hw/audio/gusemu_mixer.c

   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 "qemu/osdep.h"
  26 #include "gusemu.h"
  27 #include "gustate.h"
  28
  29 #define GUSregb(position)  (*            (gusptr+(position)))
  30 #define GUSregw(position)  (*(uint16_t *) (gusptr+(position)))
  31 #define GUSregd(position)  (*(uint16_t *)(gusptr+(position)))
  32
  33 #define GUSvoice(position) (*(uint16_t *)(voiceptr+(position)))
  34
  35 /* samples are always 16bit stereo (4 bytes each, first right then left interleaved) */
  36 void gus_mixvoices(GUSEmuState * state, unsigned int playback_freq, unsigned int numsamples,
  37                    int16_t *bufferpos)
  38 {
  39     /* note that byte registers are stored in the upper half of each voice register! */
  40     uint8_t        *gusptr;
  41     int             Voice;
  42     uint16_t       *voiceptr;
  43
  44     unsigned int    count;
  45     for (count = 0; count < numsamples * 2; count++)
  46         *(bufferpos + count) = 0;       /* clear */
  47
  48     gusptr = state->gusdatapos;
  49     voiceptr = (uint16_t *) gusptr;
  50     if (!(GUSregb(GUS4cReset) & 0x01))  /* reset flag active? */
  51         return;
  52
  53     for (Voice = 0; Voice <= (GUSregb(NumVoices) & 31); Voice++)
  54     {
  55         if (GUSvoice(wVSRControl)        &  0x200)
  56             GUSvoice(wVSRControl)        |= 0x100; /* voice stop request */
  57         if (GUSvoice(wVSRVolRampControl) &  0x200)
  58             GUSvoice(wVSRVolRampControl) |= 0x100; /* Volume ramp stop request */
  59         if (!(GUSvoice(wVSRControl) & GUSvoice(wVSRVolRampControl) & 0x100)) /* neither voice nor volume calculation active - save some time here ;) */
  60         {
  61             unsigned int    sample;
  62
  63             unsigned int    LoopStart = (GUSvoice(wVSRLoopStartHi) << 16) | GUSvoice(wVSRLoopStartLo); /* 23.9 format */
  64             unsigned int    LoopEnd   = (GUSvoice(wVSRLoopEndHi)   << 16) | GUSvoice(wVSRLoopEndLo);   /* 23.9 format */
  65             unsigned int    CurrPos   = (GUSvoice(wVSRCurrPosHi)   << 16) | GUSvoice(wVSRCurrPosLo);   /* 23.9 format */
  66             int             VoiceIncrement = ((((unsigned long) GUSvoice(wVSRFreq) * 44100) / playback_freq) * (14 >> 1)) /
  67                                              ((GUSregb(NumVoices) & 31) + 1); /* 6.10 increment/frame to 23.9 increment/sample */
  68
  69             int             PanningPos = (GUSvoice(wVSRPanning) >> 8) & 0xf;
  70
  71             unsigned int    Volume32   = 32 * GUSvoice(wVSRCurrVol); /* 32 times larger than original gus for maintaining precision while ramping */
  72             unsigned int    StartVol32 = (GUSvoice(wVSRVolRampStartVol) & 0xff00) * 32;
  73             unsigned int    EndVol32   = (GUSvoice(wVSRVolRampEndVol)   & 0xff00) * 32;
  74             int             VolumeIncrement32 = (32 * 16 * (GUSvoice(wVSRVolRampRate) & 0x3f00) >> 8) >> ((((GUSvoice(wVSRVolRampRate) & 0xc000) >> 8) >> 6) * 3); /* including 1/8/64/512 volume speed divisor */
  75             VolumeIncrement32 = (((VolumeIncrement32 * 44100 / 2) / playback_freq) * 14) / ((GUSregb(NumVoices) & 31) + 1); /* adjust ramping speed to playback speed */
  76
  77             if (GUSvoice(wVSRControl) & 0x4000)
  78                 VoiceIncrement    = -VoiceIncrement;    /* reverse playback */
  79             if (GUSvoice(wVSRVolRampControl) & 0x4000)
  80                 VolumeIncrement32 = -VolumeIncrement32; /* reverse ramping */
  81
  82             for (sample = 0; sample < numsamples; sample++)
  83             {
  84                 int             sample1, sample2, Volume;
  85                 if (GUSvoice(wVSRControl) & 0x400)      /* 16bit */
  86                 {
  87                     int offset = ((CurrPos >> 9) & 0xc0000) + (((CurrPos >> 9) & 0x1ffff) << 1);
  88                     int8_t *adr;
  89                     adr = (int8_t *) state->himemaddr + offset;
  90                     sample1 = (*adr & 0xff) + (*(adr + 1) * 256);
