Annotation of qemu/hw/gusemu_mixer.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * GUSEMU32 - mixing engine (similar to Interwave GF1 compatibility)
                      3:  *
                      4:  * Copyright (C) 2000-2007 Tibor "TS" Sch├╝tz
                      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: }

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