NULL) E_Exit("Failed to get dosbox integration IO callout");

                /* NTS: Ports 28h-2Bh conflict with extended DMA control registers in PC-98 mode.
                 *      TODO: Move again, if DB28h-DB2Bh are taken by something standard on PC-98. */
                obj->Install(IS_PC98_ARCH ? 0xDB28 : 0x28,
                    IOMASK_Combine(IOMASK_FULL,IOMASK_Range(4)),dosbox_integration_cb_port_r,dosbox_integration_cb_port_w);
                IO_PutCallout(obj);
            }

            /* DOSBox integration device */
            if (!IS_PC98_ARCH && isapnpigdevice == NULL && enable_integration_device_pnp) {
                isapnpigdevice = new ISAPnPIntegrationDevice;
                ISA_PNP_devreg(isapnpigdevice);
            }
        }

        // ISA Plug & Play BIOS entrypoint
        // NTS: Apparently, Windows 95, 98, and ME will re-enumerate and re-install PnP devices if our entry point changes it's address.
        if (!IS_PC98_ARCH && ISAPNPBIOS) {
            Bitu base;
            unsigned int i;
            unsigned char c,tmp[256];

            isapnp_biosstruct_base = base = ROMBIOS_GetMemory(0x21,"ISA Plug & Play BIOS struct",/*paragraph alignment*/0x10);

            if (base == 0) E_Exit("Unable to allocate ISA PnP struct");
            LOG_MSG("ISA Plug & Play BIOS enabled");

            call_pnp_r = CALLBACK_Allocate();
            call_pnp_rp = PNPentry_real = CALLBACK_RealPointer(call_pnp_r);
            CALLBACK_Setup(call_pnp_r,ISAPNP_Handler_RM,CB_RETF,"ISA Plug & Play entry point (real)");
            //LOG_MSG("real entry pt=%08lx\n",PNPentry_real);

            call_pnp_p = CALLBACK_Allocate();
            call_pnp_pp = PNPentry_prot = CALLBACK_RealPointer(call_pnp_p);
            CALLBACK_Setup(call_pnp_p,ISAPNP_Handler_PM,CB_RETF,"ISA Plug & Play entry point (protected)");
            //LOG_MSG("prot entry pt=%08lx\n",PNPentry_prot);

            phys_writeb(base+0,'$');
            phys_writeb(base+1,'P');
            phys_writeb(base+2,'n');
            phys_writeb(base+3,'P');
            phys_writeb(base+4,0x10);       /* Version:     1.0 */
            phys_writeb(base+5,0x21);       /* Length:      0x21 bytes */
            phys_writew(base+6,0x0000);     /* Control field:   Event notification not supported */
            /* skip checksum atm */
            phys_writed(base+9,0);          /* Event notify flag addr: (none) */
            phys_writed(base+0xD,call_pnp_rp);  /* Real-mode entry point */
            phys_writew(base+0x11,call_pnp_pp&0xFFFF); /* Protected mode offset */
            phys_writed(base+0x13,(call_pnp_pp >> 12) & 0xFFFF0); /* Protected mode code segment base */
            phys_writed(base+0x17,ISAPNP_ID('D','O','S',0,8,3,0));      /* OEM device identifier (DOSBox-X 0.83.x) */
            phys_writew(base+0x1B,0xF000);      /* real-mode data segment */
            phys_writed(base+0x1D,0xF0000);     /* protected mode data segment address */
            /* run checksum */
            c=0;
            for (i=0;i < 0x21;i++) {
                if (i != 8) c += phys_readb(base+i);
            }
            phys_writeb(base+8,0x100-c);        /* checksum value: set so that summing bytes across the struct == 0 */

            /* input device (keyboard) */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_Keyboard,sizeof(ISAPNP_sysdev_Keyboard),true))
                LOG_MSG("ISAPNP register failed\n");

            /* input device (mouse) */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_Mouse,sizeof(ISAPNP_sysdev_Mouse),true))
                LOG_MSG("ISAPNP register failed\n");

            /* DMA controller */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_DMA_Controller,sizeof(ISAPNP_sysdev_DMA_Controller),true))
                LOG_MSG("ISAPNP register failed\n");

            /* Interrupt controller */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_PIC,sizeof(ISAPNP_sysdev_PIC),true))
                LOG_MSG("ISAPNP register failed\n");

            /* Timer */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_Timer,sizeof(ISAPNP_sysdev_Timer),true))
                LOG_MSG("ISAPNP register failed\n");

            /* Realtime clock */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_RTC,sizeof(ISAPNP_sysdev_RTC),true))
                LOG_MSG("ISAPNP register failed\n");

            /* PC speaker */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_PC_Speaker,sizeof(ISAPNP_sysdev_PC_Speaker),true))
                LOG_MSG("ISAPNP register failed\n");

            /* System board */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_System_Board,sizeof(ISAPNP_sysdev_System_Board),true))
                LOG_MSG("ISAPNP register failed\n");

            /* Motherboard PNP resources and general */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_General_ISAPNP,sizeof(ISAPNP_sysdev_General_ISAPNP),true))
                LOG_MSG("ISAPNP register failed\n");

            /* ISA bus, meaning, a computer with ISA slots.
             * The purpose of this device is to convince Windows 95 to automatically install it's
             * "ISA Plug and Play bus" so that PnP devices are recognized automatically */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_ISA_BUS,sizeof(ISAPNP_sysdev_ISA_BUS),true))
                LOG_MSG("ISAPNP register failed\n");

            if (pcibus_enable) {
                /* PCI bus, meaning, a computer with PCI slots.
                 * The purpose of this device is to tell Windows 95 that a PCI bus is present. Without
                 * this entry, PCI devices will not be recognized until you manually install the PCI driver. */
                if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_PCI_BUS,sizeof(ISAPNP_sysdev_PCI_BUS),true))
                    LOG_MSG("ISAPNP register failed\n");
            }

            /* APM BIOS device. To help Windows 95 see our APM BIOS. */
            if (APMBIOS && APMBIOS_pnp) {
                LOG_MSG("Registering APM BIOS as ISA Plug & Play BIOS device node");
                if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_APM_BIOS,sizeof(ISAPNP_sysdev_APM_BIOS),true))
                    LOG_MSG("ISAPNP register failed\n");
            }

#if (C_FPU)
            /* Numeric Coprocessor */
            if (!ISAPNP_RegisterSysDev(ISAPNP_sysdev_Numeric_Coprocessor,sizeof(ISAPNP_sysdev_Numeric_Coprocessor),true))
                LOG_MSG("ISAPNP register failed\n");
#endif

            /* RAM resources. we have to construct it */
            /* NTS: We don't do this here, but I have an old Toshiba laptop who's PnP BIOS uses
             *      this device ID to report both RAM and ROM regions. */
            {
                Bitu max = MEM_TotalPages() * 4096;
                const unsigned char h1[9] = {
                    ISAPNP_SYSDEV_HEADER(
                        ISAPNP_ID('P','N','P',0x0,0xC,0x0,0x1), /* PNP0C01 System device, motherboard resources */
                        ISAPNP_TYPE(0x05,0x00,0x00),        /* type: Memory, RAM, general */
                        0x0001 | 0x0002)
                };

                i = 0;
                memcpy(tmp+i,h1,9); i += 9;         /* can't disable, can't configure */
                /*----------allocated--------*/
                tmp[i+0] = 0x80 | 6;                /* 32-bit memory range */
                tmp[i+1] = 9;                   /* length=9 */
                tmp[i+2] = 0;
                tmp[i+3] = 0x01;                /* writeable, no cache, 8-bit, not shadowable, not ROM */
                host_writed(tmp+i+4,0x00000);           /* base */
                host_writed(tmp+i+8,max > 0xA0000 ? 0xA0000 : 0x00000); /* length */
                i += 9+3;

                if (max > 0x100000) {
                    tmp[i+0] = 0x80 | 6;                /* 32-bit memory range */
                    tmp[i+1] = 9;                   /* length=9 */
                    tmp[i+2] = 0;
                    tmp[i+3] = 0x01;
                    host_writed(tmp+i+4,0x100000);          /* base */
                    host_writed(tmp+i+8,max-0x100000);      /* length */
                    i += 9+3;
                }

                tmp[i+0] = 0x79;                /* END TAG */
                tmp[i+1] = 0x00;
                i += 2;
                /*-------------possible-----------*/
                tmp[i+0] = 0x79;                /* END TAG */
                tmp[i+1] = 0x00;
                i += 2;
                /*-------------compatible---------*/
                tmp[i+0] = 0x79;                /* END TAG */
                tmp[i+1] = 0x00;
                i += 2;

                if (!ISAPNP_RegisterSysDev(tmp,i))
                    LOG_MSG("ISAPNP register failed\n");
            }

