src/hardware/tandy_sound.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.
 */

/* 
        Based of sn76496.c of the M.A.M.E. project
*/

#include "dosbox.h"
#include "inout.h"
#include "mixer.h"
#include "mem.h"
#include "setup.h"
#include "pic.h"
#include "dma.h"
#include "control.h"
#include "hardware.h"
#include <cstring>
#include <math.h>
#include "mame/emu.h"
#include "mame/sn76496.h"


#define SOUND_CLOCK (14318180 / 4)

#define TDAC_DMA_BUFSIZE 1024

static struct {
        MixerChannel * chan;
        bool enabled;
        Bitu last_write;
        struct {
                MixerChannel * chan;
                bool enabled;
                struct {
                        Bitu base;
                        Bit8u irq,dma;
                } hw;
                struct {
                        Bitu rate;
                        Bit8u buf[TDAC_DMA_BUFSIZE];
                        Bit8u last_sample;
                        DmaChannel * chan;
                        bool transfer_done;
                } dma;
                Bit8u mode,control;
                Bit16u frequency;
                Bit8u amplitude;
                bool irq_activated;
        } dac;
} tandy;

static sn76496_device device_sn76496(machine_config(), 0, 0, SOUND_CLOCK );
static ncr8496_device device_ncr8496(machine_config(), 0, 0, SOUND_CLOCK);

static sn76496_base_device* activeDevice = &device_ncr8496;
#define device (*activeDevice)

static void SN76496Write(Bitu /*port*/,Bitu data,Bitu /*iolen*/) {
        tandy.last_write=PIC_Ticks;
        if (!tandy.enabled) {
                tandy.chan->Enable(true);
                tandy.enabled=true;
        }

        // assume state change, always.
        // this hack allows sample accurate rendering without enabling sample accurate mode in the mixer.
        tandy.chan->FillUp();

        device.write((uint8_t)data);

//      LOG_MSG("3voice write %X at time %7.3f",data,PIC_FullIndex());
}

static void SN76496Update(Bitu length) {
        //Disable the channel if it's been quiet for a while
        if ((tandy.last_write+5000)<PIC_Ticks) {
                tandy.enabled=false;
                tandy.chan->Enable(false);
                return;
        }
        const Bitu MAX_SAMPLES = 2048;
        if (length > MAX_SAMPLES)
                return;
        Bit16s buffer[MAX_SAMPLES];
        Bit16s* outputs = buffer;

        device_sound_interface::sound_stream stream;
        static_cast<device_sound_interface&>(device).sound_stream_update(stream, 0, &outputs, (int)length);
        tandy.chan->AddSamples_m16(length, buffer);
}

bool TS_Get_Address(Bitu& tsaddr, Bitu& tsirq, Bitu& tsdma) {
        tsaddr=0;
        tsirq =0;
        tsdma =0;
        if (tandy.dac.enabled) {
                tsaddr=tandy.dac.hw.base;
                tsirq =tandy.dac.hw.irq;
                tsdma =tandy.dac.hw.dma;
                return true;
        }
        return false;
}


static void TandyDAC_DMA_CallBack(DmaChannel * /*chan*/, DMAEvent event) {
        if (event == DMA_REACHED_TC) {
                tandy.dac.dma.transfer_done=true;
                PIC_ActivateIRQ(tandy.dac.hw.irq);
        }
}

static void TandyDACModeChanged(void) {
        switch (tandy.dac.mode&3) {
        case 0:
                // joystick mode
                break;
        case 1:
                break;
        case 2:
                // recording
                break;
        case 3:
                // playback
                tandy.dac.chan->FillUp();
                if (tandy.dac.frequency!=0) {
                        float freq=3579545.0f/((float)tandy.dac.frequency);
                        tandy.dac.chan->SetFreq((Bitu)freq);
                        float vol=((float)tandy.dac.amplitude)/7.0f;
                        tandy.dac.chan->SetVolume(vol,vol);
                        if ((tandy.dac.mode&0x0c)==0x0c) {
                                tandy.dac.dma.transfer_done=false;
                                tandy.dac.dma.chan=GetDMAChannel(tandy.dac.hw.dma);
                                if (tandy.dac.dma.chan) {
                                        tandy.dac.dma.chan->Register_Callback(TandyDAC_DMA_CallBack);
                                        tandy.dac.chan->Enable(true);
//                                      LOG_MSG("Tandy DAC: playback started with freqency %f, volume %f",freq,vol);
                                }
                        }
                }
                break;
        }
}

