src/gb/audio.c (view raw)
1/* Copyright (c) 2013-2016 Jeffrey Pfau
2 *
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6#include "audio.h"
7
8#include "core/sync.h"
9#include "gb/gb.h"
10#include "gb/io.h"
11
12#define FRAME_CYCLES (DMG_LR35902_FREQUENCY >> 9)
13
14const uint32_t DMG_LR35902_FREQUENCY = 0x400000;
15static const int CLOCKS_PER_BLIP_FRAME = 0x1000;
16static const unsigned BLIP_BUFFER_SIZE = 0x4000;
17const int GB_AUDIO_VOLUME_MAX = 0x100;
18
19static void _writeDuty(struct GBAudioEnvelope* envelope, uint8_t value);
20static bool _writeSweep(struct GBAudioEnvelope* envelope, uint8_t value);
21static int32_t _updateSquareChannel(struct GBAudioSquareControl* envelope, int duty);
22static void _updateEnvelope(struct GBAudioEnvelope* envelope);
23static bool _updateSweep(struct GBAudioChannel1* ch, bool initial);
24static int32_t _updateChannel1(struct GBAudioChannel1* ch);
25static int32_t _updateChannel2(struct GBAudioChannel2* ch);
26static int32_t _updateChannel3(struct GBAudioChannel3* ch);
27static int32_t _updateChannel4(struct GBAudioChannel4* ch);
28static void _sample(struct GBAudio* audio, int32_t cycles);
29
30void GBAudioInit(struct GBAudio* audio, size_t samples, uint8_t* nr52) {
31 audio->samples = samples;
32 audio->left = blip_new(BLIP_BUFFER_SIZE);
33 audio->right = blip_new(BLIP_BUFFER_SIZE);
34 audio->clockRate = DMG_LR35902_FREQUENCY;
35 // Guess too large; we hang producing extra samples if we guess too low
36 blip_set_rates(audio->left, DMG_LR35902_FREQUENCY, 96000);
37 blip_set_rates(audio->right, DMG_LR35902_FREQUENCY, 96000);
38 audio->forceDisableCh[0] = false;
39 audio->forceDisableCh[1] = false;
40 audio->forceDisableCh[2] = false;
41 audio->forceDisableCh[3] = false;
42 audio->masterVolume = GB_AUDIO_VOLUME_MAX;
43 audio->nr52 = nr52;
44}
45
46void GBAudioDeinit(struct GBAudio* audio) {
47 blip_delete(audio->left);
48 blip_delete(audio->right);
49}
50
51void GBAudioReset(struct GBAudio* audio) {
52 audio->nextEvent = 0;
53 audio->nextCh1 = 0;
54 audio->nextCh2 = 0;
55 audio->nextCh3 = 0;
56 audio->nextCh4 = 0;
57 audio->ch1 = (struct GBAudioChannel1) { .envelope = { .dead = 2 } };
58 audio->ch2 = (struct GBAudioChannel2) { .envelope = { .dead = 2 } };
59 audio->ch3 = (struct GBAudioChannel3) { .bank = 0 };
60 audio->ch4 = (struct GBAudioChannel4) { .envelope = { .dead = 2 } };
61 audio->eventDiff = 0;
62 audio->nextFrame = 0;
63 audio->frame = 0;
64 audio->nextSample = 0;
65 audio->sampleInterval = 128;
66 audio->volumeRight = 0;
67 audio->volumeLeft = 0;
68 audio->ch1Right = false;
69 audio->ch2Right = false;
70 audio->ch3Right = false;
71 audio->ch4Right = false;
72 audio->ch1Left = false;
73 audio->ch2Left = false;
74 audio->ch3Left = false;
75 audio->ch4Left = false;
76 audio->playingCh1 = false;
77 audio->playingCh2 = false;
78 audio->playingCh3 = false;
79 audio->playingCh4 = false;
80}
81
82void GBAudioResizeBuffer(struct GBAudio* audio, size_t samples) {
83 mCoreSyncLockAudio(audio->p->sync);
84 audio->samples = samples;
85 blip_clear(audio->left);
86 blip_clear(audio->right);
87 audio->clock = 0;
88 mCoreSyncConsumeAudio(audio->p->sync);
89}
90
91void GBAudioWriteNR10(struct GBAudio* audio, uint8_t value) {
92 audio->ch1.shift = GBAudioRegisterSquareSweepGetShift(value);
