src/hardware/snd_pc98/sound/adpcmc.c

#include    "np2glue.h"
//#include      "compiler.h"
#include        "sound.h"
#include        "opngen.h"
#include        "adpcm.h"


        ADPCMCFG        adpcmcfg;

void adpcm_initialize(UINT rate) {

        adpcmcfg.rate = rate;
}

void adpcm_setvol(UINT vol) {

        adpcmcfg.vol = vol;
}

void adpcm_reset(ADPCM ad) {

        ZeroMemory(ad, sizeof(_ADPCM));
        ad->mask = 0;                                   // (UINT8)~0x1c;
        ad->delta = 127;
        STOREINTELWORD(ad->reg.stop, 0x0002);
        STOREINTELWORD(ad->reg.limit, 0xffff);
        ad->stop = 0x000060;
        ad->limit = 0x200000;
        adpcm_update(ad);
}

void adpcm_update(ADPCM ad) {

        UINT32  addr;

        if (adpcmcfg.rate) {
                ad->base = ADTIMING * (OPNA_CLOCK / 72) / adpcmcfg.rate;
        }
        addr = LOADINTELWORD(ad->reg.delta);
        addr = (addr * ad->base) >> 16;
        if (addr < 0x80) {
                addr = 0x80;
        }
        ad->step = addr;
        ad->pertim = (1 << (ADTIMING_BIT * 2)) / addr;
        ad->level = (ad->reg.level * adpcmcfg.vol) >> 4;
}

void adpcm_setreg(ADPCM ad, UINT reg, REG8 value) {

        UINT32  addr;

        sound_sync();
        ((UINT8 *)(&ad->reg))[reg] = value;
        switch(reg) {
                case 0x00:                                                              // control1
                        if ((value & 0x80) && (!ad->play)) {
                                ad->play = 0x20;
                                ad->pos = ad->start;
                                ad->samp = 0;
                                ad->delta = 127;
                                ad->remain = 0;
                        }
                        if (value & 1) {
                                ad->play = 0;
                        }
                        break;

                case 0x01:                                                              // control2
                        break;

                case 0x02:      case 0x03:                                      // start address
                        addr = (LOADINTELWORD(ad->reg.start)) << 5;
                        ad->pos = addr;
                        ad->start = addr;
                        break;

                case 0x04:      case 0x05:                                      // stop address
                        addr = (LOADINTELWORD(ad->reg.stop) + 1) << 5;
                        ad->stop = addr;
                        break;

                case 0x08:                                                              // data
                        if ((ad->reg.ctrl1 & 0x60) == 0x60) {
                                adpcm_datawrite(ad, value);
                        }
                        break;

                case 0x09:      case 0x0a:                                      // delta
                        addr = LOADINTELWORD(ad->reg.delta);
                        addr = (addr * ad->base) >> 16;
                        if (addr < 0x80) {
                                addr = 0x80;
                        }
                        ad->step = addr;
                        ad->pertim = (1 << (ADTIMING_BIT * 2)) / addr;
                        break;

                case 0x0b:                                                              // level
                        ad->level = (value * adpcmcfg.vol) >> 4;
                        break;

                case 0x0c:      case 0x0d:                                      // limit address
                        addr = (LOADINTELWORD(ad->reg.limit) + 1) << 5;
                        ad->limit = addr;
                        break;

                case 0x10:                                                              // flag
                        if (value & 0x80) {
                                ad->status = 0;
                        }
                        else {
                                ad->mask = ~(value & 0x1f);
                        }
                        break;
        }
}

REG8 adpcm_status(ADPCM ad) {

        return(((ad->status | 8) & ad->mask) | ad->play);
}