  91                     sample2 = (*(adr + 2) & 0xff) + (*(adr + 2 + 1) * 256);
  92                 }
  93                 else            /* 8bit */
  94                 {
  95                     int offset = (CurrPos >> 9) & 0xfffff;
  96                     int8_t *adr;
  97                     adr = (int8_t *) state->himemaddr + offset;
  98                     sample1 = (*adr) * 256;
  99                     sample2 = (*(adr + 1)) * 256;
 100                 }
 101
 102                 Volume = ((((Volume32 >> (4 + 5)) & 0xff) + 256) << (Volume32 >> ((4 + 8) + 5))) / 512; /* semi-logarithmic volume, +5 due to additional precision */
 103                 sample1 = (((sample1 * Volume) >> 16) * (512 - (CurrPos % 512))) / 512;
 104                 sample2 = (((sample2 * Volume) >> 16) * (CurrPos % 512)) / 512;
 105                 sample1 += sample2;
 106
 107                 if (!(GUSvoice(wVSRVolRampControl) & 0x100))
 108                 {
 109                     Volume32 += VolumeIncrement32;
 110                     if ((GUSvoice(wVSRVolRampControl) & 0x4000) ? (Volume32 <= StartVol32) : (Volume32 >= EndVol32)) /* ramp up boundary cross */
 111                     {
 112                         if (GUSvoice(wVSRVolRampControl) & 0x2000)
 113                             GUSvoice(wVSRVolRampControl) |= 0x8000;     /* volramp IRQ enabled? -> IRQ wait flag */
 114                         if (GUSvoice(wVSRVolRampControl) & 0x800)       /* loop enabled */
 115                         {
 116                             if (GUSvoice(wVSRVolRampControl) & 0x1000)  /* bidir. loop */
 117                             {
 118                                 GUSvoice(wVSRVolRampControl) ^= 0x4000; /* toggle dir */
 119                                 VolumeIncrement32 = -VolumeIncrement32;
 120                             }
 121                             else
 122                                 Volume32 = (GUSvoice(wVSRVolRampControl) & 0x4000) ? EndVol32 : StartVol32; /* unidir. loop ramp */
 123                         }
 124                         else
 125                         {
 126                             GUSvoice(wVSRVolRampControl) |= 0x100;
 127                             Volume32 =
 128                                 (GUSvoice(wVSRVolRampControl) & 0x4000) ? StartVol32 : EndVol32;
 129                         }
 130                     }
 131                 }
 132                 if ((GUSvoice(wVSRVolRampControl) & 0xa000) == 0xa000)  /* volramp IRQ set and enabled? */
 133                 {
 134                     GUSregd(voicevolrampirq) |= 1 << Voice;             /* set irq slot */
 135                 }
 136                 else
 137                 {
 138                     GUSregd(voicevolrampirq) &= (~(1 << Voice));        /* clear irq slot */
 139                     GUSvoice(wVSRVolRampControl) &= 0x7f00;
 140                 }
 141
 142                 if (!(GUSvoice(wVSRControl) & 0x100))
 143                 {
 144                     CurrPos += VoiceIncrement;
 145                     if ((GUSvoice(wVSRControl) & 0x4000) ? (CurrPos <= LoopStart) : (CurrPos >= LoopEnd)) /* playback boundary cross */
 146                     {
 147                         if (GUSvoice(wVSRControl) & 0x2000)
 148                             GUSvoice(wVSRControl) |= 0x8000;       /* voice IRQ enabled -> IRQ wait flag */
 149                         if (GUSvoice(wVSRControl) & 0x800)         /* loop enabled */
 150                         {
 151                             if (GUSvoice(wVSRControl) & 0x1000)    /* pingpong loop */
 152                             {
 153                                 GUSvoice(wVSRControl) ^= 0x4000;   /* toggle dir */
 154                                 VoiceIncrement = -VoiceIncrement;
 155                             }
 156                             else
 157                                 CurrPos = (GUSvoice(wVSRControl) & 0x4000) ? LoopEnd : LoopStart; /* unidir. loop */
 158                         }