93 bool oldDirection = audio->ch1.direction;
94 audio->ch1.direction = GBAudioRegisterSquareSweepGetDirection(value);
95 if (audio->ch1.sweepOccurred && oldDirection && !audio->ch1.direction) {
96 audio->playingCh1 = false;
97 *audio->nr52 &= ~0x0001;
98 }
99 audio->ch1.sweepOccurred = false;
100 audio->ch1.time = GBAudioRegisterSquareSweepGetTime(value);
101 if (!audio->ch1.time) {
102 audio->ch1.time = 8;
103 }
104}
105
106void GBAudioWriteNR11(struct GBAudio* audio, uint8_t value) {
107 _writeDuty(&audio->ch1.envelope, value);
108 audio->ch1.control.length = 64 - audio->ch1.envelope.length;
109}
110
111void GBAudioWriteNR12(struct GBAudio* audio, uint8_t value) {
112 if (!_writeSweep(&audio->ch1.envelope, value)) {
113 audio->playingCh1 = false;
114 *audio->nr52 &= ~0x0001;
115 }
116}
117
118void GBAudioWriteNR13(struct GBAudio* audio, uint8_t value) {
119 audio->ch1.realFrequency &= 0x700;
120 audio->ch1.realFrequency |= GBAudioRegisterControlGetFrequency(value);
121}
122
123void GBAudioWriteNR14(struct GBAudio* audio, uint8_t value) {
124 audio->ch1.realFrequency &= 0xFF;
125 audio->ch1.realFrequency |= GBAudioRegisterControlGetFrequency(value << 8);
126 bool wasStop = audio->ch1.control.stop;
127 audio->ch1.control.stop = GBAudioRegisterControlGetStop(value << 8);
128 if (!wasStop && audio->ch1.control.stop && audio->ch1.control.length && !(audio->frame & 1)) {
129 --audio->ch1.control.length;
130 if (audio->ch1.control.length == 0) {
131 audio->playingCh1 = false;
132 }
133 }
134 if (GBAudioRegisterControlIsRestart(value << 8)) {
135 if (audio->nextEvent == INT_MAX) {
136 audio->eventDiff = 0;
137 }
138 if (!audio->playingCh1) {
139 audio->nextCh1 = audio->eventDiff;
140 }
141 audio->playingCh1 = audio->ch1.envelope.initialVolume || audio->ch1.envelope.direction;
142 audio->ch1.envelope.currentVolume = audio->ch1.envelope.initialVolume;
143 if (audio->ch1.envelope.currentVolume > 0 && audio->ch1.envelope.stepTime) {
144 audio->ch1.envelope.dead = 0;
145 }
146 audio->ch1.control.frequency = audio->ch1.realFrequency;
147 audio->ch1.sweepStep = audio->ch1.time;
148 audio->ch1.sweepEnable = (audio->ch1.sweepStep != 8) || audio->ch1.shift;
149 audio->ch1.sweepOccurred = false;
150 if (audio->playingCh1 && audio->ch1.shift) {
151 audio->playingCh1 = _updateSweep(&audio->ch1, true);
152 }
153 if (!audio->ch1.control.length) {
154 audio->ch1.control.length = 64;
155 if (audio->ch1.control.stop && !(audio->frame & 1)) {
156 --audio->ch1.control.length;
157 }
158 }
159 audio->nextEvent = audio->eventDiff;
160 if (audio->p) {
161 // TODO: Don't need p
162 audio->p->cpu->nextEvent = audio->eventDiff;
163 }
164 }
165 *audio->nr52 &= ~0x0001;
166 *audio->nr52 |= audio->playingCh1;
167}
168
169void GBAudioWriteNR21(struct GBAudio* audio, uint8_t value) {
170 _writeDuty(&audio->ch2.envelope, value);
171 audio->ch2.control.length = 64 - audio->ch2.envelope.length;
172}
173
174void GBAudioWriteNR22(struct GBAudio* audio, uint8_t value) {
175 if (!_writeSweep(&audio->ch2.envelope, value)) {
176 audio->playingCh2 = false;
177 *audio->nr52 &= ~0x0002;
178 }
179}
180
181void GBAudioWriteNR23(struct GBAudio* audio, uint8_t value) {
182 audio->ch2.control.frequency &= 0x700;
