1 /* 2 * GUSEMU32 - mixing engine (similar to Interwave GF1 compatibility) 3 * 4 * Copyright (C) 2000-2007 Tibor "TS" Schütz 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 25 #include "gusemu.h" 26 #include "gustate.h" 27 28 #define GUSregb(position) (* (gusptr+(position))) 29 #define GUSregw(position) (*(GUSword *) (gusptr+(position))) 30 #define GUSregd(position) (*(GUSdword *)(gusptr+(position))) 31 32 #define GUSvoice(position) (*(GUSword *)(voiceptr+(position))) 33 34 /* samples are always 16bit stereo (4 bytes each, first right then left interleaved) */ 35 void gus_mixvoices(GUSEmuState * state, unsigned int playback_freq, unsigned int numsamples, 36 GUSsample *bufferpos) 37 { 38 /* note that byte registers are stored in the upper half of each voice register! */ 39 GUSbyte *gusptr; 40 int Voice; 41 GUSword *voiceptr; 42 43 unsigned int count; 44 for (count = 0; count < numsamples * 2; count++) 45 *(bufferpos + count) = 0; /* clear */ 46 47 gusptr = state->gusdatapos; 48 voiceptr = (GUSword *) gusptr; 49 if (!(GUSregb(GUS4cReset) & 0x01)) /* reset flag active? */ 50 return; 51 52 for (Voice = 0; Voice <= (GUSregb(NumVoices) & 31); Voice++) 53 { 54 if (GUSvoice(wVSRControl) & 0x200) 55 GUSvoice(wVSRControl) |= 0x100; /* voice stop request */ 56 if (GUSvoice(wVSRVolRampControl) & 0x200) 57 GUSvoice(wVSRVolRampControl) |= 0x100; /* Volume ramp stop request */ 58 if (!(GUSvoice(wVSRControl) & GUSvoice(wVSRVolRampControl) & 0x100)) /* neither voice nor volume calculation active - save some time here ;) */ 59 { 60 unsigned int sample; 61 62 unsigned int LoopStart = (GUSvoice(wVSRLoopStartHi) << 16) | GUSvoice(wVSRLoopStartLo); /* 23.9 format */ 63 unsigned int LoopEnd = (GUSvoice(wVSRLoopEndHi) << 16) | GUSvoice(wVSRLoopEndLo); /* 23.9 format */ 64 unsigned int CurrPos = (GUSvoice(wVSRCurrPosHi) << 16) | GUSvoice(wVSRCurrPosLo); /* 23.9 format */ 65 int VoiceIncrement = ((((unsigned long) GUSvoice(wVSRFreq) * 44100) / playback_freq) * (14 >> 1)) / 66 ((GUSregb(NumVoices) & 31) + 1); /* 6.10 increment/frame to 23.9 increment/sample */ 67 68 int PanningPos = (GUSvoice(wVSRPanning) >> 8) & 0xf; 69 70 unsigned int Volume32 = 32 * GUSvoice(wVSRCurrVol); /* 32 times larger than original gus for maintaining precision while ramping */ 71 unsigned int StartVol32 = (GUSvoice(wVSRVolRampStartVol) & 0xff00) * 32; 72 unsigned int EndVol32 = (GUSvoice(wVSRVolRampEndVol) & 0xff00) * 32; 73 int VolumeIncrement32 = (32 * 16 * (GUSvoice(wVSRVolRampRate) & 0x3f00) >> 8) >> ((((GUSvoice(wVSRVolRampRate) & 0xc000) >> 8) >> 6) * 3); /* including 1/8/64/512 volume speed divisor */ 74 VolumeIncrement32 = (((VolumeIncrement32 * 44100 / 2) / playback_freq) * 14) / ((GUSregb(NumVoices) & 31) + 1); /* adjust ramping speed to playback speed */ 75 76 if (GUSvoice(wVSRControl) & 0x4000) 77 VoiceIncrement = -VoiceIncrement; /* reverse playback */ 78 if (GUSvoice(wVSRVolRampControl) & 0x4000) 79 VolumeIncrement32 = -VolumeIncrement32; /* reverse ramping */ 80 81 for (sample = 0; sample < numsamples; sample++) 82 { 83 int sample1, sample2, Volume; 84 if (GUSvoice(wVSRControl) & 0x400) /* 16bit */ 85 { 86 int offset = ((CurrPos >> 9) & 0xc0000) + (((CurrPos >> 9) & 0x1ffff) << 1); 87 GUSchar *adr; 88 adr = (GUSchar *) state->himemaddr + offset; 89 sample1 = (*adr & 0xff) + (*(adr + 1) * 256); 90 sample2 = (*(adr + 2) & 0xff) + (*(adr + 2 + 1) * 256); 91 } 92 else /* 8bit */ 93 { 94 int offset = (CurrPos >> 9) & 0xfffff; 95 GUSchar *adr; 96 adr = (GUSchar *) state->himemaddr + offset; 97 sample1 = (*adr) * 256; 98 sample2 = (*(adr + 1)) * 256; 99 } 100 101 Volume = ((((Volume32 >> (4 + 5)) & 0xff) + 256) << (Volume32 >> ((4 + 8) + 5))) / 512; /* semi-logarithmic volume, +5 due to additional precision */ 102 sample1 = (((sample1 * Volume) >> 16) * (512 - (CurrPos % 512))) / 512; 103 sample2 = (((sample2 * Volume) >> 16) * (CurrPos % 512)) / 512; 104 sample1 += sample2; 105 106 if (!(GUSvoice(wVSRVolRampControl) & 0x100)) 107 { 108 Volume32 += VolumeIncrement32; 109 if ((GUSvoice(wVSRVolRampControl) & 0x4000) ? (Volume32 <= StartVol32) : (Volume32 >= EndVol32)) /* ramp up boundary cross */ 110 { 111 if (GUSvoice(wVSRVolRampControl) & 0x2000) 112 GUSvoice(wVSRVolRampControl) |= 0x8000; /* volramp IRQ enabled? -> IRQ wait flag */ 113 if (GUSvoice(wVSRVolRampControl) & 0x800) /* loop enabled */ 114 { 115 if (GUSvoice(wVSRVolRampControl) & 0x1000) /* bidir. loop */ 116 { 117 GUSvoice(wVSRVolRampControl) ^= 0x4000; /* toggle dir */ 118 VolumeIncrement32 = -VolumeIncrement32; 119 } 120 else 121 Volume32 = (GUSvoice(wVSRVolRampControl) & 0x4000) ? EndVol32 : StartVol32; /* unidir. loop ramp */ 122 } 123 else 124 { 125 GUSvoice(wVSRVolRampControl) |= 0x100; 126 Volume32 = 127 (GUSvoice(wVSRVolRampControl) & 0x4000) ? StartVol32 : EndVol32; 128 } 129 } 130 } 131 if ((GUSvoice(wVSRVolRampControl) & 0xa000) == 0xa000) /* volramp IRQ set and enabled? */ 132 { 133 GUSregd(voicevolrampirq) |= 1 << Voice; /* set irq slot */ 134 } 135 else 136 { 137 GUSregd(voicevolrampirq) &= (~(1 << Voice)); /* clear irq slot */ 138 GUSvoice(wVSRVolRampControl) &= 0x7f00; 139 } 140 141 if (!(GUSvoice(wVSRControl) & 0x100)) 142 { 143 CurrPos += VoiceIncrement; 144 if ((GUSvoice(wVSRControl) & 0x4000) ? (CurrPos <= LoopStart) : (CurrPos >= LoopEnd)) /* playback boundary cross */ 145 { 146 if (GUSvoice(wVSRControl) & 0x2000) 147 GUSvoice(wVSRControl) |= 0x8000; /* voice IRQ enabled -> IRQ wait flag */ 148 if (GUSvoice(wVSRControl) & 0x800) /* loop enabled */ 149 { 150 if (GUSvoice(wVSRControl) & 0x1000) /* pingpong loop */ 151 { 152 GUSvoice(wVSRControl) ^= 0x4000; /* toggle dir */ 153 VoiceIncrement = -VoiceIncrement; 154 } 155 else 156 CurrPos = (GUSvoice(wVSRControl) & 0x4000) ? LoopEnd : LoopStart; /* unidir. loop */ 157 } 158 else if (!