/********************************************************************************************** * * streaming ADPCM driver * by Aaron Giles * * Library to transcode from an ADPCM source to raw PCM. * Written by Buffoni Mirko in 08/06/97 * References: various sources and documents. * * HJB 08/31/98 * modified to use an automatically selected oversampling factor * for the current sample rate * * Mish 21/7/99 * Updated to allow multiple OKI chips with different sample rates * * R. Belmont 31/10/2003 * Updated to allow a driver to use both MSM6295s and "raw" ADPCM voices (gcpinbal) * Also added some error trapping for MAME_DEBUG builds * **********************************************************************************************/ #include #include "sndintrf.h" #include "streams.h" #include "okim6295.h" #define MAX_SAMPLE_CHUNK 10000 /* struct describing a single playing ADPCM voice */ struct ADPCMVoice { UINT8 playing; /* 1 if we are actively playing */ UINT32 base_offset; /* pointer to the base memory location */ UINT32 sample; /* current sample number */ UINT32 count; /* total samples to play */ struct adpcm_state adpcm;/* current ADPCM state */ UINT32 volume; /* output volume */ }; struct okim6295 { #define OKIM6295_VOICES 4 struct ADPCMVoice voice[OKIM6295_VOICES]; INT32 command; INT32 bank_offset; UINT8 *region_base; /* pointer to the base of the region */ sound_stream *stream; /* which stream are we playing on? */ UINT32 master_clock; /* master clock frequency */ }; /* step size index shift table */ static const int index_shift[8] = { -1, -1, -1, -1, 2, 4, 6, 8 }; /* lookup table for the precomputed difference */ static int diff_lookup[49*16]; /* volume lookup table. The manual lists only 9 steps, ~3dB per step. Given the dB values, that seems to map to a 5-bit volume control. Any volume parameter beyond the 9th index results in silent playback. */ static const int volume_table[16] = { 0x20, // 0 dB 0x16, // -3.2 dB 0x10, // -6.0 dB 0x0b, // -9.2 dB 0x08, // -12.0 dB 0x06, // -14.5 dB 0x04, // -18.0 dB 0x03, // -20.5 dB 0x02, // -24.0 dB 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, }; /* tables computed? */ static int tables_computed = 0; /* useful interfaces */ const okim6295_interface okim6295_interface_pin7high = { 1 }; const okim6295_interface okim6295_interface_pin7low = { 0 }; /********************************************************************************************** compute_tables -- compute the difference tables ***********************************************************************************************/ static void compute_tables(void) { /* nibble to bit map */ static const int nbl2bit[16][4] = { { 1, 0, 0, 0}, { 1, 0, 0, 1}, { 1, 0, 1, 0}, { 1, 0, 1, 1}, { 1, 1, 0, 0}, { 1, 1, 0, 1}, { 1, 1, 1, 0}, { 1, 1, 1, 1}, {-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1}, {-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1} }; int step, nib; /* loop over all possible steps */ for (step = 0; step <= 48; step++) { /* compute the step value */ int stepval = floor(16.0 * pow(11.0 / 10.0, (double)step)); /* loop over all nibbles and compute the difference */ for (nib = 0; nib < 16; nib++) { diff_lookup[step*16 + nib] = nbl2bit[nib][0] * (stepval * nbl2bit[nib][1] + stepval/2 * nbl2bit[nib][2] + stepval/4 * nbl2bit[nib][3] + stepval/8); } } tables_computed = 1; } /********************************************************************************************** reset_adpcm -- reset the ADPCM stream ***********************************************************************************************/ void reset_adpcm(struct adpcm_state *state) { /* make sure we have our tables */ if (!tables_computed) compute_tables(); /* reset the signal/step */ state->signal = -2; state->step = 0; } /********************************************************************************************** clock_adpcm -- clock the next ADPCM byte ***********************************************************************************************/ INT16 clock_adpcm(struct adpcm_state *state, UINT8 nibble) { state->signal += diff_lookup[state->step * 16 + (nibble & 15)]; /* clamp to the maximum */ if (state->signal > 