183 audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value);
184}
185
186void GBAudioWriteNR24(struct GBAudio* audio, uint8_t value) {
187 audio->ch2.control.frequency &= 0xFF;
188 audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value << 8);
189 bool wasStop = audio->ch2.control.stop;
190 audio->ch2.control.stop = GBAudioRegisterControlGetStop(value << 8);
191 if (!wasStop && audio->ch2.control.stop && audio->ch2.control.length && !(audio->frame & 1)) {
192 --audio->ch2.control.length;
193 if (audio->ch2.control.length == 0) {
194 audio->playingCh2 = false;
195 }
196 }
197 if (GBAudioRegisterControlIsRestart(value << 8)) {
198 audio->playingCh2 = audio->ch2.envelope.initialVolume || audio->ch2.envelope.direction;
199 audio->ch2.envelope.currentVolume = audio->ch2.envelope.initialVolume;
200 if (audio->ch2.envelope.currentVolume > 0 && audio->ch2.envelope.stepTime) {
201 audio->ch2.envelope.dead = 0;
202 }
203 if (audio->nextEvent == INT_MAX) {
204 audio->eventDiff = 0;
205 }
206 if (!audio->playingCh2) {
207 audio->nextCh2 = audio->eventDiff;
208 }
209 if (!audio->ch2.control.length) {
210 audio->ch2.control.length = 64;
211 if (audio->ch2.control.stop && !(audio->frame & 1)) {
212 --audio->ch2.control.length;
213 }
214 }
215 audio->nextEvent = audio->eventDiff;
216 if (audio->p) {
217 // TODO: Don't need p
218 audio->p->cpu->nextEvent = audio->eventDiff;
219 }
220 }
221 *audio->nr52 &= ~0x0002;
222 *audio->nr52 |= audio->playingCh2 << 1;
223}
224
225void GBAudioWriteNR30(struct GBAudio* audio, uint8_t value) {
226 audio->ch3.enable = GBAudioRegisterBankGetEnable(value);
227 if (!audio->ch3.enable) {
228 audio->playingCh3 = false;
229 *audio->nr52 &= ~0x0004;
230 }
231}
232
233void GBAudioWriteNR31(struct GBAudio* audio, uint8_t value) {
234 audio->ch3.length = 256 - value;
235}
236
237void GBAudioWriteNR32(struct GBAudio* audio, uint8_t value) {
238 audio->ch3.volume = GBAudioRegisterBankVolumeGetVolumeGB(value);
239}
240
241void GBAudioWriteNR33(struct GBAudio* audio, uint8_t value) {
242 audio->ch3.rate &= 0x700;
243 audio->ch3.rate |= GBAudioRegisterControlGetRate(value);
244}
245
246void GBAudioWriteNR34(struct GBAudio* audio, uint8_t value) {
247 audio->ch3.rate &= 0xFF;
248 audio->ch3.rate |= GBAudioRegisterControlGetRate(value << 8);
249 bool wasStop = audio->ch3.stop;
250 audio->ch3.stop = GBAudioRegisterControlGetStop(value << 8);
251 if (!wasStop && audio->ch3.stop && audio->ch3.length && !(audio->frame & 1)) {
252 --audio->ch3.length;
253 if (audio->ch3.length == 0) {
254 audio->playingCh3 = false;
255 }
256 }
257 if (GBAudioRegisterControlIsRestart(value << 8)) {
258 audio->playingCh3 = audio->ch3.enable;
259 if (!audio->ch3.length) {
260 audio->ch3.length = 256;
261 if (audio->ch3.stop && !(audio->frame & 1)) {
262 --audio->ch3.length;
263 }
264 }
265 }
266 if (audio->playingCh3) {
267 if (audio->nextEvent == INT_MAX) {
268 audio->eventDiff = 0;
269 }
270 audio->nextCh3 = audio->eventDiff;
271 audio->nextEvent = audio->eventDiff;
272 if (audio->p) {
273 // TODO: Don't need p
274 audio->p->cpu->nextEvent = audio->eventDiff;
275 }
276 }
277 *audio->nr52 &= ~0x0004;
278 *audio->nr52 |= audio->playingCh3 << 2;
279}
280
281void GBAudioWriteNR41(struct GBAudio* audio, uint8_t value) {
