xref: /illumos-kvm-cmd/hw/gusemu_mixer.c (revision 68396ea9)
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) */
gus_mixvoices(GUSEmuState * state,unsigned int playback_freq,unsigned int numsamples,GUSsample * bufferpos)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 
gus_irqgen(GUSEmuState * state,unsigned int elapsed_time)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