2047) state->signal = 2047; else if (state->signal < -2048) state->signal = -2048; /* adjust the step size and clamp */ state->step += index_shift[nibble & 7]; if (state->step > 48) state->step = 48; else if (state->step < 0) state->step = 0; /* return the signal */ return state->signal; } /********************************************************************************************** generate_adpcm -- general ADPCM decoding routine ***********************************************************************************************/ static void generate_adpcm(struct okim6295 *chip, struct ADPCMVoice *voice, INT16 *buffer, int samples) { /* if this voice is active */ if (voice->playing) { UINT8 *base = chip->region_base + chip->bank_offset + voice->base_offset; int sample = voice->sample; int count = voice->count; /* loop while we still have samples to generate */ while (samples) { /* compute the new amplitude and update the current step */ int nibble = base[sample / 2] >> (((sample & 1) << 2) ^ 4); /* output to the buffer, scaling by the volume */ /* signal in range -2048..2047, volume in range 2..32 => signal * volume / 2 in range -32768..32767 */ *buffer++ = clock_adpcm(&voice->adpcm, nibble) * voice->volume / 2; samples--; /* next! */ if (++sample >= count) { voice->playing = 0; break; } } /* update the parameters */ voice->sample = sample; } /* fill the rest with silence */ while (samples--) *buffer++ = 0; } /********************************************************************************************** * * OKIM 6295 ADPCM chip: * * Command bytes are sent: * * 1xxx xxxx = start of 2-byte command sequence, xxxxxxx is the sample number to trigger * abcd vvvv = second half of command; one of the abcd bits is set to indicate which voice * the v bits seem to be volumed * * 0abc d000 = stop playing; one or more of the abcd bits is set to indicate which voice(s) * * Status is read: * * ???? abcd = one bit per voice, set to 0 if nothing is playing, or 1 if it is active * ***********************************************************************************************/ /********************************************************************************************** okim6295_update -- update the sound chip so that it is in sync with CPU execution ***********************************************************************************************/ static STREAM_UPDATE( okim6295_update ) { struct okim6295 *chip = param; int i; memset(outputs[0], 0, samples * sizeof(*outputs[0])); for (i = 0; i < OKIM6295_VOICES; i++) { struct ADPCMVoice *voice = &chip->voice[i]; stream_sample_t *buffer = outputs[0]; INT16 sample_data[MAX_SAMPLE_CHUNK]; int remaining = samples; /* loop while we have samples remaining */ while (remaining) { int samples = (remaining > MAX_SAMPLE_CHUNK) ? MAX_SAMPLE_CHUNK : remaining; int samp; generate_adpcm(chip, voice, sample_data, samples); for (samp = 0; samp < samples; samp++) *buffer++ += sample_data[samp]; remaining -= samples; } } } /********************************************************************************************** state save support for MAME ***********************************************************************************************/ static void adpcm_state_save_register(struct ADPCMVoice *voice, const device_config *device, int index) { state_save_register_device_item(device, index, voice->playing); state_save_register_device_item(device, index, voice->sample); state_save_register_device_item(device, index, voice->count); state_save_register_device_item(device, index, voice->adpcm.signal); state_save_register_device_item(device, index, voice->adpcm.step); state_save_register_device_item(device, index, voice->volume); state_save_register_device_item(device, index, voice->base_offset); } static void okim6295_state_save_register(struct okim6295 *info, const device_config *device) { int j; state_save_register_device_item(device, 0, info->command); state_save_register_device_item(device, 0, info->bank_offset); for (j = 0; j < OKIM6295_VOICES; j++) adpcm_state_save_register(&info->voice[j], device, j); } /********************************************************************************************** SND_START( okim6295 ) -- start emulation of an OKIM6295-compatible chip ***********************************************************************************************/ static SND_START( okim6295 ) { const okim6295_interface *intf = device->static_config; struct okim6295 *info = device->token; int voice; int divisor = intf->pin7 ? 