static void TandyDACDMAEnabled(void) {
        TandyDACModeChanged();
}

static void TandyDACDMADisabled(void) {
}

static void TandyDACWrite(Bitu port,Bitu data,Bitu /*iolen*/) {
        switch (port) {
        case 0xc4: {
                Bitu oldmode = tandy.dac.mode;
                tandy.dac.mode = (Bit8u)(data&0xff);
                if ((data&3)!=(oldmode&3)) {
                        TandyDACModeChanged();
                }
                if (((data&0x0c)==0x0c) && ((oldmode&0x0c)!=0x0c)) {
                        TandyDACDMAEnabled();
                } else if (((data&0x0c)!=0x0c) && ((oldmode&0x0c)==0x0c)) {
                        TandyDACDMADisabled();
                }
                }
                break;
        case 0xc5:
                switch (tandy.dac.mode&3) {
                case 0:
                        // joystick mode
                        break;
                case 1:
                        tandy.dac.control = (Bit8u)(data&0xff);
                        break;
                case 2:
                        break;
                case 3:
                        // direct output
                        break;
                }
                break;
        case 0xc6:
                tandy.dac.frequency = (tandy.dac.frequency & 0xf00) | (Bit8u)(data & 0xff);
                switch (tandy.dac.mode&3) {
                case 0:
                        // joystick mode
                        break;
                case 1:
                case 2:
                case 3:
                        TandyDACModeChanged();
                        break;
                }
                break;
        case 0xc7:
                tandy.dac.frequency = (tandy.dac.frequency & 0x00ff) | (((Bit8u)(data & 0xf)) << 8);
                tandy.dac.amplitude = (Bit8u)(data>>5);
                switch (tandy.dac.mode&3) {
                case 0:
                        // joystick mode
                        break;
                case 1:
                case 2:
                case 3:
                        TandyDACModeChanged();
                        break;
                }
                break;
        }
}

static Bitu TandyDACRead(Bitu port,Bitu /*iolen*/) {
        switch (port) {
        case 0xc4:
                return (tandy.dac.mode&0x77) | (tandy.dac.irq_activated ? 0x08 : 0x00);
        case 0xc6:
                return (Bit8u)(tandy.dac.frequency&0xff);
        case 0xc7:
                return (Bit8u)(((tandy.dac.frequency>>8)&0xf) | (tandy.dac.amplitude<<5));
        }
        LOG_MSG("Tandy DAC: Read from unknown %X", (unsigned int)port);
        return 0xff;
}

static void TandyDACGenerateDMASound(Bitu length) {
        if (length) {
                Bitu read = tandy.dac.dma.chan->Read(length,tandy.dac.dma.buf);
                if (read > 0) {
                        tandy.dac.chan->AddSamples_m8(read,tandy.dac.dma.buf);
                        tandy.dac.dma.last_sample = tandy.dac.dma.buf[read - 1u];
                }

                /* repeat the last sample to fill output if not enough */
                if (read < length) {
                        for (Bitu ct=read; ct < length; ct++) {
                                tandy.dac.chan->AddSamples_m8(1,&tandy.dac.dma.last_sample);
                        }
                }
        }
}

