/* HuC6280 sound chip emulator by Charles MacDonald E-mail: cgfm2@hotmail.com WWW: http://cgfm2.emuviews.com Thanks to: - Paul Clifford for his PSG documentation. - Richard Bannister for the TGEmu-specific sound updating code. - http://www.uspto.gov for the PSG patents. - All contributors to the tghack-list. Changes: (03/30/2003) - Removed TGEmu specific code and added support functions for MAME. - Modified setup code to handle multiple chips with different clock and volume settings. Missing features / things to do: - Add LFO support. But do any games actually use it? - Add shared index for waveform playback and sample writes. Almost every game will reset the index prior to playback so this isn't an issue. - While the noise emulation is complete, the data for the pseudo-random bitstream is calculated by mame_rand() and is not a representation of what the actual hardware does. For some background on Hudson Soft's C62 chipset: - http://www.hudsonsoft.net/ww/about/about.html - http://www.hudson.co.jp/corp/eng/coinfo/history.html Legal information: Copyright Charles MacDonald This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "sndintrf.h" #include "streams.h" #include "c6280.h" typedef struct { UINT16 frequency; UINT8 control; UINT8 balance; UINT8 waveform[32]; UINT8 index; INT16 dda; UINT8 noise_control; UINT32 noise_counter; UINT32 counter; } t_channel; typedef struct { sound_stream *stream; const device_config *device; UINT8 select; UINT8 balance; UINT8 lfo_frequency; UINT8 lfo_control; t_channel channel[8]; INT16 volume_table[32]; UINT32 noise_freq_tab[32]; UINT32 wave_freq_tab[4096]; } c6280_t; /* only needed for io_buffer */ #include "cpu/h6280/h6280.h" static void c6280_init(const device_config *device, c6280_t *p, double clk, double rate) { int i; double step; /* Loudest volume level for table */ double level = 65535.0 / 6.0 / 32.0; /* Clear context */ memset(p, 0, sizeof(c6280_t)); p->device = device; /* Make waveform frequency table */ for(i = 0; i < 4096; i += 1) { step = ((clk / rate) * 4096) / (i+1); p->wave_freq_tab[(1 + i) & 0xFFF] = (UINT32)step; } /* Make noise frequency table */ for(i = 0; i < 32; i += 1) { step = ((clk / rate) * 32) / (i+1); p->noise_freq_tab[i] = (UINT32)step; } /* Make volume table */ /* PSG has 48dB volume range spread over 32 steps */ step = 48.0 / 32.0; for(i = 0; i < 31; i++) { p->volume_table[i] = (UINT16)level; level /= pow(10.0, step / 20.0); } p->volume_table[31] = 0; } static void c6280_write(c6280_t *p, int offset, int data) { t_channel *q = &p->channel[p->select]; /* Update stream */ stream_update(p->stream); switch(offset & 0x0F) { case 0x00: /* Channel select */ p->select = data & 0x07; break; case 0x01: /* Global balance */ p->balance = data; break; case 0x02: /* Channel frequency (LSB) */ q->frequency = (q->frequency & 0x0F00) | data; q->frequency &= 0x0FFF; break; case 0x03: /* Channel frequency (MSB) */ q->frequency = (q->frequency & 0x00FF) | (data << 8); q->frequency &= 0x0FFF; break; case 0x04: /* Channel control (key-on, DDA mode, volume) */ /* 1-to-0 transition of DDA bit resets waveform index */ if((q->control & 0x40) && ((data & 0x40) == 0)) { q->index = 0; } q->control = data; break; case 0x05: /* Channel balance */ q->balance = data; break; case 0x06: /* Channel waveform data */ switch(q->control & 0xC0) { case 0x00: q->waveform[q->index & 0x1F] = data & 0x1F; q->index = (q->index + 1) & 0x1F; break; case 0x40: break; case 0x80: q->waveform[q->index & 0x1F] = data & 0x1F; q->index = (q->index + 1) & 0x1F; break; case 0xC0: q->dda = data & 0x1F; break; } break; case 0x07: /* Noise control (enable, frequency) */ q->noise_control = data; break; case 0x08: /* LFO frequency */ p->lfo_frequency = data; break; case 0x09: /* LFO control (enable, mode) */ p->lfo_control = data; break; default: break; } } static void c6280_update(void *param, stream_sample_t **inputs, stream_sample_t **buffer, int length) { static const int scale_tab[] = { 0x00, 0x03, 0x05, 0x07, 0x09, 0x0B, 0x0D, 0x0F, 0x10, 0x13, 0x15, 0x17, 0x19, 0x1B, 0x1D, 0x1F }; int ch; int i; c6280_t *p = param; int lmal = (p->balance >> 4) & 0x0F; int rmal = (p->balance >> 0) & 0x0F; int vll, vlr; lmal = scale_tab[lmal]; rmal = scale_tab[rmal]; /* Clear buffer */ for(i = 0; i < length; i++) { buffer[0][i] = 0; buffer[1][i] = 0; } for(ch = 0; ch < 6; ch++) { /* Only look at enabled channels */ if(p->channel[ch].control & 0x80) { int lal = (p->channel[ch].balance >> 4) & 0x0F; int ral = (p->channel[ch].balance >> 0) & 0x0F; int al = p->channel[ch].control & 0x1F; lal = scale_tab[lal]; ral = scale_tab[ral]; /* Calculate volume just as the patent says */ vll = (0x1F - lal) + (0x1F - al) + (0x1F - lmal); if(vll > 0x1F) vll = 0x1F; vlr = (0x1F - ral) + (0x1F - al) + (0x1F - rmal); if(vlr > 0x1F) vlr = 0x1F; vll = p->volume_table[vll]; vlr = p->volume_table[vlr]; /* Check channel mode */ if((ch >= 4) && (p->channel[ch].noise_control & 0x80)) { /* Noise mode */ UINT32 step = p->noise_freq_tab[(p->channel[ch].noise_control & 0x1F) ^ 0x1F]; for(i = 0; i < length; i += 1) { static int data = 0; p->channel[ch].noise_counter += step; if(p->channel[ch].noise_counter >= 0x800) { data = (mame_rand(p->device->machine) & 1) ? 0x1F : 0; } p->channel[ch].noise_counter &= 0x7FF; buffer[0][i] += (INT16)(vll * (data - 16)); buffer[1][i] += (INT16)(vlr * (data - 16)); } } else if(p->channel[ch].control & 0x40) { /* DDA mode */ for(i = 0; i < length; i++) { buffer[0][i] += (INT16)(vll * (p->channel[ch].dda - 16)); buffer[1][i] += (INT16)(vlr * (p->channel[ch].dda - 16)); } } else { /* Waveform mode */ UINT32 step = p->wave_freq_tab[p->channel[ch].frequency]; for(i = 0; i < length; i += 1) { int offset; INT16 data; offset = (p->channel[ch].counter >> 12) & 0x1F; p->channel[ch].counter += step; p->channel[ch].counter &= 0x1FFFF; data = p->channel[ch].waveform[offset]; buffer[0][i] += (INT16)(vll * (data - 16)); buffer[1][i] += (INT16)(vlr * (data - 16)); } } } } } /*--------------------------------------------------------------------------*/ /* MAME specific code */ /*--------------------------------------------------------------------------*/ static SND_START( c6280 ) { int rate = clock/16; c6280_t *info; info = auto_malloc(sizeof(*info)); memset(info, 0, sizeof(*info)); /* Initialize PSG emulator */ c6280_init(device, info, clock, rate); /* Create stereo stream */ info->stream = stream_create(device, 0, 2, rate, info, c6280_update); return info; } READ8_HANDLER( c6280_r ) { return h6280io_get_buffer((device_config*)space->cpu); } WRITE8_HANDLER( c6280_0_w ) { h6280io_set_buffer((device_config*)space->cpu, data); c6280_write(sndti_token(SOUND_C6280, 0),offset,data); } WRITE8_HANDLER( c6280_1_w ) { h6280io_set_buffer((device_config*)space->cpu, data); c6280_write(sndti_token(SOUND_C6280, 1),offset,data); } /************************************************************************** * Generic get_info **************************************************************************/ static SND_SET_INFO( c6280 ) { switch (state) { /* no parameters to set */ } } SND_GET_INFO( c6280 ) { switch (state) { /* --- the following bits of info are returned as 64-bit signed integers --- */ /* --- 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( c6280 ); break; case SNDINFO_PTR_START: info->start = SND_START_NAME( c6280 ); break; case SNDINFO_PTR_STOP: /* nothing */ break; case SNDINFO_PTR_RESET: /* nothing */ break; /* --- the following bits of info are returned as NULL-terminated strings --- */ case SNDINFO_STR_NAME: info->s = "HuC6280"; break; case SNDINFO_STR_CORE_FAMILY: info->s = "????"; break; case SNDINFO_STR_CORE_VERSION: info->s = "1.0"; break; case SNDINFO_STR_CORE_FILE: info->s = __FILE__; break; case SNDINFO_STR_CORE_CREDITS: info->s = "Copyright Nicola Salmoria and the MAME Team"; break; } }