            /* register parallel ports */
            for (Bitu portn=0;portn < 3;portn++) {
                Bitu port = mem_readw(BIOS_ADDRESS_LPT1+(portn*2));
                if (port != 0) {
                    const unsigned char h1[9] = {
                        ISAPNP_SYSDEV_HEADER(
                            ISAPNP_ID('P','N','P',0x0,0x4,0x0,0x0), /* PNP0400 Standard LPT printer port */
                            ISAPNP_TYPE(0x07,0x01,0x00),        /* type: General parallel port */
                            0x0001 | 0x0002)
                    };

                    i = 0;
                    memcpy(tmp+i,h1,9); i += 9;         /* can't disable, can't configure */
                    /*----------allocated--------*/
                    tmp[i+0] = (8 << 3) | 7;            /* IO resource */
                    tmp[i+1] = 0x01;                /* 16-bit decode */
                    host_writew(tmp+i+2,port);          /* min */
                    host_writew(tmp+i+4,port);          /* max */
                    tmp[i+6] = 0x10;                /* align */
                    tmp[i+7] = 0x03;                /* length */
                    i += 7+1;

                    /* TODO: If/when LPT emulation handles the IRQ, add IRQ resource here */

                    tmp[i+0] = 0x79;                /* END TAG */
                    tmp[i+1] = 0x00;
                    i += 2;
                    /*-------------possible-----------*/
                    tmp[i+0] = 0x79;                /* END TAG */
                    tmp[i+1] = 0x00;
                    i += 2;
                    /*-------------compatible---------*/
                    tmp[i+0] = 0x79;                /* END TAG */
                    tmp[i+1] = 0x00;
                    i += 2;

                    if (!ISAPNP_RegisterSysDev(tmp,i))
                        LOG_MSG("ISAPNP register failed\n");
                }
            }

            void BIOS_Post_register_comports_PNP();
            BIOS_Post_register_comports_PNP();

            void BIOS_Post_register_IDE();
            BIOS_Post_register_IDE();

            void BIOS_Post_register_FDC();
            BIOS_Post_register_FDC();
        }

        if (IS_PC98_ARCH) {
            /* initialize IRQ0 timer to default tick interval.
             * PC-98 does not pre-initialize timer 0 of the PIT to 0xFFFF the way IBM PC/XT/AT do */
            PC98_Interval_Timer_Continue();
            PIC_SetIRQMask(0,true); /* PC-98 keeps the timer off unless INT 1Ch is called to set a timer interval */
        }

        if (!IS_PC98_ARCH) {
            Section_prop * section=static_cast<Section_prop *>(control->GetSection("speaker"));
            bool bit0en = section->Get_bool("pcspeaker clock gate enable at startup");

            if (bit0en) {
                Bit8u x = IO_Read(0x61);
                IO_Write(0x61,(x & (~3u)) | 1u); /* set bits[1:0] = 01  (clock gate enable but output gate disable) */
                LOG_MSG("xxxx");
            }
        }

        CPU_STI();

        return CBRET_NONE;
    }
    CALLBACK_HandlerObject cb_bios_scan_video_bios;
    static Bitu cb_bios_scan_video_bios__func(void) {
        unsigned long size;

        /* NTS: As far as I can tell, video is integrated into the PC-98 BIOS and there is no separate BIOS */
        if (IS_PC98_ARCH) return CBRET_NONE;

        if (cpu.pmode) E_Exit("BIOS error: VIDEO BIOS SCAN function called while in protected/vm86 mode");

        if (!bios_has_exec_vga_bios) {
            bios_has_exec_vga_bios = true;
            if (IS_EGAVGA_ARCH) {
                /* make sure VGA BIOS is there at 0xC000:0x0000 */
                if (AdapterROM_Read(0xC0000,&size)) {
                    LOG(LOG_MISC,LOG_DEBUG)("BIOS VIDEO ROM SCAN found VGA BIOS (size=%lu)",size);
                    adapter_scan_start = 0xC0000 + size;

                    // step back into the callback instruction that triggered this call
                    reg_eip -= 4;

                    // FAR CALL into the VGA BIOS
                    CPU_CALL(false,0xC000,0x0003,reg_eip);
                    return CBRET_NONE;
                }
                else {
                    LOG(LOG_MISC,LOG_WARN)("BIOS VIDEO ROM SCAN did not find VGA BIOS");
                }
            }
            else {
                // CGA, MDA, Tandy, PCjr. No video BIOS to scan for
            }
        }

        return CBRET_NONE;
    }
    CALLBACK_HandlerObject cb_bios_adapter_rom_scan;
    static Bitu cb_bios_adapter_rom_scan__func(void) {
        unsigned long size;
        Bit32u c1;

        /* FIXME: I have no documentation on how PC-98 scans for adapter ROM or even if it supports it */
        if (IS_PC98_ARCH) return CBRET_NONE;

        if (cpu.pmode) E_Exit("BIOS error: ADAPTER ROM function called while in protected/vm86 mode");

        while (adapter_scan_start < 0xF0000) {
            if (AdapterROM_Read(adapter_scan_start,&size)) {
                Bit16u segm = (Bit16u)(adapter_scan_start >> 4);

                LOG(LOG_MISC,LOG_DEBUG)("BIOS ADAPTER ROM scan found ROM at 0x%lx (size=%lu)",(unsigned long)adapter_scan_start,size);

                c1 = mem_readd(adapter_scan_start+3);
                adapter_scan_start += size;
                if (c1 != 0UL) {
                    LOG(LOG_MISC,LOG_DEBUG)("Running ADAPTER ROM entry point");

                    // step back into the callback instruction that triggered this call
                    reg_eip -= 4;

                    // FAR CALL into the VGA BIOS
                    CPU_CALL(false,segm,0x0003,reg_eip);
                    return CBRET_NONE;
                }
                else {
                    LOG(LOG_MISC,LOG_DEBUG)("FIXME: ADAPTER ROM entry point does not exist");
                }
            }
            else {
                if (IS_EGAVGA_ARCH) // supposedly newer systems only scan on 2KB boundaries by standard? right?
                    adapter_scan_start = (adapter_scan_start | 2047UL) + 1UL;
                else // while older PC/XT systems scanned on 512-byte boundaries? right?
                    adapter_scan_start = (adapter_scan_start | 511UL) + 1UL;
            }
        }

        LOG(LOG_MISC,LOG_DEBUG)("BIOS ADAPTER ROM scan complete");
        return CBRET_NONE;
    }
    CALLBACK_HandlerObject cb_bios_startup_screen;
    static Bitu cb_bios_startup_screen__func(void) {
        const char *msg = PACKAGE_STRING " (C) 2002-" COPYRIGHT_END_YEAR " The DOSBox Team\nA fork of DOSBox 0.74 by TheGreatCodeholio\nFor more info visit http://dosbox-x.com\nBased on DOSBox (http://dosbox.com)\n\n";
        int logo_x,logo_y,x,y,rowheight=8;

        y = 2;
        x = 2;
        logo_y = 2;
        logo_x = 80 - 2 - (224/8);

        if (cpu.pmode) E_Exit("BIOS error: STARTUP function called while in protected/vm86 mode");

        // TODO: For those who would rather not use the VGA graphical modes, add a configuration option to "disable graphical splash".
        //       We would then revert to a plain text copyright and status message here (and maybe an ASCII art version of the DOSBox logo).
        if (IS_VGA_ARCH) {
            rowheight = 16;
            reg_eax = 18;       // 640x480 16-color
            CALLBACK_RunRealInt(0x10);
            DrawDOSBoxLogoVGA((unsigned int)logo_x*8u,(unsigned int)logo_y*(unsigned int)rowheight);
        }
        else if (machine == MCH_EGA) {
            rowheight = 14;
            reg_eax = 16;       // 640x350 16-color
            CALLBACK_RunRealInt(0x10);

            // color correction: change Dark Puke Yellow to brown
            IO_Read(0x3DA); IO_Read(0x3BA);
            IO_Write(0x3C0,0x06);
            IO_Write(0x3C0,0x14); // red=1 green=1 blue=0
            IO_Read(0x3DA); IO_Read(0x3BA);
            IO_Write(0x3C0,0x20);

            DrawDOSBoxLogoVGA((unsigned int)logo_x*8u,(unsigned int)logo_y*(unsigned int)rowheight);
        }
        else if (machine == MCH_CGA || machine == MCH_MCGA || machine == MCH_PCJR || machine == MCH_AMSTRAD || machine == MCH_TANDY) {
            rowheight = 8;
            reg_eax = 6;        // 640x200 2-color
            CALLBACK_RunRealInt(0x10);