 159                         else if (!(GUSvoice(wVSRVolRampControl) & 0x400))
 160                             GUSvoice(wVSRControl) |= 0x100;        /* loop disabled, rollover check */
 161                     }
 162                 }
 163                 if ((GUSvoice(wVSRControl) & 0xa000) == 0xa000)    /* wavetable IRQ set and enabled? */
 164                 {
 165                     GUSregd(voicewavetableirq) |= 1 << Voice;      /* set irq slot */
 166                 }
 167                 else
 168                 {
 169                     GUSregd(voicewavetableirq) &= (~(1 << Voice)); /* clear irq slot */
 170                     GUSvoice(wVSRControl) &= 0x7f00;
 171                 }
 172
 173                 /* mix samples into buffer */
 174                 *(bufferpos + 2 * sample)     += (int16_t) ((sample1 * PanningPos) >> 4);        /* right */
 175                 *(bufferpos + 2 * sample + 1) += (int16_t) ((sample1 * (15 - PanningPos)) >> 4); /* left */
 176             }
 177             /* write back voice and volume */
 178             GUSvoice(wVSRCurrVol)   = Volume32 / 32;
 179             GUSvoice(wVSRCurrPosHi) = CurrPos >> 16;
 180             GUSvoice(wVSRCurrPosLo) = CurrPos & 0xffff;
 181         }
 182         voiceptr += 16; /* next voice */
 183     }
 184 }
 185
 186 void gus_irqgen(GUSEmuState * state, unsigned int elapsed_time)
 187 /* time given in microseconds */
 188 {
 189     int             requestedIRQs = 0;
 190     uint8_t        *gusptr;
 191     gusptr = state->gusdatapos;
 192     if (GUSregb(TimerDataReg2x9) & 1) /* start timer 1 (80us decrement rate) */
 193     {
 194         unsigned int    timer1fraction = state->timer1fraction;
 195         int             newtimerirqs;
 196         newtimerirqs          = (elapsed_time + timer1fraction) / (80 * (256 - GUSregb(GUS46Counter1)));
 197         state->timer1fraction = (elapsed_time + timer1fraction) % (80 * (256 - GUSregb(GUS46Counter1)));
 198         if (newtimerirqs)
 199         {
 200             if (!(GUSregb(TimerDataReg2x9) & 0x40))
 201                 GUSregb(TimerStatus2x8) |= 0xc0; /* maskable bits */
 202             if (GUSregb(GUS45TimerCtrl) & 4)     /* timer1 irq enable */
 203             {
 204                 GUSregb(TimerStatus2x8) |= 4;    /* nonmaskable bit */
 205                 GUSregb(IRQStatReg2x6)  |= 4;    /* timer 1 irq pending */
 206                 GUSregw(TimerIRQs) += newtimerirqs;
 207                 requestedIRQs += newtimerirqs;
 208             }
 209         }
 210     }
 211     if (GUSregb(TimerDataReg2x9) & 2) /* start timer 2 (320us decrement rate) */
 212     {
 213         unsigned int timer2fraction = state->timer2fraction;
 214         int             newtimerirqs;
 215         newtimerirqs          = (elapsed_time + timer2fraction) / (320 * (256 - GUSregb(GUS47Counter2)));
 216         state->timer2fraction = (elapsed_time + timer2fraction) % (320 * (256 - GUSregb(GUS47Counter2)));
 217         if (newtimerirqs)
 218         {
 219             if (!(GUSregb(TimerDataReg2x9) & 0x20))
 220                 GUSregb(TimerStatus2x8) |= 0xa0; /* maskable bits */
 221             if (GUSregb(GUS45TimerCtrl) & 8)     /* timer2 irq enable */
 222             {
 223                 GUSregb(TimerStatus2x8) |= 2;    /* nonmaskable bit */
 224                 GUSregb(IRQStatReg2x6)  |= 8;    /* timer 2 irq pending */
 225                 GUSregw(TimerIRQs) += newtimerirqs;
 226                 requestedIRQs += newtimerirqs;
 227             }
 228         }
 229     }
 230     if (GUSregb(GUS4cReset) & 0x4) /* synth IRQ enable */
 231     {
 232         if (GUSregd(voicewavetableirq))
 233             GUSregb(IRQStatReg2x6) |= 0x20;
 234         if (GUSregd(voicevolrampirq))
 235             GUSregb(IRQStatReg2x6) |= 0x40;
 236     }
 237     if ((!requestedIRQs) && GUSregb(IRQStatReg2x6))
 238         requestedIRQs++;
 239     if (GUSregb(IRQStatReg2x6))
 240         GUSregw(BusyTimerIRQs) = GUS_irqrequest(state, state->gusirq, requestedIRQs);
 241 }