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Diffstat (limited to 'src/hw/audio/gusemu_mixer.c')
| -rw-r--r-- | src/hw/audio/gusemu_mixer.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/src/hw/audio/gusemu_mixer.c b/src/hw/audio/gusemu_mixer.c new file mode 100644 index 0000000..6d8d9ce --- /dev/null +++ b/src/hw/audio/gusemu_mixer.c @@ -0,0 +1,240 @@ +/* + * GUSEMU32 - mixing engine (similar to Interwave GF1 compatibility) + * + * Copyright (C) 2000-2007 Tibor "TS" Schütz + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "gusemu.h" +#include "gustate.h" + +#define GUSregb(position) (* (gusptr+(position))) +#define GUSregw(position) (*(GUSword *) (gusptr+(position))) +#define GUSregd(position) (*(GUSdword *)(gusptr+(position))) + +#define GUSvoice(position) (*(GUSword *)(voiceptr+(position))) + +/* samples are always 16bit stereo (4 bytes each, first right then left interleaved) */ +void gus_mixvoices(GUSEmuState * state, unsigned int playback_freq, unsigned int numsamples, + GUSsample *bufferpos) +{ + /* note that byte registers are stored in the upper half of each voice register! */ + GUSbyte *gusptr; + int Voice; + GUSword *voiceptr; + + unsigned int count; + for (count = 0; count < numsamples * 2; count++) + *(bufferpos + count) = 0; /* clear */ + + gusptr = state->gusdatapos; + voiceptr = (GUSword *) gusptr; + if (!(GUSregb(GUS4cReset) & 0x01)) /* reset flag active? */ + return; + + for (Voice = 0; Voice <= (GUSregb(NumVoices) & 31); Voice++) + { + if (GUSvoice(wVSRControl) & 0x200) + GUSvoice(wVSRControl) |= 0x100; /* voice stop request */ + if (GUSvoice(wVSRVolRampControl) & 0x200) + GUSvoice(wVSRVolRampControl) |= 0x100; /* Volume ramp stop request */ + if (!(GUSvoice(wVSRControl) & GUSvoice(wVSRVolRampControl) & 0x100)) /* neither voice nor volume calculation active - save some time here ;) */ + { + unsigned int sample; + + unsigned int LoopStart = (GUSvoice(wVSRLoopStartHi) << 16) | GUSvoice(wVSRLoopStartLo); /* 23.9 format */ + unsigned int LoopEnd = (GUSvoice(wVSRLoopEndHi) << 16) | GUSvoice(wVSRLoopEndLo); /* 23.9 format */ + unsigned int CurrPos = (GUSvoice(wVSRCurrPosHi) << 16) | GUSvoice(wVSRCurrPosLo); /* 23.9 format */ + int VoiceIncrement = ((((unsigned long) GUSvoice(wVSRFreq) * 44100) / playback_freq) * (14 >> 1)) / + ((GUSregb(NumVoices) & 31) + 1); /* 6.10 increment/frame to 23.9 increment/sample */ + + int PanningPos = (GUSvoice(wVSRPanning) >> 8) & 0xf; + + unsigned int Volume32 = 32 * GUSvoice(wVSRCurrVol); /* 32 times larger than original gus for maintaining precision while ramping */ + unsigned int StartVol32 = (GUSvoice(wVSRVolRampStartVol) & 0xff00) * 32; + unsigned int EndVol32 = (GUSvoice(wVSRVolRampEndVol) & 0xff00) * 32; + int VolumeIncrement32 = (32 * 16 * (GUSvoice(wVSRVolRampRate) & 0x3f00) >> 8) >> ((((GUSvoice(wVSRVolRampRate) & 0xc000) >> 8) >> 6) * 3); /* including 1/8/64/512 volume speed divisor */ + VolumeIncrement32 = (((VolumeIncrement32 * 44100 / 2) / playback_freq) * 14) / ((GUSregb(NumVoices) & 31) + 1); /* adjust ramping speed to playback speed */ + + if (GUSvoice(wVSRControl) & 0x4000) + VoiceIncrement = -VoiceIncrement; /* reverse playback */ + if (GUSvoice(wVSRVolRampControl) & 0x4000) + VolumeIncrement32 = -VolumeIncrement32; /* reverse ramping */ + + for (sample = 0; sample < numsamples; sample++) + { + int sample1, sample2, Volume; + if (GUSvoice(wVSRControl) & 0x400) /* 16bit */ + { + int offset = ((CurrPos >> 9) & 0xc0000) + (((CurrPos >> 9) & 0x1ffff) << 1); + GUSchar *adr; + adr = (GUSchar *) state->himemaddr + offset; + sample1 = (*adr & 0xff) + (*(adr + 1) * 256); + sample2 = (*(adr + 2) & 0xff) + (*(adr + 2 + 1) * 256); + } + else /* 8bit */ + { + int offset = (CurrPos >> 9) & 0xfffff; + GUSchar *adr; + adr = (GUSchar *) state->himemaddr + offset; + sample1 = (*adr) * 256; + sample2 = (*(adr + 1)) * 256; + } + + Volume = ((((Volume32 >> (4 + 5)) & 0xff) + 256) << (Volume32 >> ((4 + 8) + 5))) / 512; /* semi-logarithmic volume, +5 due to additional precision */ + sample1 = (((sample1 * Volume) >> 16) * (512 - (CurrPos % 512))) / 512; + sample2 = (((sample2 * Volume) >> 16) * (CurrPos % 512)) / 512; + sample1 += sample2; + + if (!(GUSvoice(wVSRVolRampControl) & 0x100)) + { + Volume32 += VolumeIncrement32; + if ((GUSvoice(wVSRVolRampControl) & 0x4000) ? (Volume32 <= StartVol32) : (Volume32 >= EndVol32)) /* ramp up boundary cross */ + { + if (GUSvoice(wVSRVolRampControl) & 0x2000) + GUSvoice(wVSRVolRampControl) |= 0x8000; /* volramp IRQ enabled? -> IRQ wait flag */ + if (GUSvoice(wVSRVolRampControl) & 0x800) /* loop enabled */ + { + if (GUSvoice(wVSRVolRampControl) & 0x1000) /* bidir. loop */ + { + GUSvoice(wVSRVolRampControl) ^= 0x4000; /* toggle dir */ + VolumeIncrement32 = -VolumeIncrement32; + } + else + Volume32 = (GUSvoice(wVSRVolRampControl) & 0x4000) ? EndVol32 : StartVol32; /* unidir. loop ramp */ + } + else + { + GUSvoice(wVSRVolRampControl) |= 0x100; + Volume32 = + (GUSvoice(wVSRVolRampControl) & 0x4000) ? StartVol32 : EndVol32; + } + } + } + if ((GUSvoice(wVSRVolRampControl) & 0xa000) == 0xa000) /* volramp IRQ set and enabled? */ + { + GUSregd(voicevolrampirq) |= 1 << Voice; /* set irq slot */ + } + else + { + GUSregd(voicevolrampirq) &= (~(1 << Voice)); /* clear irq slot */ + GUSvoice(wVSRVolRampControl) &= 0x7f00; + } + + if (!(GUSvoice(wVSRControl) & 0x100)) + { + CurrPos += VoiceIncrement; + if ((GUSvoice(wVSRControl) & 0x4000) ? (CurrPos <= LoopStart) : (CurrPos >= LoopEnd)) /* playback boundary cross */ + { + if (GUSvoice(wVSRControl) & 0x2000) + GUSvoice(wVSRControl) |= 0x8000; /* voice IRQ enabled -> IRQ wait flag */ + if (GUSvoice(wVSRControl) & 0x800) /* loop enabled */ + { + if (GUSvoice(wVSRControl) & 0x1000) /* pingpong loop */ + { + GUSvoice(wVSRControl) ^= 0x4000; /* toggle dir */ + VoiceIncrement = -VoiceIncrement; + } + else + CurrPos = (GUSvoice(wVSRControl) & 0x4000) ? LoopEnd : LoopStart; /* unidir. loop */ + } + else if (!