            DrawDOSBoxLogoCGA6((unsigned int)logo_x*8u,(unsigned int)logo_y*(unsigned int)rowheight);
        }
        else if (machine == MCH_PC98) {
            // clear the graphics layer
            for (unsigned int i=0;i < (80*400);i++) {
                mem_writeb(0xA8000+i,0);        // B
                mem_writeb(0xB0000+i,0);        // G
                mem_writeb(0xB8000+i,0);        // R
                mem_writeb(0xE0000+i,0);        // E
            }

            reg_eax = 0x0C00;   // enable text layer (PC-98)
            CALLBACK_RunRealInt(0x18);

            reg_eax = 0x1100;   // show cursor (PC-98)
            CALLBACK_RunRealInt(0x18);

            reg_eax = 0x1300;   // set cursor pos (PC-98)
            reg_edx = 0x0000;   // byte position
            CALLBACK_RunRealInt(0x18);

            bios_pc98_posx = x;

            reg_eax = 0x4200;   // setup 640x400 graphics
            reg_ecx = 0xC000;
            CALLBACK_RunRealInt(0x18);

            // enable the 4th bitplane, for 16-color analog graphics mode.
            // TODO: When we allow the user to emulate only the 8-color BGR digital mode,
            //       logo drawing should use an alternate drawing method.
            IO_Write(0x6A,0x01);    // enable 16-color analog mode (this makes the 4th bitplane appear)
            IO_Write(0x6A,0x04);    // but we don't need the EGC graphics
            // If we caught a game mid-page flip, set the display and VRAM pages back to zero
            IO_Write(0xA4,0x00);    // display page 0
            IO_Write(0xA6,0x00);    // write to page 0

            // program a VGA-like color palette so we can re-use the VGA logo
            for (unsigned int i=0;i < 16;i++) {
                unsigned int bias = (i & 8) ? 0x5 : 0x0;

                IO_Write(0xA8,i);   // DAC index
                if (i != 6) {
                    IO_Write(0xAA,((i & 2) ? 0xA : 0x0) + bias);    // green
                    IO_Write(0xAC,((i & 4) ? 0xA : 0x0) + bias);    // red
                    IO_Write(0xAE,((i & 1) ? 0xA : 0x0) + bias);    // blue
                }
                else { // brown #6 instead of puke yellow
                    IO_Write(0xAA, 0x5 + bias);    // green
                    IO_Write(0xAC, 0xA + bias);    // red
                    IO_Write(0xAE, 0x0 + bias);    // blue
                }
            }

            DrawDOSBoxLogoPC98((unsigned int)logo_x*8u,(unsigned int)logo_y*(unsigned int)rowheight);

            reg_eax = 0x4000;   // show the graphics layer (PC-98) so we can render the DOSBox logo
            CALLBACK_RunRealInt(0x18);
        }
        else {
            reg_eax = 3;        // 80x25 text
            CALLBACK_RunRealInt(0x10);

            // TODO: For CGA, PCjr, and Tandy, we could render a 4-color CGA version of the same logo.
            //       And for MDA/Hercules, we could render a monochromatic ASCII art version.
        }

        if (machine != MCH_PC98) {
            reg_eax = 0x0200;   // set cursor pos
            reg_ebx = 0;        // page zero
            reg_dh = y;     // row 4
            reg_dl = x;     // column 20
            CALLBACK_RunRealInt(0x10);
        }

        BIOS_Int10RightJustifiedPrint(x,y,msg);

        {
            uint64_t sz = (uint64_t)MEM_TotalPages() * (uint64_t)4096;
            char tmp[512];

            if (sz >= ((uint64_t)128 << (uint64_t)20))
                sprintf(tmp,"%uMB memory installed\r\n",(unsigned int)(sz >> (uint64_t)20));
            else
                sprintf(tmp,"%uKB memory installed\r\n",(unsigned int)(sz >> (uint64_t)10));

            BIOS_Int10RightJustifiedPrint(x,y,tmp);
        }

        {
            char tmp[512];
            const char *card = "?";

            switch (machine) {
                case MCH_CGA:
                    card = "IBM Color Graphics Adapter";
                    break;
                case MCH_MCGA:
                    card = "IBM Multi Color Graphics Adapter";
                    break;
                case MCH_MDA:
                    card = "IBM Monochrome Display Adapter";
                    break;
                case MCH_HERC:
                    card = "IBM Monochrome Display Adapter (Hercules)";
                    break;
                case MCH_EGA:
                    card = "IBM Enhanced Graphics Adapter";
                    break;
                case MCH_PCJR:
                    card = "PCjr graohics adapter";
                    break;
                case MCH_TANDY:
                    card = "Tandy graohics adapter";
                    break;
                case MCH_VGA:
                    switch (svgaCard) {
                        case SVGA_TsengET4K:
                            card = "Tseng ET4000 SVGA";
                            break;
                        case SVGA_TsengET3K:
                            card = "Tseng ET3000 SVGA";
                            break;
                        case SVGA_ParadisePVGA1A:
                            card = "Paradise SVGA";
                            break;
                        case SVGA_S3Trio:
                            card = "S3 Trio SVGA";
                            break;
                        default:
                            card = "Standard VGA";
                            break;
                    }

                    break;
                case MCH_PC98:
                    card = "PC98 graphics";
                    break;
                case MCH_AMSTRAD:
                    card = "Amstrad graphics";
                    break;
                default:
                    abort(); // should not happen
            }

            sprintf(tmp,"Video card is %s\n",card);
            BIOS_Int10RightJustifiedPrint(x,y,tmp);
        }

        {
            char tmp[512];
            const char *cpuType = "?";

            switch (CPU_ArchitectureType) {
                case CPU_ARCHTYPE_8086:
                    cpuType = "8086";
                    break;
                case CPU_ARCHTYPE_80186:
                    cpuType = "80186";
                    break;
                case CPU_ARCHTYPE_286:
                    cpuType = "286";
                    break;
                case CPU_ARCHTYPE_386:
                    cpuType = "386";
                    break;
                case CPU_ARCHTYPE_486OLD:
                    cpuType = "486 (older generation)";
                    break;
                case CPU_ARCHTYPE_486NEW:
                    cpuType = "486 (later generation)";
                    break;
                case CPU_ARCHTYPE_PENTIUM:
                    cpuType = "Pentium";
                    break;
                case CPU_ARCHTYPE_PMMXSLOW:
                    cpuType = "Pentium MMX";
                    break;
                case CPU_ARCHTYPE_MIXED:
                    cpuType = "Auto (mixed)";
                    break;
            }

            extern bool enable_fpu;

            sprintf(tmp,"%s CPU present",cpuType);
            BIOS_Int10RightJustifiedPrint(x,y,tmp);
            if (enable_fpu) BIOS_Int10RightJustifiedPrint(x,y," with FPU");
            BIOS_Int10RightJustifiedPrint(x,y,"\n");
        }

        if (APMBIOS) {
            BIOS_Int10RightJustifiedPrint(x,y,"Advanced Power Management interface active\n");
        }

        if (ISAPNPBIOS) {
            BIOS_Int10RightJustifiedPrint(x,y,"ISA Plug & Play BIOS active\n");
        }

#if !defined(C_EMSCRIPTEN)
        BIOS_Int10RightJustifiedPrint(x,y,"\nHit SPACEBAR to pause at this screen\n");
        y--; /* next message should overprint */
        if (machine != MCH_PC98) {
            reg_eax = 0x0200;   // set cursor pos
            reg_ebx = 0;        // page zero
            reg_dh = y;     // row 4
            reg_dl = x;     // column 20
            CALLBACK_RunRealInt(0x10);
        }
        else {
            reg_eax = 0x1300u;   // set cursor pos (PC-98)
            reg_edx = (((unsigned int)y * 80u) + (unsigned int)x) * 2u; // byte position
            CALLBACK_RunRealInt(0x18);
        }
#endif

        // TODO: Then at this screen, we can print messages demonstrating the detection of
        //       IDE devices, floppy, ISA PnP initialization, anything of importance.
        //       I also envision adding the ability to hit DEL or F2 at this point to enter
        //       a "BIOS setup" screen where all DOSBox configuration options can be
        //       modified, with the same look and feel of an old BIOS.