132 : 165; compute_tables(); info->command = -1; info->bank_offset = 0; info->region_base = device->region; if (intf->rgnoverride != NULL) info->region_base = memory_region(device->machine, intf->rgnoverride); info->master_clock = clock; /* generate the name and create the stream */ info->stream = stream_create(device, 0, 1, clock/divisor, info, okim6295_update); /* initialize the voices */ for (voice = 0; voice < OKIM6295_VOICES; voice++) { /* initialize the rest of the structure */ info->voice[voice].volume = 0; reset_adpcm(&info->voice[voice].adpcm); } okim6295_state_save_register(info, device); /* success */ return DEVICE_START_OK; } /********************************************************************************************** SND_RESET( okim6295 ) -- stop emulation of an OKIM6295-compatible chip ***********************************************************************************************/ static SND_RESET( okim6295 ) { struct okim6295 *info = device->token; int i; stream_update(info->stream); for (i = 0; i < OKIM6295_VOICES; i++) info->voice[i].playing = 0; } /********************************************************************************************** okim6295_set_bank_base -- set the base of the bank for a given voice on a given chip ***********************************************************************************************/ void okim6295_set_bank_base(int which, int base) { struct okim6295 *info = sndti_token(SOUND_OKIM6295, which); stream_update(info->stream); info->bank_offset = base; } /********************************************************************************************** okim6295_set_pin7 -- adjust pin 7, which controls the internal clock division ***********************************************************************************************/ void okim6295_set_pin7(int which, int pin7) { struct okim6295 *info = sndti_token(SOUND_OKIM6295, which); int divisor = pin7 ? 132 : 165; stream_set_sample_rate(info->stream, info->master_clock/divisor); } /********************************************************************************************** okim6295_status_r -- read the status port of an OKIM6295-compatible chip ***********************************************************************************************/ static int okim6295_status_r(int num) { struct okim6295 *info = sndti_token(SOUND_OKIM6295, num); int i, result; result = 0xf0; /* naname expects bits 4-7 to be 1 */ /* set the bit to 1 if something is playing on a given channel */ stream_update(info->stream); for (i = 0; i < OKIM6295_VOICES; i++) { struct ADPCMVoice *voice = &info->voice[i]; /* set the bit if it's playing */ if (voice->playing) result |= 1 << i; } return result; } /********************************************************************************************** okim6295_data_w -- write to the data port of an OKIM6295-compatible chip ***********************************************************************************************/ static void okim6295_data_w(int num, int data) { struct okim6295 *info = sndti_token(SOUND_OKIM6295, num); /* if a command is pending, process the second half */ if (info->command != -1) { int temp = data >> 4, i, start, stop; unsigned char *base; /* the manual explicitly says that it's not possible to start multiple voices at the same time */ if (temp != 0 && temp != 1 && temp != 2 && temp != 4 && temp != 8) popmessage("OKI6295 start %x contact MAMEDEV", temp); /* update the stream */ stream_update(info->stream); /* determine which voice(s) (voice is set by a 1 bit in the upper 4 bits of the second byte) */ for (i = 0; i < OKIM6295_VOICES; i++, temp >>= 1) { if (temp & 1) { struct ADPCMVoice *voice = &info->voice[i]; /* determine the start/stop positions */ base = &info->region_base[info->bank_offset + info->command * 8]; start = ((base[0] << 16) + (base[1] << 8) + base[2]) & 