xref: /openbmc/qemu/hw/audio/gusemu_mixer.c (revision 5acc270a)
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)  (*(uint32_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) */
gus_mixvoices(GUSEmuState * state,unsigned int playback_freq,unsigned int numsamples,int16_t * bufferpos)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 
gus_irqgen(GUSEmuState * state,unsigned int elapsed_time)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 }
242