#if C_EMSCRIPTEN
        Bit32u lasttick=GetTicks();
        while ((GetTicks()-lasttick)<1000) {
            void CALLBACK_Idle(void);
            CALLBACK_Idle();
            emscripten_sleep_with_yield(100);
        }
#else
        if (!control->opt_fastbioslogo) {
            bool wait_for_user = false;
            Bit32u lasttick=GetTicks();
            while ((GetTicks()-lasttick)<1000) {
                if (machine == MCH_PC98) {
                    reg_eax = 0x0100;   // sense key
                    CALLBACK_RunRealInt(0x18);
                    SETFLAGBIT(ZF,reg_bh == 0);
                }
                else {
                    reg_eax = 0x0100;
                    CALLBACK_RunRealInt(0x16);
                }

                if (!GETFLAG(ZF)) {
                    if (machine == MCH_PC98) {
                        reg_eax = 0x0000;   // read key
                        CALLBACK_RunRealInt(0x18);
                    }
                    else {
                        reg_eax = 0x0000;
                        CALLBACK_RunRealInt(0x16);
                    }

                    if (reg_al == 32) { // user hit space
                        BIOS_Int10RightJustifiedPrint(x,y,"Hit ENTER or ESC to continue                    \n"); // overprint
                        wait_for_user = true;
                        break;
                    }
                }
            }

            while (wait_for_user) {
                if (machine == MCH_PC98) {
                    reg_eax = 0x0000;   // read key
                    CALLBACK_RunRealInt(0x18);
                }
                else {
                    reg_eax = 0x0000;
                    CALLBACK_RunRealInt(0x16);
                }

                if (reg_al == 27/*ESC*/ || reg_al == 13/*ENTER*/)
                    break;
            }
        }
#endif

        if (machine == MCH_PC98) {
            reg_eax = 0x4100;   // hide the graphics layer (PC-98)
            CALLBACK_RunRealInt(0x18);

            // clear the graphics layer
            for (unsigned int i=0;i < (80*400);i++) {
                mem_writeb(0xA8000+i,0);        // B
                mem_writeb(0xB0000+i,0);        // G
                mem_writeb(0xB8000+i,0);        // R
                mem_writeb(0xE0000+i,0);        // E
            }

            IO_Write(0x6A,0x00);    // switch back to 8-color mode

            reg_eax = 0x4200;   // setup 640x200 graphics
            reg_ecx = 0x8000;   // lower
            CALLBACK_RunRealInt(0x18);
        }
        else {
            // restore 80x25 text mode
            reg_eax = 3;
            CALLBACK_RunRealInt(0x10);
        }

        return CBRET_NONE;
    }
    CALLBACK_HandlerObject cb_bios_boot;
    CALLBACK_HandlerObject cb_bios_bootfail;
    CALLBACK_HandlerObject cb_pc98_rombasic;
    static Bitu cb_pc98_entry__func(void) {
        /* the purpose of this function is to say "N88 ROM BASIC NOT FOUND" */
        int x,y;

        x = y = 0;

        /* PC-98 MS-DOS boot sector may RETF back to the BIOS, and this is where execution ends up */
        BIOS_Int10RightJustifiedPrint(x,y,"N88 ROM BASIC NOT IMPLEMENTED");

        return CBRET_NONE;
    }
    static Bitu cb_bios_bootfail__func(void) {
        int x,y;

        x = y = 0;

        /* PC-98 MS-DOS boot sector may RETF back to the BIOS, and this is where execution ends up */
        BIOS_Int10RightJustifiedPrint(x,y,"Guest OS failed to boot, returned failure");

        /* and then after this call, there is a JMP $ to loop endlessly */
        return CBRET_NONE;
    }
    static Bitu cb_bios_boot__func(void) {
        /* Reset/power-on overrides the user's A20 gate preferences.
         * It's time to revert back to what the user wants. */
        void A20Gate_TakeUserSetting(Section *sec);
        void MEM_A20_Enable(bool enabled);
        A20Gate_TakeUserSetting(NULL);
        MEM_A20_Enable(false);

        if (cpu.pmode) E_Exit("BIOS error: BOOT function called while in protected/vm86 mode");
        DispatchVMEvent(VM_EVENT_BIOS_BOOT);

        // TODO: If instructed to, follow the INT 19h boot pattern, perhaps follow the BIOS Boot Specification, etc.

        // TODO: If instructed to boot a guest OS...

        /* wipe out the stack so it's not there to interfere with the system */
        reg_esp = 0;
        reg_eip = 0;
        CPU_SetSegGeneral(cs, 0x60);
        CPU_SetSegGeneral(ss, 0x60);

        for (Bitu i=0;i < 0x400;i++) mem_writeb(0x7C00+i,0);

        // Begin booting the DOSBox shell. NOTE: VM_Boot_DOSBox_Kernel will change CS:IP instruction pointer!
        if (!VM_Boot_DOSBox_Kernel()) E_Exit("BIOS error: BOOT function failed to boot DOSBox kernel");
        return CBRET_NONE;
    }
public:
    void write_FFFF_signature() {
        /* write the signature at 0xF000:0xFFF0 */

        // The farjump at the processor reset entry point (jumps to POST routine)
        phys_writeb(0xffff0,0xEA);                  // FARJMP
        phys_writew(0xffff1,RealOff(BIOS_DEFAULT_RESET_LOCATION));  // offset
        phys_writew(0xffff3,RealSeg(BIOS_DEFAULT_RESET_LOCATION));  // segment

        // write system BIOS date
        for(Bitu i = 0; i < strlen(bios_date_string); i++) phys_writeb(0xffff5+i,(Bit8u)bios_date_string[i]);

        /* model byte */
        if (machine==MCH_TANDY || machine==MCH_AMSTRAD) phys_writeb(0xffffe,0xff);  /* Tandy model */
        else if (machine==MCH_PCJR) phys_writeb(0xffffe,0xfd);  /* PCJr model */
        else if (machine==MCH_MCGA) phys_writeb(0xffffe,0xfa);  /* PC/2 model 30 model */
        else phys_writeb(0xffffe,0xfc); /* PC (FIXME: This is listed as model byte PS/2 model 60) */

        // signature
        phys_writeb(0xfffff,0x55);
    }
    BIOS(Section* configuration):Module_base(configuration){
        isapnp_biosstruct_base = 0;

        { // TODO: Eventually, move this to BIOS POST or init phase
            Section_prop * section=static_cast<Section_prop *>(control->GetSection("dosbox"));
                        Section_prop * pc98_section=static_cast<Section_prop *>(control->GetSection("pc98"));

            enable_pc98_copyright_string = pc98_section->Get_bool("pc-98 BIOS copyright string");

            // NTS: This setting is also valid in PC-98 mode. According to Undocumented PC-98 by Webtech,
            //      there's nothing at I/O port E9h. I will move the I/O port in PC-98 mode if there is in
            //      fact a conflict. --J.C.
            bochs_port_e9 = section->Get_bool("bochs debug port e9");

            // TODO: motherboard init, especially when we get around to full Intel Triton/i440FX chipset emulation
            isa_memory_hole_512kb = section->Get_bool("isa memory hole at 512kb");

            // FIXME: Erm, well this couldv'e been named better. It refers to the amount of conventional memory
            //        made available to the operating system below 1MB, which is usually DOS.
            dos_conventional_limit = (unsigned int)section->Get_int("dos mem limit");

            // for PC-98: When accessing the floppy through INT 1Bh, when enabled, run through a waiting loop to make sure
            //     the timer count is not too high on exit (Ys II)
            enable_fdc_timer_hack = pc98_section->Get_bool("pc-98 int 1b fdc timer wait");

            {
                std::string s = section->Get_string("unhandled irq handler");

                if (s == "simple")
                    unhandled_irq_method = UNHANDLED_IRQ_SIMPLE;
                else if (s == "cooperative_2nd")
                    unhandled_irq_method = UNHANDLED_IRQ_COOPERATIVE_2ND;
                // pick default
                else if (IS_PC98_ARCH)
                    unhandled_irq_method = UNHANDLED_IRQ_COOPERATIVE_2ND;
                else
                    unhandled_irq_method = UNHANDLED_IRQ_SIMPLE;
            }
        }

        if (bochs_port_e9) {
            if (BOCHS_PORT_E9 == NULL) {
                BOCHS_PORT_E9 = new IO_WriteHandleObject;
                BOCHS_PORT_E9->Install(0xE9,bochs_port_e9_write,IO_MB);
            }
            LOG(LOG_MISC,LOG_DEBUG)("Bochs port E9h emulation is active");
        }
        else {
            if (BOCHS_PORT_E9 != NULL) {
                delete BOCHS_PORT_E9;
                BOCHS_PORT_E9 = NULL;
            }
        }

        /* pick locations */
        BIOS_DEFAULT_RESET_LOCATION = PhysToReal416(ROMBIOS_GetMemory(64/*several callbacks*/,"BIOS default reset location",/*align*/4));
        BIOS_DEFAULT_HANDLER_LOCATION = PhysToReal416(ROMBIOS_GetMemory(1/*IRET*/,"BIOS default handler location",/*align*/4));
        BIOS_DEFAULT_INT5_LOCATION = PhysToReal416(ROMBIOS_GetMemory(1/*IRET*/, "BIOS default INT5 location",/*align*/4));
        BIOS_DEFAULT_IRQ0_LOCATION = PhysToReal416(ROMBIOS_GetMemory(0x13/*see callback.cpp for IRQ0*/,"BIOS default IRQ0 location",/*align*/4));
        BIOS_DEFAULT_IRQ1_LOCATION = PhysToReal416(ROMBIOS_GetMemory(0x20/*see callback.cpp for IRQ1*/,"BIOS default IRQ1 location",/*align*/4));
        BIOS_DEFAULT_IRQ07_DEF_LOCATION = PhysToReal416(ROMBIOS_GetMemory(7/*see callback.cpp for EOI_PIC1*/,"BIOS default IRQ2-7 location",/*align*/4));
        BIOS_DEFAULT_IRQ815_DEF_LOCATION = PhysToReal416(ROMBIOS_GetMemory(9/*see callback.cpp for EOI_PIC1*/,"BIOS default IRQ8-15 location",/*align*/4));

        write_FFFF_signature();