0x3ffff; stop = ((base[3] << 16) + (base[4] << 8) + base[5]) & 0x3ffff; /* set up the voice to play this sample */ if (start < stop) { if (!voice->playing) /* fixes Got-cha and Steel Force */ { voice->playing = 1; voice->base_offset = start; voice->sample = 0; voice->count = 2 * (stop - start + 1); /* also reset the ADPCM parameters */ reset_adpcm(&voice->adpcm); voice->volume = volume_table[data & 0x0f]; } else { logerror("OKIM6295:%d requested to play sample %02x on non-stopped voice\n",num,info->command); } } /* invalid samples go here */ else { logerror("OKIM6295:%d requested to play invalid sample %02x\n",num,info->command); voice->playing = 0; } } } /* reset the command */ info->command = -1; } /* if this is the start of a command, remember the sample number for next time */ else if (data & 0x80) { info->command = data & 0x7f; } /* otherwise, see if this is a silence command */ else { int temp = data >> 3, i; /* update the stream, then turn it off */ stream_update(info->stream); /* determine which voice(s) (voice is set by a 1 bit in bits 3-6 of the command */ for (i = 0; i < 4; i++, temp >>= 1) { if (temp & 1) { struct ADPCMVoice *voice = &info->voice[i]; voice->playing = 0; } } } } /********************************************************************************************** okim6295_status_0_r -- generic status read functions okim6295_status_1_r ***********************************************************************************************/ READ8_HANDLER( okim6295_status_0_r ) { return okim6295_status_r(0); } READ8_HANDLER( okim6295_status_1_r ) { return okim6295_status_r(1); } READ8_HANDLER( okim6295_status_2_r ) { return okim6295_status_r(2); } READ16_HANDLER( okim6295_status_0_lsb_r ) { return okim6295_status_r(0); } READ16_HANDLER( okim6295_status_1_lsb_r ) { return okim6295_status_r(1); } READ16_HANDLER( okim6295_status_2_lsb_r ) { return okim6295_status_r(2); } READ16_HANDLER( okim6295_status_0_msb_r ) { return okim6295_status_r(0) << 8; } READ16_HANDLER( okim6295_status_1_msb_r ) { return okim6295_status_r(1) << 8; } READ16_HANDLER( okim6295_status_2_msb_r ) { return okim6295_status_r(2) << 8; } /********************************************************************************************** okim6295_data_0_w -- generic data write functions okim6295_data_1_w ***********************************************************************************************/ WRITE8_HANDLER( okim6295_data_0_w ) { okim6295_data_w(0, data); } WRITE8_HANDLER( okim6295_data_1_w ) { okim6295_data_w(1, data); } WRITE8_HANDLER( okim6295_data_2_w ) { okim6295_data_w(2, data); } WRITE16_HANDLER( okim6295_data_0_lsb_w ) { if (ACCESSING_BITS_0_7) okim6295_data_w(0, data & 0xff); } WRITE16_HANDLER( okim6295_data_1_lsb_w ) { if (ACCESSING_BITS_0_7) okim6295_data_w(1, data & 0xff); } WRITE16_HANDLER( okim6295_data_2_lsb_w ) { if (ACCESSING_BITS_0_7) okim6295_data_w(2, data & 0xff); } WRITE16_HANDLER( okim6295_data_0_msb_w ) { if (ACCESSING_BITS_8_15) okim6295_data_w(0, data >> 8); } WRITE16_HANDLER( okim6295_data_1_msb_w ) { if (ACCESSING_BITS_8_15) okim6295_data_w(1, data >> 8); } WRITE16_HANDLER( okim6295_data_2_msb_w ) { if (ACCESSING_BITS_8_15) okim6295_data_w(2, data >> 8); } /************************************************************************** * Generic get_info **************************************************************************/ static SND_SET_INFO( okim6295 ) { switch (state) { /* no parameters to set */ } } SND_GET_INFO( okim6295 ) { switch (state) { /* --- the following bits of info are returned as 64-bit signed integers --- */ case SNDINFO_INT_TOKEN_BYTES: info->i = sizeof(struct okim6295); 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( okim6295 ); break; case SNDINFO_PTR_START: info->start = SND_START_NAME( okim6295 ); break; case SNDINFO_PTR_STOP: /* nothing */ break; case SNDINFO_PTR_RESET: info->reset = SND_RESET_NAME( okim6295 ); break; /* --- the following bits of info are returned as NULL-terminated strings --- */ case SNDINFO_STR_NAME: strcpy(info->s, "OKI6295"); break; case SNDINFO_STR_CORE_FAMILY: strcpy(info->s, "OKI ADPCM"); 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; } }