static void TandyDACUpdate(Bitu length) {
        if (tandy.dac.enabled && ((tandy.dac.mode&0x0c)==0x0c)) {
                if (!tandy.dac.dma.transfer_done) {
                        Bitu len = length;
                        TandyDACGenerateDMASound(len);
                } else {
                        for (Bitu ct=0; ct < length; ct++) {
                                tandy.dac.chan->AddSamples_m8(1,&tandy.dac.dma.last_sample);
                        }
                }
                /* even if the DAC is disabled hold the last sample and SLOWLY restore DC.
                 * jumping to silence quickly here causes loud annoying pops in Prince of Persia
                 * when sound effects play. Prince of Persia seems to emit some very non-zero DC
                 * value (like 0x08) when not playing sound effects, so this is needed to
                 * recover from that without pops. This behavior also seems to match DAC behavior
                 * with Prince of Persia according to real Tandy 1000 TL/3 hardware, complete
                 * with the 8-bit DAC stepping noise on return to zero. In any case, this
                 * modification makes the Tandy DAC sound effects in Prince of Persia much
                 * more enjoyable to listen to and match the apparent sound of real hardware. */
                /* NTS: This doesn't quite make the DAC step noise heard on real hardware, but
                 *      it's good enough for now. */
        } else if (tandy.dac.dma.last_sample != 128) {
                for (Bitu ct=0; ct < length; ct++) {
                        tandy.dac.chan->AddSamples_m8(1,&tandy.dac.dma.last_sample);
                        if (tandy.dac.dma.last_sample != 128)
                                tandy.dac.dma.last_sample = (Bit8u)(((((int)tandy.dac.dma.last_sample - 128) * 63) / 64) + 128);
                }
        } else {
                tandy.dac.chan->AddSilence();
        }
}

Bit8u BIOS_tandy_D4_flag = 0;

class TANDYSOUND: public Module_base {
private:
        IO_WriteHandleObject WriteHandler[4];
        IO_ReadHandleObject ReadHandler[4];
        MixerObject MixerChan;
        MixerObject MixerChanDAC;
public:
        TANDYSOUND(Section* configuration):Module_base(configuration){
                Section_prop * section=static_cast<Section_prop *>(configuration);

                bool enable_hw_tandy_dac=true;
                Bitu sbport, sbirq, sbdma;
                if (SB_Get_Address(sbport, sbirq, sbdma)) {
                        enable_hw_tandy_dac=false;
                }

                BIOS_tandy_D4_flag = 0;

                //Select the correct tandy chip implementation
                if (machine == MCH_PCJR) activeDevice = &device_sn76496;
                else activeDevice = &device_ncr8496;

                if (IS_TANDY_ARCH) {
                        /* enable tandy sound if tandy=true/auto */
                        if ((strcmp(section->Get_string("tandy"),"true")!=0) &&
                                (strcmp(section->Get_string("tandy"),"on")!=0) &&
                                (strcmp(section->Get_string("tandy"),"auto")!=0)) return;
                } else {
                        /* only enable tandy sound if tandy=true */
                        if ((strcmp(section->Get_string("tandy"),"true")!=0) &&
                                (strcmp(section->Get_string("tandy"),"on")!=0)) return;

                        if (enable_hw_tandy_dac) {
                                WriteHandler[2].Install(0x1e0,SN76496Write,IO_MB,2);
                                WriteHandler[3].Install(0x1e4,TandyDACWrite,IO_MB,4);
//                              ReadHandler[3].Install(0x1e4,TandyDACRead,IO_MB,4);
                        }
                }

                /* ports from second DMA controller conflict with tandy ports at 0xC0.
                 * Furthermore, the default I/O handlers after de-registration are needed
                 * to ensure the SN76496 is writeable at port 0xC0 whether you're doing
                 * normal 8-bit I/O or your a weirdo like Prince of Persia using 16-bit
                 * I/O to write frequency values. (bugfix for Tandy mode of Prince of
                 * Persia). */
                CloseSecondDMAController();

                Bit32u sample_rate = section->Get_int("tandyrate");
                tandy.chan=MixerChan.Install(&SN76496Update,sample_rate,"TANDY");

                WriteHandler[0].Install(0xc0,SN76496Write,IO_MB,2);

                if (enable_hw_tandy_dac) {
                        // enable low-level Tandy DAC emulation
                        WriteHandler[1].Install(0xc4,TandyDACWrite,IO_MB,4);
                        ReadHandler[1].Install(0xc4,TandyDACRead,IO_MB,4);

                        tandy.dac.enabled=true;
                        tandy.dac.chan=MixerChanDAC.Install(&TandyDACUpdate,sample_rate,"TANDYDAC");
                        tandy.dac.chan->SetLowpassFreq(6000);
                        tandy.dac.chan->SetSlewFreq(22050);

