1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
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,
short *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) += (short) ((sample1 * PanningPos) >> 4); /* right */
*(bufferpos + 2 * sample + 1) += (short) ((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);
}
|