        /* Setup all the interrupt handlers the bios controls */

        /* INT 8 Clock IRQ Handler */
        call_irq0=CALLBACK_Allocate();
        if (IS_PC98_ARCH)
            CALLBACK_Setup(call_irq0,INT8_PC98_Handler,CB_IRET,Real2Phys(BIOS_DEFAULT_IRQ0_LOCATION),"IRQ 0 Clock");
        else
            CALLBACK_Setup(call_irq0,INT8_Handler,CB_IRQ0,Real2Phys(BIOS_DEFAULT_IRQ0_LOCATION),"IRQ 0 Clock");

        /* INT 11 Get equipment list */
        callback[1].Install(&INT11_Handler,CB_IRET,"Int 11 Equipment");

        /* INT 12 Memory Size default at 640 kb */
        callback[2].Install(&INT12_Handler,CB_IRET,"Int 12 Memory");

        ulimit = 640;
        t_conv = MEM_TotalPages() << 2; /* convert 4096/byte pages -> 1024/byte KB units */
        if (allow_more_than_640kb) {
            if (machine == MCH_CGA)
                ulimit = 736;       /* 640KB + 64KB + 32KB  0x00000-0xB7FFF */
            else if (machine == MCH_HERC || machine == MCH_MDA)
                ulimit = 704;       /* 640KB + 64KB = 0x00000-0xAFFFF */

            if (t_conv > ulimit) t_conv = ulimit;
            if (t_conv > 640) { /* because the memory emulation has already set things up */
                bool MEM_map_RAM_physmem(Bitu start,Bitu end);
                MEM_map_RAM_physmem(0xA0000,(t_conv<<10)-1);
                memset(GetMemBase()+(640<<10),0,(t_conv-640)<<10);
            }
        }
        else {
            if (t_conv > 640) t_conv = 640;
        }

        if (IS_TANDY_ARCH) {
            /* reduce reported memory size for the Tandy (32k graphics memory
               at the end of the conventional 640k) */
            if (machine==MCH_TANDY && t_conv > 624) t_conv = 624;
        }

        /* allow user to further limit the available memory below 1MB */
        if (dos_conventional_limit != 0 && t_conv > dos_conventional_limit)
            t_conv = dos_conventional_limit;

        // TODO: Allow dosbox.conf to specify an option to add an EBDA (Extended BIOS Data Area)
        //       at the top of the DOS conventional limit, which we then reduce further to hold
        //       it. Most BIOSes past 1992 or so allocate an EBDA.

        /* if requested to emulate an ISA memory hole at 512KB, further limit the memory */
        if (isa_memory_hole_512kb && t_conv > 512) t_conv = 512;

        /* and then unmap RAM between t_conv and ulimit */
        if (t_conv < ulimit) {
            Bitu start = (t_conv+3)/4;  /* start = 1KB to page round up */
            Bitu end = ulimit/4;        /* end = 1KB to page round down */
            if (start < end) MEM_ResetPageHandler_Unmapped(start,end-start);
        }

        /* INT 4B. Now we can safely signal error instead of printing "Invalid interrupt 4B"
         * whenever we install Windows 95. Note that Windows 95 would call INT 4Bh because
         * that is where the Virtual DMA API lies in relation to EMM386.EXE */
        int4b_callback.Install(&INT4B_Handler,CB_IRET,"INT 4B");

        /* INT 14 Serial Ports */
        callback[3].Install(&INT14_Handler,CB_IRET_STI,"Int 14 COM-port");

        /* INT 15 Misc Calls */
        callback[4].Install(&INT15_Handler,CB_IRET,"Int 15 Bios");

        /* INT 17 Printer Routines */
        callback[5].Install(&INT17_Handler,CB_IRET_STI,"Int 17 Printer");

        /* INT 1A TIME and some other functions */
        callback[6].Install(&INT1A_Handler,CB_IRET_STI,"Int 1a Time");

        /* INT 1C System Timer tick called from INT 8 */
        callback[7].Install(&INT1C_Handler,CB_IRET,"Int 1c Timer");
        
        /* IRQ 8 RTC Handler */
        callback[8].Install(&INT70_Handler,CB_IRET,"Int 70 RTC");

        /* Irq 9 rerouted to irq 2 */
        callback[9].Install(NULL,CB_IRQ9,"irq 9 bios");

        // INT 19h: Boot function
        callback[10].Install(&INT19_Handler,CB_IRET,"int 19");

        // INT 76h: IDE IRQ 14
        // This is just a dummy IRQ handler to prevent crashes when
        // IDE emulation fires the IRQ and OS's like Win95 expect
        // the BIOS to handle the interrupt.
        // FIXME: Shouldn't the IRQ send an ACK to the PIC as well?!?
        callback[11].Install(&IRQ14_Dummy,CB_IRET_EOI_PIC2,"irq 14 ide");

        // INT 77h: IDE IRQ 15
        // This is just a dummy IRQ handler to prevent crashes when
        // IDE emulation fires the IRQ and OS's like Win95 expect
        // the BIOS to handle the interrupt.
        // FIXME: Shouldn't the IRQ send an ACK to the PIC as well?!?
        callback[12].Install(&IRQ15_Dummy,CB_IRET_EOI_PIC2,"irq 15 ide");

        // INT 0Eh: IDE IRQ 6
        callback[13].Install(&IRQ15_Dummy,CB_IRET_EOI_PIC1,"irq 6 floppy");

        // INT 18h: Enter BASIC
        // Non-IBM BIOS would display "NO ROM BASIC" here
        callback[15].Install(&INT18_Handler,CB_IRET,"int 18");

        init_vm86_fake_io();

        /* Irq 2-7 */
        call_irq07default=CALLBACK_Allocate();

        /* Irq 8-15 */
        call_irq815default=CALLBACK_Allocate();

        /* BIOS boot stages */
        cb_bios_post.Install(&cb_bios_post__func,CB_RETF,"BIOS POST");
        cb_bios_scan_video_bios.Install(&cb_bios_scan_video_bios__func,CB_RETF,"BIOS Scan Video BIOS");
        cb_bios_adapter_rom_scan.Install(&cb_bios_adapter_rom_scan__func,CB_RETF,"BIOS Adapter ROM scan");
        cb_bios_startup_screen.Install(&cb_bios_startup_screen__func,CB_RETF,"BIOS Startup screen");
        cb_bios_boot.Install(&cb_bios_boot__func,CB_RETF,"BIOS BOOT");
        cb_bios_bootfail.Install(&cb_bios_bootfail__func,CB_RETF,"BIOS BOOT FAIL");

        if (IS_PC98_ARCH)
            cb_pc98_rombasic.Install(&cb_pc98_entry__func,CB_RETF,"N88 ROM BASIC");

        // Compatible POST routine location: jump to the callback
        {
            Bitu wo_fence;

            Bitu wo = Real2Phys(BIOS_DEFAULT_RESET_LOCATION);
            wo_fence = wo + 64;

            // POST
            phys_writeb(wo+0x00,(Bit8u)0xFE);                       //GRP 4
            phys_writeb(wo+0x01,(Bit8u)0x38);                       //Extra Callback instruction
            phys_writew(wo+0x02,(Bit16u)cb_bios_post.Get_callback());           //The immediate word
            wo += 4;

            // video bios scan
            phys_writeb(wo+0x00,(Bit8u)0xFE);                       //GRP 4
            phys_writeb(wo+0x01,(Bit8u)0x38);                       //Extra Callback instruction
            phys_writew(wo+0x02,(Bit16u)cb_bios_scan_video_bios.Get_callback());        //The immediate word
            wo += 4;

            // adapter ROM scan
            phys_writeb(wo+0x00,(Bit8u)0xFE);                       //GRP 4
            phys_writeb(wo+0x01,(Bit8u)0x38);                       //Extra Callback instruction
            phys_writew(wo+0x02,(Bit16u)cb_bios_adapter_rom_scan.Get_callback());       //The immediate word
            wo += 4;

            // startup screen
            phys_writeb(wo+0x00,(Bit8u)0xFE);                       //GRP 4
            phys_writeb(wo+0x01,(Bit8u)0x38);                       //Extra Callback instruction
            phys_writew(wo+0x02,(Bit16u)cb_bios_startup_screen.Get_callback());     //The immediate word
            wo += 4;