282 _writeDuty(&audio->ch4.envelope, value);
283 audio->ch4.length = 64 - audio->ch4.envelope.length;
284}
285
286void GBAudioWriteNR42(struct GBAudio* audio, uint8_t value) {
287 if (!_writeSweep(&audio->ch4.envelope, value)) {
288 audio->playingCh4 = false;
289 *audio->nr52 &= ~0x0008;
290 }
291}
292
293void GBAudioWriteNR43(struct GBAudio* audio, uint8_t value) {
294 audio->ch4.ratio = GBAudioRegisterNoiseFeedbackGetRatio(value);
295 audio->ch4.frequency = GBAudioRegisterNoiseFeedbackGetFrequency(value);
296 audio->ch4.power = GBAudioRegisterNoiseFeedbackGetPower(value);
297}
298
299void GBAudioWriteNR44(struct GBAudio* audio, uint8_t value) {
300 bool wasStop = audio->ch4.stop;
301 audio->ch4.stop = GBAudioRegisterNoiseControlGetStop(value);
302 if (!wasStop && audio->ch4.stop && audio->ch4.length && !(audio->frame & 1)) {
303 --audio->ch4.length;
304 if (audio->ch4.length == 0) {
305 audio->playingCh4 = false;
306 }
307 }
308 if (GBAudioRegisterNoiseControlIsRestart(value)) {
309 audio->playingCh4 = audio->ch4.envelope.initialVolume || audio->ch4.envelope.direction;
310 audio->ch4.envelope.currentVolume = audio->ch4.envelope.initialVolume;
311 if (audio->ch4.envelope.currentVolume > 0 && audio->ch4.envelope.stepTime) {
312 audio->ch4.envelope.dead = 0;
313 }
314 if (audio->ch4.power) {
315 audio->ch4.lfsr = 0x40;
316 } else {
317 audio->ch4.lfsr = 0x4000;
318 }
319 if (audio->nextEvent == INT_MAX) {
320 audio->eventDiff = 0;
321 }
322 if (!audio->playingCh4) {
323 audio->nextCh4 = audio->eventDiff;
324 }
325 if (!audio->ch4.length) {
326 audio->ch4.length = 64;
327 if (audio->ch4.stop && !(audio->frame & 1)) {
328 --audio->ch4.length;
329 }
330 }
331 audio->nextEvent = audio->eventDiff;
332 if (audio->p) {
333 // TODO: Don't need p
334 audio->p->cpu->nextEvent = audio->eventDiff;
335 }
336 }
337 *audio->nr52 &= ~0x0008;
338 *audio->nr52 |= audio->playingCh4 << 3;
339}
340
341void GBAudioWriteNR50(struct GBAudio* audio, uint8_t value) {
342 audio->volumeRight = GBRegisterNR50GetVolumeRight(value);
343 audio->volumeLeft = GBRegisterNR50GetVolumeLeft(value);
344}
345
346void GBAudioWriteNR51(struct GBAudio* audio, uint8_t value) {
347 audio->ch1Right = GBRegisterNR51GetCh1Right(value);
348 audio->ch2Right = GBRegisterNR51GetCh2Right(value);
349 audio->ch3Right = GBRegisterNR51GetCh3Right(value);
350 audio->ch4Right = GBRegisterNR51GetCh4Right(value);
351 audio->ch1Left = GBRegisterNR51GetCh1Left(value);
352 audio->ch2Left = GBRegisterNR51GetCh2Left(value);
353 audio->ch3Left = GBRegisterNR51GetCh3Left(value);
354 audio->ch4Left = GBRegisterNR51GetCh4Left(value);
355}
356
357void GBAudioWriteNR52(struct GBAudio* audio, uint8_t value) {
358 bool wasEnable = audio->enable;
359 audio->enable = GBAudioEnableGetEnable(value);
360 if (!audio->enable) {
361 audio->playingCh1 = 0;
362 audio->playingCh2 = 0;
363 audio->playingCh3 = 0;
364 audio->playingCh4 = 0;
365 GBAudioWriteNR10(audio, 0);
366 GBAudioWriteNR11(audio, 0);
367 GBAudioWriteNR12(audio, 0);
368 GBAudioWriteNR13(audio, 0);
369 GBAudioWriteNR14(audio, 0);
370 GBAudioWriteNR21(audio, 0);
371 GBAudioWriteNR22(audio, 0);
372 GBAudioWriteNR23(audio, 0);
373 GBAudioWriteNR24(audio, 0);
374 GBAudioWriteNR30(audio, 0);
375 GBAudioWriteNR31(audio, 0);
376 GBAudioWriteNR32(audio, 0);
