/********************************************************* Irem GA20 PCM Sound Chip It's not currently known whether this chip is stereo. Revisions: 04-15-2002 Acho A. Tang - rewrote channel mixing - added prelimenary volume and sample rate emulation 05-30-2002 Acho A. Tang - applied hyperbolic gain control to volume and used a musical-note style progression in sample rate calculation(still very inaccurate) 02-18-2004 R. Belmont - sample rate calculation reverse-engineered. Thanks to Fujix, Yasuhiro Ogawa, the Guru, and Tormod for real PCB samples that made this possible. 02-03-2007 R. Belmont - Cleaned up faux x86 assembly. *********************************************************/ #include #include "sndintrf.h" #include "streams.h" #include "iremga20.h" #define MAX_VOL 256 struct IremGA20_channel_def { UINT32 rate; UINT32 size; UINT32 start; UINT32 pos; UINT32 frac; UINT32 end; UINT32 volume; UINT32 pan; UINT32 effect; UINT32 play; }; struct IremGA20_chip_def { UINT8 *rom; INT32 rom_size; sound_stream * stream; UINT16 regs[0x40]; struct IremGA20_channel_def channel[4]; }; static STREAM_UPDATE( IremGA20_update ) { struct IremGA20_chip_def *chip = param; UINT32 rate[4], pos[4], frac[4], end[4], vol[4], play[4]; UINT8 *pSamples; stream_sample_t *outL, *outR; int i, sampleout; /* precache some values */ for (i=0; i < 4; i++) { rate[i] = chip->channel[i].rate; pos[i] = chip->channel[i].pos; frac[i] = chip->channel[i].frac; end[i] = chip->channel[i].end - 0x20; vol[i] = chip->channel[i].volume; play[i] = chip->channel[i].play; } i = samples; pSamples = chip->rom; outL = outputs[0]; outR = outputs[1]; for (i = 0; i < samples; i++) { sampleout = 0; // update the 4 channels inline if (play[0]) { sampleout += (pSamples[pos[0]] - 0x80) * vol[0]; frac[0] += rate[0]; pos[0] += frac[0] >> 24; frac[0] &= 0xffffff; play[0] = (pos[0] < end[0]); } if (play[1]) { sampleout += (pSamples[pos[1]] - 0x80) * vol[1]; frac[1] += rate[1]; pos[1] += frac[1] >> 24; frac[1] &= 0xffffff; play[1] = (pos[1] < end[1]); } if (play[2]) { sampleout += (pSamples[pos[2]] - 0x80) * vol[2]; frac[2] += rate[2]; pos[2] += frac[2] >> 24; frac[2] &= 0xffffff; play[2] = (pos[2] < end[2]); } if (play[3]) { sampleout += (pSamples[pos[3]] - 0x80) * vol[3]; frac[3] += rate[3]; pos[3] += frac[3] >> 24; frac[3] &= 0xffffff; play[3] = (pos[3] < end[3]); } sampleout >>= 2; outL[i] = sampleout; outR[i] = sampleout; } /* update the regs now */ for (i=0; i < 4; i++) { chip->channel[i].pos = pos[i]; chip->channel[i].frac = frac[i]; chip->channel[i].play = play[i]; } } WRITE16_HANDLER( irem_ga20_w ) { struct IremGA20_chip_def *chip = sndti_token(SOUND_IREMGA20, 0); int channel; /* only low byte hooked up? */ if (!ACCESSING_BITS_0_7) return; //logerror("GA20: Offset %02x, data %04x\n",offset,data); stream_update(chip->stream); channel = offset >> 3; chip->regs[offset] = data; switch (offset & 0x7) { case 0: /* start address low */ chip->channel[channel].start = ((chip->channel[channel].start)&0xff000) | (data<<4); break; case 1: /* start address high */ chip->channel[channel].start = ((chip->channel[channel].start)&0x00ff0) | (data<<12); break; case 2: /* end address low */ chip->channel[channel].end = ((chip->channel[channel].end)&0xff000) | (data<<4); break; case 3: /* end address high */ chip->channel[channel].end = ((chip->channel[channel].end)&0x00ff0) | (data<<12); break; case 4: chip->channel[channel].rate = 0x1000000 / (256 - data); break; case 5: //AT: gain control chip->channel[channel].volume = (data * MAX_VOL) / (data + 10); break; case 6: //AT: this is always written 2(enabling both channels?) chip->channel[channel].play = data; chip->channel[channel].pos = chip->channel[channel].start; chip->channel[channel].frac = 0; break; } } READ16_HANDLER( irem_ga20_r ) { struct IremGA20_chip_def *chip = sndti_token(SOUND_IREMGA20, 0); int channel; stream_update(chip->stream); channel = offset >> 3; switch (offset & 0x7) { case 7: // voice status. bit 0 is 1 if active. (routine around 0xccc in rtypeleo) return chip->channel[channel].play ? 1 : 0; default: logerror("GA20: read unk. register %d, channel %d\n", offset & 0xf, channel); break; } return 0; } static void iremga20_reset(struct IremGA20_chip_def *chip) { int i; for( i = 0; i < 4; i++ ) { chip->channel[i].rate = 0; chip->channel[i].size = 0; chip->channel[i].start = 0; chip->channel[i].pos = 0; chip->channel[i].frac = 0; chip->channel[i].end = 0; chip->channel[i].volume = 0; chip->channel[i].pan = 0; chip->channel[i].effect = 0; chip->channel[i].play = 0; } } static SND_RESET( iremga20 ) { iremga20_reset(device->token); } static SND_START( iremga20 ) { struct IremGA20_chip_def *chip = device->token; int i; /* Initialize our chip structure */ chip->rom = device->region; chip->rom_size = device->regionbytes; iremga20_reset(chip); for ( i = 0; i < 0x40; i++ ) chip->regs[i] = 0; chip->stream = stream_create( device, 0, 2, clock/4, chip, IremGA20_update ); state_save_register_device_item_array(device, 0, chip->regs); for (i = 0; i < 4; i++) { state_save_register_device_item(device, i, chip->channel[i].rate); state_save_register_device_item(device, i, chip->channel[i].size); state_save_register_device_item(device, i, chip->channel[i].start); state_save_register_device_item(device, i, chip->channel[i].pos); state_save_register_device_item(device, i, chip->channel[i].end); state_save_register_device_item(device, i, chip->channel[i].volume); state_save_register_device_item(device, i, chip->channel[i].pan); state_save_register_device_item(device, i, chip->channel[i].effect); state_save_register_device_item(device, i, chip->channel[i].play); } return DEVICE_START_OK; } /************************************************************************** * Generic get_info **************************************************************************/ static SND_SET_INFO( iremga20 ) { switch (state) { /* no parameters to set */ } } SND_GET_INFO( iremga20 ) { switch (state) { /* --- the following bits of info are returned as 64-bit signed integers --- */ case SNDINFO_INT_TOKEN_BYTES: info->i = sizeof(struct IremGA20_chip_def); break; /* --- the following bits of info are returned as pointers to data or functions --- */ case SNDINFO_PTR_SET_INFO: info->set_info = SND_SET_INFO_NAME( iremga20 ); break; case SNDINFO_PTR_START: info->start = SND_START_NAME( iremga20 ); break; case SNDINFO_PTR_STOP: /* nothing */ break; case SNDINFO_PTR_RESET: info->reset = SND_RESET_NAME( iremga20 ); break; /* --- the following bits of info are returned as NULL-terminated strings --- */ case SNDINFO_STR_NAME: strcpy(info->s, "Irem GA20"); break; case SNDINFO_STR_CORE_FAMILY: strcpy(info->s, "Irem custom"); break; case SNDINFO_STR_CORE_VERSION: strcpy(info->s, "1.0"); break; case SNDINFO_STR_CORE_FILE: strcpy(info->s, __FILE__); break; case SNDINFO_STR_CORE_CREDITS: strcpy(info->s, "Copyright Nicola Salmoria and the MAME Team"); break; } }