            // user boot hook
            if (bios_user_boot_hook != 0) {
                phys_writeb(wo+0x00,0x9C);                          //PUSHF
                phys_writeb(wo+0x01,0x9A);                          //CALL FAR
                phys_writew(wo+0x02,0x0000);                        //seg:0
                phys_writew(wo+0x04,bios_user_boot_hook>>4);
                wo += 6;
            }

            // boot
            BIOS_boot_code_offset = wo;
            phys_writeb(wo+0x00,(Bit8u)0xFE);                       //GRP 4
            phys_writeb(wo+0x01,(Bit8u)0x38);                       //Extra Callback instruction
            phys_writew(wo+0x02,(Bit16u)cb_bios_boot.Get_callback());           //The immediate word
            wo += 4;

            // boot fail
            BIOS_bootfail_code_offset = wo;
            phys_writeb(wo+0x00,(Bit8u)0xFE);                       //GRP 4
            phys_writeb(wo+0x01,(Bit8u)0x38);                       //Extra Callback instruction
            phys_writew(wo+0x02,(Bit16u)cb_bios_bootfail.Get_callback());           //The immediate word
            wo += 4;

            /* fence */
            phys_writeb(wo++,0xEB);                             // JMP $-2
            phys_writeb(wo++,0xFE);

            if (wo > wo_fence) E_Exit("BIOS boot callback overrun");

            if (IS_PC98_ARCH) {
                /* Boot disks that run N88 basic, stopgap */
                PhysPt bo = 0xE8002; // E800:0002

                phys_writeb(bo+0x00,(Bit8u)0xFE);                       //GRP 4
                phys_writeb(bo+0x01,(Bit8u)0x38);                       //Extra Callback instruction
                phys_writew(bo+0x02,(Bit16u)cb_pc98_rombasic.Get_callback());           //The immediate word

                phys_writeb(bo+0x04,0xEB);                             // JMP $-2
                phys_writeb(bo+0x05,0xFE);
            }

            if (IS_PC98_ARCH && enable_pc98_copyright_string) {
                size_t i=0;

                for (;i < pc98_copyright_str.length();i++)
                    phys_writeb(0xE8000 + 0x0DD8 + (PhysPt)i,(Bit8u)pc98_copyright_str[i]);

                phys_writeb(0xE8000 + 0x0DD8 + (PhysPt)i,0);

                for (i=0;i < sizeof(pc98_epson_check_2);i++)
                    phys_writeb(0xF5200 + 0x018E + (PhysPt)i,(Bit8u)pc98_epson_check_2[i]);
            }
        }
    }
    ~BIOS(){
        /* snap the CPU back to real mode. this code thinks in terms of 16-bit real mode
         * and if allowed to do it's thing in a 32-bit guest OS like WinNT, will trigger
         * a page fault. */
        CPU_Snap_Back_To_Real_Mode();

        if (BOCHS_PORT_E9) {
            delete BOCHS_PORT_E9;
            BOCHS_PORT_E9=NULL;
        }
        if (ISAPNP_PNP_ADDRESS_PORT) {
            delete ISAPNP_PNP_ADDRESS_PORT;
            ISAPNP_PNP_ADDRESS_PORT=NULL;
        }
        if (ISAPNP_PNP_DATA_PORT) {
            delete ISAPNP_PNP_DATA_PORT;
            ISAPNP_PNP_DATA_PORT=NULL;
        }
        if (ISAPNP_PNP_READ_PORT) {
            delete ISAPNP_PNP_READ_PORT;
            ISAPNP_PNP_READ_PORT=NULL;
        }
        if (isapnpigdevice) {
            /* ISA PnP will auto-free it */
            isapnpigdevice=NULL;
        }

        if (dosbox_int_iocallout != IO_Callout_t_none) {
            IO_FreeCallout(dosbox_int_iocallout);
            dosbox_int_iocallout = IO_Callout_t_none;
        }

        /* abort DAC playing */
        if (tandy_sb.port) {
            IO_Write(tandy_sb.port+0xcu,0xd3u);
            IO_Write(tandy_sb.port+0xcu,0xd0u);
        }
        real_writeb(0x40,0xd4,0x00);
        if (tandy_DAC_callback[0]) {
            Bit32u orig_vector=real_readd(0x40,0xd6);
            if (orig_vector==tandy_DAC_callback[0]->Get_RealPointer()) {
                /* set IRQ vector to old value */
                Bit8u tandy_irq = 7;
                if (tandy_sb.port) tandy_irq = tandy_sb.irq;
                else if (tandy_dac.port) tandy_irq = tandy_dac.irq;
                Bit8u tandy_irq_vector = tandy_irq;
                if (tandy_irq_vector<8) tandy_irq_vector += 8;
                else tandy_irq_vector += (0x70-8);

                RealSetVec(tandy_irq_vector,real_readd(0x40,0xd6));
                real_writed(0x40,0xd6,0x00000000);
            }
            delete tandy_DAC_callback[0];
            delete tandy_DAC_callback[1];
            tandy_DAC_callback[0]=NULL;
            tandy_DAC_callback[1]=NULL;
        }

        /* encourage the callback objects to uninstall HERE while we're in real mode, NOT during the
         * destructor stage where we're back in protected mode */
        for (unsigned int i=0;i < 20;i++) callback[i].Uninstall();

        /* assume these were allocated */
        CALLBACK_DeAllocate(call_irq0);
        CALLBACK_DeAllocate(call_irq07default);
        CALLBACK_DeAllocate(call_irq815default);

        /* done */
        CPU_Snap_Back_Restore();
    }
};

void BIOS_Enter_Boot_Phase(void) {
    /* direct CS:IP right to the instruction that leads to the boot process */
    /* note that since it's a callback instruction it doesn't really matter
     * what CS:IP is as long as it points to the instruction */
    reg_eip = BIOS_boot_code_offset & 0xFUL;
    CPU_SetSegGeneral(cs, BIOS_boot_code_offset >> 4UL);
}

void BIOS_SetCOMPort(Bitu port, Bit16u baseaddr) {
    switch(port) {
    case 0:
        mem_writew(BIOS_BASE_ADDRESS_COM1,baseaddr);
        mem_writeb(BIOS_COM1_TIMEOUT, 10); // FIXME: Right??
        break;
    case 1:
        mem_writew(BIOS_BASE_ADDRESS_COM2,baseaddr);
        mem_writeb(BIOS_COM2_TIMEOUT, 10); // FIXME: Right??
        break;
    case 2:
        mem_writew(BIOS_BASE_ADDRESS_COM3,baseaddr);
        mem_writeb(BIOS_COM3_TIMEOUT, 10); // FIXME: Right??
        break;
    case 3:
        mem_writew(BIOS_BASE_ADDRESS_COM4,baseaddr);
        mem_writeb(BIOS_COM4_TIMEOUT, 10); // FIXME: Right??
        break;
    }
}

void BIOS_SetLPTPort(Bitu port, Bit16u baseaddr) {
    switch(port) {
    case 0:
        mem_writew(BIOS_ADDRESS_LPT1,baseaddr);
        mem_writeb(BIOS_LPT1_TIMEOUT, 10);
        break;
    case 1:
        mem_writew(BIOS_ADDRESS_LPT2,baseaddr);
        mem_writeb(BIOS_LPT2_TIMEOUT, 10);
        break;
    case 2:
        mem_writew(BIOS_ADDRESS_LPT3,baseaddr);
        mem_writeb(BIOS_LPT3_TIMEOUT, 10);
        break;
    }
}

void BIOS_PnP_ComPortRegister(Bitu port,Bitu irq) {
    /* add to PnP BIOS */
    if (ISAPNPBIOS) {
        unsigned char tmp[256];
        unsigned int i;