377 GBAudioWriteNR33(audio, 0);
378 GBAudioWriteNR34(audio, 0);
379 // Don't write to NR41
380 GBAudioWriteNR42(audio, 0);
381 GBAudioWriteNR43(audio, 0);
382 GBAudioWriteNR44(audio, 0);
383 GBAudioWriteNR50(audio, 0);
384 GBAudioWriteNR51(audio, 0);
385 if (audio->p) {
386 audio->p->memory.io[REG_NR10] = 0;
387 audio->p->memory.io[REG_NR11] = 0;
388 audio->p->memory.io[REG_NR12] = 0;
389 audio->p->memory.io[REG_NR13] = 0;
390 audio->p->memory.io[REG_NR14] = 0;
391 audio->p->memory.io[REG_NR21] = 0;
392 audio->p->memory.io[REG_NR22] = 0;
393 audio->p->memory.io[REG_NR23] = 0;
394 audio->p->memory.io[REG_NR24] = 0;
395 audio->p->memory.io[REG_NR30] = 0;
396 audio->p->memory.io[REG_NR31] = 0;
397 audio->p->memory.io[REG_NR32] = 0;
398 audio->p->memory.io[REG_NR33] = 0;
399 audio->p->memory.io[REG_NR34] = 0;
400 audio->p->memory.io[REG_NR42] = 0;
401 audio->p->memory.io[REG_NR43] = 0;
402 audio->p->memory.io[REG_NR44] = 0;
403 audio->p->memory.io[REG_NR50] = 0;
404 audio->p->memory.io[REG_NR51] = 0;
405 }
406 *audio->nr52 &= ~0x000F;
407 } else if (!wasEnable) {
408 audio->frame = 7;
409 }
410}
411
412int32_t GBAudioProcessEvents(struct GBAudio* audio, int32_t cycles) {
413 if (audio->nextEvent == INT_MAX) {
414 return INT_MAX;
415 }
416 audio->nextEvent -= cycles;
417 audio->eventDiff += cycles;
418 while (audio->nextEvent <= 0) {
419 audio->nextEvent = INT_MAX;
420 if (audio->enable) {
421 audio->nextFrame -= audio->eventDiff;
422 int frame = -1;
423 if (audio->nextFrame <= 0) {
424 frame = (audio->frame + 1) & 7;
425 audio->frame = frame;
426 audio->nextFrame += FRAME_CYCLES;
427 if (audio->nextFrame < audio->nextEvent) {
428 audio->nextEvent = audio->nextFrame;
429 }
430 }
431
432 if (audio->playingCh1) {
433 audio->nextCh1 -= audio->eventDiff;
434 if (!audio->ch1.envelope.dead && frame == 7) {
435 --audio->ch1.envelope.nextStep;
436 if (audio->ch1.envelope.nextStep == 0) {
437 int8_t sample = audio->ch1.control.hi * 0x10 - 0x8;
438 _updateEnvelope(&audio->ch1.envelope);
439 audio->ch1.sample = sample * audio->ch1.envelope.currentVolume;
440 }
441 }
442
443 if (audio->ch1.sweepEnable && (frame & 3) == 2) {
444 --audio->ch1.sweepStep;
445 if (audio->ch1.sweepStep == 0) {
446 audio->playingCh1 = _updateSweep(&audio->ch1, false);
447 }
448 }
449
450 if (audio->ch1.envelope.dead != 2) {
451 if (audio->nextCh1 <= 0) {
452 audio->nextCh1 += _updateChannel1(&audio->ch1);
453 }
454 if (audio->nextCh1 < audio->nextEvent) {
455 audio->nextEvent = audio->nextCh1;
456 }
457 }
458 }
459
460 if (audio->ch1.control.length && audio->ch1.control.stop && !(frame & 1)) {
461 --audio->ch1.control.length;
462 if (audio->ch1.control.length == 0) {
463 audio->playingCh1 = 0;
464 }
465 }
466
467 if (audio->playingCh2) {
468 audio->nextCh2 -= audio->eventDiff;
469 if (!audio->ch2.envelope.dead && frame == 7) {
470 --audio->ch2.envelope.nextStep;
471 if (audio->ch2.envelope.nextStep == 0) {
472 int8_t sample = audio->ch2.control.hi * 0x10 - 0x8;
473 _updateEnvelope(&audio->ch2.envelope);
474 audio->ch2.sample = sample * audio->ch2.envelope.currentVolume;
475 }
476 }
477
478 if (audio->ch2.envelope.dead != 2) {
479 if (audio->nextCh2 <= 0) {
480 audio->nextCh2 += _updateChannel2(&audio->ch2);
481 }