(GUSvoice(wVSRVolRampControl) & 0x400)) 159 GUSvoice(wVSRControl) |= 0x100; /* loop disabled, rollover check */ 160 } 161 } 162 if ((GUSvoice(wVSRControl) & 0xa000) == 0xa000) /* wavetable IRQ set and enabled? */ 163 { 164 GUSregd(voicewavetableirq) |= 1 << Voice; /* set irq slot */ 165 } 166 else 167 { 168 GUSregd(voicewavetableirq) &= (~(1 << Voice)); /* clear irq slot */ 169 GUSvoice(wVSRControl) &= 0x7f00; 170 } 171 172 /* mix samples into buffer */ 173 *(bufferpos + 2 * sample) += (GUSsample) ((sample1 * PanningPos) >> 4); /* right */ 174 *(bufferpos + 2 * sample + 1) += (GUSsample) ((sample1 * (15 - PanningPos)) >> 4); /* left */ 175 } 176 /* write back voice and volume */ 177 GUSvoice(wVSRCurrVol) = Volume32 / 32; 178 GUSvoice(wVSRCurrPosHi) = CurrPos >> 16; 179 GUSvoice(wVSRCurrPosLo) = CurrPos & 0xffff; 180 } 181 voiceptr += 16; /* next voice */ 182 } 183 } 184 185 void gus_irqgen(GUSEmuState * state, unsigned int elapsed_time) 186 /* time given in microseconds */ 187 { 188 int requestedIRQs = 0; 189 GUSbyte *gusptr; 190 gusptr = state->gusdatapos; 191 if (GUSregb(TimerDataReg2x9) & 1) /* start timer 1 (80us decrement rate) */ 192 { 193 unsigned int timer1fraction = state->timer1fraction; 194 int newtimerirqs; 195 newtimerirqs = (elapsed_time + timer1fraction) / (80 * (256 - GUSregb(GUS46Counter1))); 196 state->timer1fraction = (elapsed_time + timer1fraction) % (80 * (256 - GUSregb(GUS46Counter1))); 197 if (newtimerirqs) 198 { 199 if (!(GUSregb(TimerDataReg2x9) & 0x40)) 200 GUSregb(TimerStatus2x8) |= 0xc0; /* maskable bits */ 201 if (GUSregb(GUS45TimerCtrl) & 4) /* timer1 irq enable */ 202 { 203 GUSregb(TimerStatus2x8) |= 4; /* nonmaskable bit */ 204 GUSregb(IRQStatReg2x6) |= 4; /* timer 1 irq pending */ 205 GUSregw(TimerIRQs) += newtimerirqs; 206 requestedIRQs += newtimerirqs; 207 } 208 } 209 } 210 if (GUSregb(TimerDataReg2x9) & 2) /* start timer 2 (320us decrement rate) */ 211 { 212 unsigned int timer2fraction = state->timer2fraction; 213 int newtimerirqs; 214 newtimerirqs = (elapsed_time + timer2fraction) / (320 * (256 - GUSregb(GUS47Counter2))); 215 state->timer2fraction = (elapsed_time + timer2fraction) % (320 * (256 - GUSregb(GUS47Counter2))); 216 if (newtimerirqs) 217 { 218 if (!(GUSregb(TimerDataReg2x9) & 0x20)) 219 GUSregb(TimerStatus2x8) |= 0xa0; /* maskable bits */ 220 if (GUSregb(GUS45TimerCtrl) & 8) /* timer2 irq enable */ 221 { 222 GUSregb(TimerStatus2x8) |= 2; /* nonmaskable bit */ 223 GUSregb(IRQStatReg2x6) |= 8; /* timer 2 irq pending */ 224 GUSregw(TimerIRQs) += newtimerirqs; 225 requestedIRQs += newtimerirqs; 226 } 227 } 228 } 229 if (GUSregb(GUS4cReset) & 0x4) /* synth IRQ enable */ 230 { 231 if (GUSregd(voicewavetableirq)) 232 GUSregb(IRQStatReg2x6) |= 0x20; 233 if (GUSregd(voicevolrampirq)) 234 GUSregb(IRQStatReg2x6) |= 0x40; 235 } 236 if ((!requestedIRQs) && GUSregb(IRQStatReg2x6)) 237 requestedIRQs++; 238 if (GUSregb(IRQStatReg2x6)) 239 GUSregw(BusyTimerIRQs) = GUS_irqrequest(state, state->gusirq, requestedIRQs); 240 } 241