        /* register serial ports */
        const unsigned char h1[9] = {
            ISAPNP_SYSDEV_HEADER(
                ISAPNP_ID('P','N','P',0x0,0x5,0x0,0x1), /* PNP0501 16550A-compatible COM port */
                ISAPNP_TYPE(0x07,0x00,0x02),        /* type: RS-232 communcations device, 16550-compatible */
                0x0001 | 0x0002)
        };

        i = 0;
        memcpy(tmp+i,h1,9); i += 9;         /* can't disable, can't configure */
        /*----------allocated--------*/
        tmp[i+0] = (8 << 3) | 7;            /* IO resource */
        tmp[i+1] = 0x01;                /* 16-bit decode */
        host_writew(tmp+i+2,port);          /* min */
        host_writew(tmp+i+4,port);          /* max */
        tmp[i+6] = 0x10;                /* align */
        tmp[i+7] = 0x08;                /* length */
        i += 7+1;

        if (irq > 0) {
            tmp[i+0] = (4 << 3) | 3;            /* IRQ resource */
            host_writew(tmp+i+1,1 << irq);
            tmp[i+3] = 0x09;                /* HTL=1 LTL=1 */
            i += 3+1;
        }

        tmp[i+0] = 0x79;                /* END TAG */
        tmp[i+1] = 0x00;
        i += 2;
        /*-------------possible-----------*/
        tmp[i+0] = 0x79;                /* END TAG */
        tmp[i+1] = 0x00;
        i += 2;
        /*-------------compatible---------*/
        tmp[i+0] = 0x79;                /* END TAG */
        tmp[i+1] = 0x00;
        i += 2;

        if (!ISAPNP_RegisterSysDev(tmp,i)) {
            //LOG_MSG("ISAPNP register failed\n");
        }
    }
}

static BIOS* test = NULL;

void BIOS_Destroy(Section* /*sec*/){
    ROMBIOS_DumpMemory();
    ISA_PNP_FreeAllDevs();
    if (test != NULL) {
        delete test;
        test = NULL;
    }
}

void BIOS_OnPowerOn(Section* sec) {
    (void)sec;//UNUSED
    if (test) delete test;
    test = new BIOS(control->GetSection("joystick"));
}

void swapInNextDisk(bool pressed);
void swapInNextCD(bool pressed);

void INT10_OnResetComplete();
void CALLBACK_DeAllocate(Bitu in);

void MOUSE_Unsetup_DOS(void);
void MOUSE_Unsetup_BIOS(void);

void BIOS_OnResetComplete(Section *x) {
    (void)x;//UNUSED
    INT10_OnResetComplete();

    if (IS_PC98_ARCH) {
        void PC98_BIOS_Bank_Switch_Reset(void);
        PC98_BIOS_Bank_Switch_Reset();
    }

    if (biosConfigSeg != 0u) {
        ROMBIOS_FreeMemory((Bitu)(biosConfigSeg << 4u)); /* remember it was alloc'd paragraph aligned, then saved >> 4 */
        biosConfigSeg = 0u;
    }

    call_pnp_rp = 0;
    if (call_pnp_r != ~0UL) {
        CALLBACK_DeAllocate(call_pnp_r);
        call_pnp_r = ~0UL;
    }

    call_pnp_pp = 0;
    if (call_pnp_p != ~0UL) {
        CALLBACK_DeAllocate(call_pnp_p);
        call_pnp_p = ~0UL;
    }

    MOUSE_Unsetup_DOS();
    MOUSE_Unsetup_BIOS();

    ISA_PNP_FreeAllSysNodeDevs();
}

void BIOS_Init() {
    DOSBoxMenu::item *item;

    LOG(LOG_MISC,LOG_DEBUG)("Initializing BIOS");

    /* make sure the array is zeroed */
    ISAPNP_SysDevNodeCount = 0;
    ISAPNP_SysDevNodeLargest = 0;
    for (int i=0;i < MAX_ISA_PNP_SYSDEVNODES;i++) ISAPNP_SysDevNodes[i] = NULL;

    /* make sure CD swap and floppy swap mapper events are available */
    MAPPER_AddHandler(swapInNextDisk,MK_d,MMODHOST|MMOD1,"swapimg","SwapFloppy",&item); /* Originally "Swap Image" but this version does not swap CDs */
    item->set_text("Swap floppy");

    MAPPER_AddHandler(swapInNextCD,MK_c,MMODHOST|MMOD1,"swapcd","SwapCD",&item); /* Variant of "Swap Image" for CDs */
    item->set_text("Swap CD");

    /* NTS: VM_EVENT_BIOS_INIT this callback must be first. */
    AddExitFunction(AddExitFunctionFuncPair(BIOS_Destroy),false);
    AddVMEventFunction(VM_EVENT_POWERON,AddVMEventFunctionFuncPair(BIOS_OnPowerOn));
    AddVMEventFunction(VM_EVENT_RESET_END,AddVMEventFunctionFuncPair(BIOS_OnResetComplete));
}

void write_ID_version_string() {
    Bitu str_id_at,str_ver_at;
    size_t str_id_len,str_ver_len;

    /* NTS: We can't move the version and ID strings, it causes programs like MSD.EXE to lose
     *      track of the "IBM compatible blahblahblah" string. Which means that apparently
     *      programs looking for this information have the address hardcoded ALTHOUGH
     *      experiments show you can move the version string around so long as it's
     *      +1 from a paragraph boundary */
    /* TODO: *DO* allow dynamic relocation however if the dosbox.conf indicates that the user
     *       is not interested in IBM BIOS compatability. Also, it would be really cool if
     *       dosbox.conf could override these strings and the user could enter custom BIOS
     *       version and ID strings. Heh heh heh.. :) */
    str_id_at = 0xFE00E;
    str_ver_at = 0xFE061;
    str_id_len = strlen(bios_type_string)+1;
    str_ver_len = strlen(bios_version_string)+1;
    if (!IS_PC98_ARCH) {
        /* need to mark these strings off-limits so dynamic allocation does not overwrite them */
        ROMBIOS_GetMemory((Bitu)str_id_len+1,"BIOS ID string",1,str_id_at);
        ROMBIOS_GetMemory((Bitu)str_ver_len+1,"BIOS version string",1,str_ver_at);
    }
    if (str_id_at != 0) {
        for (size_t i=0;i < str_id_len;i++) phys_writeb(str_id_at+(PhysPt)i,(Bit8u)bios_type_string[i]);
    }
    if (str_ver_at != 0) {
        for (size_t i=0;i < str_ver_len;i++) phys_writeb(str_ver_at+(PhysPt)i,(Bit8u)bios_version_string[i]);
    }
}

extern Bit8u int10_font_08[256 * 8];

/* NTS: Do not use callbacks! This function is called before CALLBACK_Init() */
void ROMBIOS_Init() {
    Section_prop * section=static_cast<Section_prop *>(control->GetSection("dosbox"));
    Bitu oi;

    // log
    LOG(LOG_MISC,LOG_DEBUG)("Initializing ROM BIOS");

    oi = (Bitu)section->Get_int("rom bios minimum size"); /* in KB */
    oi = (oi + 3u) & ~3u; /* round to 4KB page */
    if (oi > 128u) oi = 128u;
    if (oi == 0u) {
        if (IS_PC98_ARCH)
            oi = 96u; // BIOS standard range is E8000-FFFFF
        else
            oi = 64u;
    }
    if (oi < 8) oi = 8; /* because of some of DOSBox's fixed ROM structures we can only go down to 8KB */
    rombios_minimum_size = (oi << 10); /* convert to minimum, using size coming downward from 1MB */

    oi = (Bitu)section->Get_int("rom bios allocation max"); /* in KB */
    oi = (oi + 3u) & ~3u; /* round to 4KB page */
    if (oi > 128u) oi = 128u;
    if (oi == 0u) {
        if (IS_PC98_ARCH)
            oi = 96u;
        else
            oi = 64u;
    }
    if (oi < 8u) oi = 8u; /* because of some of DOSBox's fixed ROM structures we can only go down to 8KB */
    oi <<= 10u;
    if (oi < rombios_minimum_size) oi = rombios_minimum_size;
    rombios_minimum_location = 0x100000ul - oi; /* convert to minimum, using size coming downward from 1MB */

    LOG(LOG_BIOS,LOG_DEBUG)("ROM BIOS range: 0x%05X-0xFFFFF",(int)rombios_minimum_location);
    LOG(LOG_BIOS,LOG_DEBUG)("ROM BIOS range according to minimum size: 0x%05X-0xFFFFF",(int)(0x100000 - rombios_minimum_size));

    if (IS_PC98_ARCH && rombios_minimum_location > 0xE8000)
        LOG(LOG_BIOS,LOG_DEBUG)("Caution: Minimum ROM base higher than E8000 will prevent use of actual PC-98 BIOS image or N88 BASIC");

    if (!MEM_map_ROM_physmem(rombios_minimum_location,0xFFFFF)) E_Exit("Unable to map ROM region as ROM");

    /* and the BIOS alias at the top of memory (TODO: what about 486/Pentium emulation where the BIOS at the 4GB top is different
     * from the BIOS at the legacy 1MB boundary because of shadowing and/or decompressing from ROM at boot? */
    {
        uint64_t top = (uint64_t)1UL << (uint64_t)MEM_get_address_bits();
        if (top >= ((uint64_t)1UL << (uint64_t)21UL)) { /* 2MB or more */
            unsigned long alias_base,alias_end;

            alias_base = (unsigned long)top + (unsigned long)rombios_minimum_location - (unsigned long)0x100000UL;
            alias_end = (unsigned long)top - (unsigned long)1UL;

            LOG(LOG_BIOS,LOG_DEBUG)("ROM BIOS also mapping alias to 0x%08lx-0x%08lx",alias_base,alias_end);
            if (!MEM_map_ROM_alias_physmem(alias_base,alias_end)) {
                void MEM_cut_RAM_up_to(Bitu addr);