(GUSvoice(wVSRVolRampControl) & 0x400)) + GUSvoice(wVSRControl) |= 0x100; /* loop disabled, rollover check */ + } + } + if ((GUSvoice(wVSRControl) & 0xa000) == 0xa000) /* wavetable IRQ set and enabled? */ + { + GUSregd(voicewavetableirq) |= 1 << Voice; /* set irq slot */ + } + else + { + GUSregd(voicewavetableirq) &= (~(1 << Voice)); /* clear irq slot */ + GUSvoice(wVSRControl) &= 0x7f00; + } + + /* mix samples into buffer */ + *(bufferpos + 2 * sample) += (GUSsample) ((sample1 * PanningPos) >> 4); /* right */ + *(bufferpos + 2 * sample + 1) += (GUSsample) ((sample1 * (15 - PanningPos)) >> 4); /* left */ + } + /* write back voice and volume */ + GUSvoice(wVSRCurrVol) = Volume32 / 32; + GUSvoice(wVSRCurrPosHi) = CurrPos >> 16; + GUSvoice(wVSRCurrPosLo) = CurrPos & 0xffff; + } + voiceptr += 16; /* next voice */ + } +} + +void gus_irqgen(GUSEmuState * state, unsigned int elapsed_time) +/* time given in microseconds */ +{ + int requestedIRQs = 0; + GUSbyte *gusptr; + gusptr = state->gusdatapos; + if (GUSregb(TimerDataReg2x9) & 1) /* start timer 1 (80us decrement rate) */ + { + unsigned int timer1fraction = state->timer1fraction; + int newtimerirqs; + newtimerirqs = (elapsed_time + timer1fraction) / (80 * (256 - GUSregb(GUS46Counter1))); + state->timer1fraction = (elapsed_time + timer1fraction) % (80 * (256 - GUSregb(GUS46Counter1))); + if (newtimerirqs) + { + if (!(GUSregb(TimerDataReg2x9) & 0x40)) + GUSregb(TimerStatus2x8) |= 0xc0; /* maskable bits */ + if (GUSregb(GUS45TimerCtrl) & 4) /* timer1 irq enable */ + { + GUSregb(TimerStatus2x8) |= 4; /* nonmaskable bit */ + GUSregb(IRQStatReg2x6) |= 4; /* timer 1 irq pending */ + GUSregw(TimerIRQs) += newtimerirqs; + requestedIRQs += newtimerirqs; + } + } + } + if (GUSregb(TimerDataReg2x9) & 2) /* start timer 2 (320us decrement rate) */ + { + unsigned int timer2fraction = state->timer2fraction; + int newtimerirqs; + newtimerirqs = (elapsed_time + timer2fraction) / (320 * (256 - GUSregb(GUS47Counter2))); + state->timer2fraction = (elapsed_time + timer2fraction) % (320 * (256 - GUSregb(GUS47Counter2))); + if (newtimerirqs) + { + if (!(GUSregb(TimerDataReg2x9) & 0x20)) + GUSregb(TimerStatus2x8) |= 0xa0; /* maskable bits */ + if (GUSregb(GUS45TimerCtrl) & 8) /* timer2 irq enable */ + { + GUSregb(TimerStatus2x8) |= 2; /* nonmaskable bit */ + GUSregb(IRQStatReg2x6) |= 8; /* timer 2 irq pending */ + GUSregw(TimerIRQs) += newtimerirqs; + requestedIRQs += newtimerirqs; + } + } + } + if (GUSregb(GUS4cReset) & 0x4) /* synth IRQ enable */ + { + if (GUSregd(voicewavetableirq)) + GUSregb(IRQStatReg2x6) |= 0x20; + if (GUSregd(voicevolrampirq)) + GUSregb(IRQStatReg2x6) |= 0x40; + } + if ((!requestedIRQs) && GUSregb(IRQStatReg2x6)) + requestedIRQs++; + if (GUSregb(IRQStatReg2x6)) + GUSregw(BusyTimerIRQs) = GUS_irqrequest(state, state->gusirq, requestedIRQs); +} |