                        tandy.dac.hw.base=0xc4;
                        tandy.dac.hw.irq =7;
                        tandy.dac.hw.dma =1;
                } else {
                        tandy.dac.enabled=false;
                        tandy.dac.hw.base=0;
                        tandy.dac.hw.irq =0;
                        tandy.dac.hw.dma =0;
                }

                tandy.dac.control=0;
                tandy.dac.mode   =0;
                tandy.dac.irq_activated=false;
                tandy.dac.frequency=0;
                tandy.dac.amplitude=0;
                tandy.dac.dma.last_sample=128;


                tandy.enabled=false;
                BIOS_tandy_D4_flag = 0xFF;

                ((device_t&)device).device_start();
                device.convert_samplerate(sample_rate);

        }
        ~TANDYSOUND(){ }
};



static TANDYSOUND* test = NULL;

void TANDYSOUND_ShutDown(Section* /*sec*/) {
    if (test) {
        delete test;
        test = NULL;
    }
}

void TANDYSOUND_OnReset(Section* sec) {
    (void)sec;//UNUSED
        if (test == NULL && !IS_PC98_ARCH) {
                LOG(LOG_MISC,LOG_DEBUG)("Allocating Tandy speaker emulation");
                test = new TANDYSOUND(control->GetSection("speaker"));
        }
}

void TANDYSOUND_Init() {
        LOG(LOG_MISC,LOG_DEBUG)("Initializing Tandy voice emulation");

        AddExitFunction(AddExitFunctionFuncPair(TANDYSOUND_ShutDown),true);
        AddVMEventFunction(VM_EVENT_RESET,AddVMEventFunctionFuncPair(TANDYSOUND_OnReset));
}

// save state support
void *TandyDAC_DMA_CallBack_Func = (void*)((uintptr_t)TandyDAC_DMA_CallBack);

void POD_Save_Tandy_Sound( std::ostream& stream )
{
        const char pod_name[32] = "Tandy";

        if( stream.fail() ) return;
        if( !test ) return;
        if( !tandy.chan ) return;


        WRITE_POD( &pod_name, pod_name );

        //*******************************************
        //*******************************************
        //*******************************************

        Bit8u dma_idx;


        dma_idx = 0xff;
        for( int lcv=0; lcv<8; lcv++ ) {
                if( tandy.dac.dma.chan == GetDMAChannel(lcv) ) { dma_idx = lcv; break; }
        }

        // *******************************************
        // *******************************************
        // *******************************************

        // - near-pure data
        WRITE_POD( &tandy, tandy );

        // - reloc ptr
        WRITE_POD( &dma_idx, dma_idx );

        // *******************************************
        // *******************************************
        // *******************************************

    activeDevice->SaveState(stream);

        tandy.chan->SaveState(stream);
        tandy.dac.chan->SaveState(stream);
}

void POD_Load_Tandy_Sound( std::istream& stream )
{
        char pod_name[32] = {0};

        if( stream.fail() ) return;
        if( !test ) return;
        if( !tandy.chan ) return;


        // error checking
        READ_POD( &pod_name, pod_name );
        if( strcmp( pod_name, "Tandy" ) ) {
                stream.clear( std::istream::failbit | std::istream::badbit );
                return;
        }

        //************************************************
        //************************************************
        //************************************************

        Bit8u dma_idx;
        MixerChannel *chan_old, *dac_chan_old;

        // - save static ptrs
        chan_old = tandy.chan;
        dac_chan_old = tandy.dac.chan;

        // *******************************************
        // *******************************************
        // *******************************************

        // - near-pure data
        READ_POD( &tandy, tandy );

        // - reloc ptr
        READ_POD( &dma_idx, dma_idx );

        // *******************************************
        // *******************************************
        // *******************************************
        tandy.dac.dma.chan = NULL;
        if( dma_idx != 0xff ) tandy.dac.dma.chan = GetDMAChannel(dma_idx);

        // *******************************************
        // *******************************************
        // *******************************************

        // - restore static ptrs
        tandy.chan = chan_old;
        tandy.dac.chan = dac_chan_old;
    activeDevice->LoadState(stream);

        tandy.chan->LoadState(stream);
        tandy.dac.chan->LoadState(stream);
}