                /* it's possible if memory aliasing is set that memsize is too large to make room.
                 * let memory emulation know where the ROM BIOS starts so it can unmap the RAM pages,
                 * reduce the memory reported to the OS, and try again... */
                LOG(LOG_BIOS,LOG_DEBUG)("No room for ROM BIOS alias, reducing reported memory and unmapping RAM pages to make room");
                MEM_cut_RAM_up_to(alias_base);

                if (!MEM_map_ROM_alias_physmem(alias_base,alias_end))
                    E_Exit("Unable to map ROM region as ROM alias");
            }
        }
    }

    /* set up allocation */
    rombios_alloc.name = "ROM BIOS";
    rombios_alloc.topDownAlloc = true;
    rombios_alloc.initSetRange(rombios_minimum_location,0xFFFF0 - 1);

    write_ID_version_string();

    if (IS_PC98_ARCH && enable_pc98_copyright_string) { // PC-98 BIOSes have a copyright string at E800:0DD8
        if (ROMBIOS_GetMemory(pc98_copyright_str.length()+1,"PC-98 copyright string",1,0xE8000 + 0x0DD8) == 0)
            LOG_MSG("WARNING: Was not able to mark off E800:0DD8 off-limits for PC-98 copyright string");
        if (ROMBIOS_GetMemory(sizeof(pc98_epson_check_2),"PC-98 unknown data / Epson check",1,0xF5200 + 0x018E) == 0)
            LOG_MSG("WARNING: Was not able to mark off E800:0DD8 off-limits for PC-98 copyright string");
    }
 
    /* some structures when enabled are fixed no matter what */
    if (rom_bios_8x8_cga_font && !IS_PC98_ARCH) {
        /* line 139, int10_memory.cpp: the 8x8 font at 0xF000:FA6E, first 128 chars.
         * allocate this NOW before other things get in the way */
        if (ROMBIOS_GetMemory(128*8,"BIOS 8x8 font (first 128 chars)",1,0xFFA6E) == 0) {
            LOG_MSG("WARNING: Was not able to mark off 0xFFA6E off-limits for 8x8 font");
        }
    }

    /* PC-98 BIOS vectors appear to reside at segment 0xFD80. This is so common some games
     * use it (through INT 1Dh) to detect whether they are running on PC-98 or not (issue #927).
     *
     * Note that INT 1Dh is one of the few BIOS interrupts not intercepted by PC-98 MS-DOS */
    if (IS_PC98_ARCH) {
        if (ROMBIOS_GetMemory(128,"PC-98 INT vector stub segment 0xFD80",1,0xFD800) == 0) {
            LOG_MSG("WARNING: Was not able to mark off 0xFD800 off-limits for PC-98 int vector stubs");
        }
    }

    /* PC-98 BIOSes have a LIO interface at segment F990 with graphic subroutines for Microsoft BASIC */
    if (IS_PC98_ARCH) {
        if (ROMBIOS_GetMemory(256,"PC-98 LIO graphic ROM BIOS library",1,0xF9900) == 0) {
            LOG_MSG("WARNING: Was not able to mark off 0xF9900 off-limits for PC-98 LIO graphics library");
        }
    }

    /* install the font */
    if (rom_bios_8x8_cga_font) {
        for (Bitu i=0;i<128*8;i++) {
            phys_writeb(PhysMake(0xf000,0xfa6e)+i,int10_font_08[i]);
        }
    }

    /* we allow dosbox.conf to specify a binary blob to load into ROM BIOS and execute after reset.
     * we allow this for both hacker curiosity and automated CPU testing. */
    {
        std::string path = section->Get_string("call binary on reset");
        struct stat st;

        if (!path.empty() && stat(path.c_str(),&st) == 0 && S_ISREG(st.st_mode) && st.st_size <= (off_t)(128u*1024u)) {
            Bitu base = ROMBIOS_GetMemory((Bitu)st.st_size,"User reset vector binary",16u/*page align*/,0u);

            if (base != 0) {
                FILE *fp = fopen(path.c_str(),"rb");

                if (fp != NULL) {
                    /* NTS: Make sure memory base != NULL, and that it fits within 1MB.
                     *      memory code allocates a minimum 1MB of memory even if
                     *      guest memory is less than 1MB because ROM BIOS emulation
                     *      depends on it. */
                    assert(GetMemBase() != NULL);
                    assert((base+(Bitu)st.st_size) <= 0x100000ul);
                    size_t readResult = fread(GetMemBase()+base,(size_t)st.st_size,1u,fp);
                    fclose(fp);
                    if (readResult != 1) {
                        LOG(LOG_IO, LOG_ERROR) ("Reading error in ROMBIOS_Init\n");
                        return;
                    }

                    LOG_MSG("User reset vector binary '%s' loaded at 0x%lx",path.c_str(),(unsigned long)base);
                    bios_user_reset_vector_blob = base;
                }
                else {
                    LOG_MSG("WARNING: Unable to open file to load user reset vector binary '%s' into ROM BIOS memory",path.c_str());
                }
            }
            else {
                LOG_MSG("WARNING: Unable to load user reset vector binary '%s' into ROM BIOS memory",path.c_str());
            }
        }
    }

    /* we allow dosbox.conf to specify a binary blob to load into ROM BIOS and execute just before boot.
     * we allow this for both hacker curiosity and automated CPU testing. */
    {
        std::string path = section->Get_string("call binary on boot");
        struct stat st;

        if (!path.empty() && stat(path.c_str(),&st) == 0 && S_ISREG(st.st_mode) && st.st_size <= (off_t)(128u*1024u)) {
            Bitu base = ROMBIOS_GetMemory((Bitu)st.st_size,"User boot hook binary",16u/*page align*/,0u);

            if (base != 0) {
                FILE *fp = fopen(path.c_str(),"rb");

                if (fp != NULL) {
                    /* NTS: Make sure memory base != NULL, and that it fits within 1MB.
                     *      memory code allocates a minimum 1MB of memory even if
                     *      guest memory is less than 1MB because ROM BIOS emulation
                     *      depends on it. */
                    assert(GetMemBase() != NULL);
                    assert((base+(Bitu)st.st_size) <= 0x100000ul);
                    size_t readResult = fread(GetMemBase()+base,(size_t)st.st_size,1u,fp);
                    fclose(fp);
                    if (readResult != 1) {
                        LOG(LOG_IO, LOG_ERROR) ("Reading error in ROMBIOS_Init\n");
                        return;
                    }

                    LOG_MSG("User boot hook binary '%s' loaded at 0x%lx",path.c_str(),(unsigned long)base);
                    bios_user_boot_hook = base;
                }
                else {
                    LOG_MSG("WARNING: Unable to open file to load user boot hook binary '%s' into ROM BIOS memory",path.c_str());
                }
            }
            else {
                LOG_MSG("WARNING: Unable to load user boot hook binary '%s' into ROM BIOS memory",path.c_str());
            }
        }
    }
}

void UpdateKeyWithLed(int nVirtKey, int flagAct, int flagLed);

void BIOS_SynchronizeNumLock()
{
#if defined(WIN32)
        UpdateKeyWithLed(VK_NUMLOCK, BIOS_KEYBOARD_FLAGS1_NUMLOCK_ACTIVE, BIOS_KEYBOARD_LEDS_NUM_LOCK);
#endif
}

void BIOS_SynchronizeCapsLock()
{
#if defined(WIN32)
        UpdateKeyWithLed(VK_CAPITAL, BIOS_KEYBOARD_FLAGS1_CAPS_LOCK_ACTIVE, BIOS_KEYBOARD_LEDS_CAPS_LOCK);
#endif
}

void BIOS_SynchronizeScrollLock()
{
#if defined(WIN32)
        UpdateKeyWithLed(VK_SCROLL, BIOS_KEYBOARD_FLAGS1_SCROLL_LOCK_ACTIVE, BIOS_KEYBOARD_LEDS_SCROLL_LOCK);
#endif
}

void UpdateKeyWithLed(int nVirtKey, int flagAct, int flagLed)
{
#if defined(WIN32)

        const auto state = GetKeyState(nVirtKey);

        const auto flags1 = BIOS_KEYBOARD_FLAGS1;
        const auto flags2 = BIOS_KEYBOARD_LEDS;

        auto flag1 = mem_readb(flags1);
        auto flag2 = mem_readb(flags2);

        if (state & 1)
        {
                flag1 |= flagAct;
                flag2 |= flagLed;
        }
        else
        {
                flag1 &= ~flagAct;
                flag2 &= ~flagLed;
        }

        mem_writeb(flags1, flag1);
        mem_writeb(flags2, flag2);

#else

    (void)nVirtKey;
    (void)flagAct;
    (void)flagLed;

#endif
}