482 if (audio->nextCh2 < audio->nextEvent) {
483 audio->nextEvent = audio->nextCh2;
484 }
485 }
486 }
487
488 if (audio->ch2.control.length && audio->ch2.control.stop && !(frame & 1)) {
489 --audio->ch2.control.length;
490 if (audio->ch2.control.length == 0) {
491 audio->playingCh2 = 0;
492 }
493 }
494
495 if (audio->playingCh3) {
496 audio->nextCh3 -= audio->eventDiff;
497 if (audio->nextCh3 <= 0) {
498 audio->nextCh3 += _updateChannel3(&audio->ch3);
499 }
500 if (audio->nextCh3 < audio->nextEvent) {
501 audio->nextEvent = audio->nextCh3;
502 }
503 }
504
505 if (audio->ch3.length && audio->ch3.stop && !(frame & 1)) {
506 --audio->ch3.length;
507 if (audio->ch3.length == 0) {
508 audio->playingCh3 = 0;
509 }
510 }
511
512 if (audio->playingCh4) {
513 audio->nextCh4 -= audio->eventDiff;
514 if (!audio->ch4.envelope.dead && frame == 7) {
515 --audio->ch4.envelope.nextStep;
516 if (audio->ch4.envelope.nextStep == 0) {
517 int8_t sample = (audio->ch4.sample >> 31) * 0x8;
518 _updateEnvelope(&audio->ch4.envelope);
519 audio->ch4.sample = sample * audio->ch4.envelope.currentVolume;
520 }
521 }
522
523 if (audio->ch4.envelope.dead != 2) {
524 if (audio->nextCh4 <= 0) {
525 int32_t timing = _updateChannel4(&audio->ch4);
526 if (audio->nextCh4 < -timing) {
527 int32_t bound = timing * 16;
528 // Perform negative modulo to cap to 16 iterations
529 audio->nextCh4 = bound - (audio->nextCh4 - 1) % bound - 1;
530 }
531 audio->nextCh4 += timing;
532 }
533 if (audio->nextCh4 < audio->nextEvent) {
534 audio->nextEvent = audio->nextCh4;
535 }
536 }
537 }
538
539 if (audio->ch4.length && audio->ch4.stop && !(frame & 1)) {
540 --audio->ch4.length;
541 if (audio->ch4.length == 0) {
542 audio->playingCh4 = 0;
543 }
544 }
545 }
546
547 *audio->nr52 &= ~0x000F;
548 *audio->nr52 |= audio->playingCh1;
549 *audio->nr52 |= audio->playingCh2 << 1;
550 *audio->nr52 |= audio->playingCh3 << 2;
551 *audio->nr52 |= audio->playingCh4 << 3;
552
553 if (audio->p) {
554 audio->nextSample -= audio->eventDiff;
555 if (audio->nextSample <= 0) {
556 _sample(audio, audio->sampleInterval);
557 audio->nextSample += audio->sampleInterval;
558 }
559
560 if (audio->nextSample < audio->nextEvent) {
561 audio->nextEvent = audio->nextSample;
562 }
563 }
564 audio->eventDiff = 0;
565 }
566 return audio->nextEvent;
567}
568
569void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right) {
570 int sampleLeft = 0;
571 int sampleRight = 0;
572
573 if (audio->playingCh1 && !audio->forceDisableCh[0]) {
574 if (audio->ch1Left) {
575 sampleLeft += audio->ch1.sample;
576 }
577
578 if (audio->ch1Right) {
579 sampleRight += audio->ch1.sample;
580 }
581 }
582
583 if (audio->playingCh2 && !audio->forceDisableCh[1]) {
584 if (audio->ch2Left) {
585 sampleLeft += audio->ch2.sample;
586 }
587
588 if (audio->ch2Right) {
589 sampleRight += audio->ch2.sample;
590 }
591 }
592
593 if (audio->playingCh3 && !audio->forceDisableCh[2]) {
594 if (audio->ch3Left) {
595 sampleLeft += audio->ch3.sample;
596 }
597
598 if (audio->ch3Right) {
599 sampleRight += audio->ch3.sample;
600 }
601 }
602
603 if (audio->playingCh4 && !audio->forceDisableCh[3]) {
604 if (audio->ch4Left) {
605 sampleLeft += audio->ch4.sample;
606 }
607
608 if (audio->ch4Right) {
609 sampleRight += audio->ch4.sample;
610 }
611 }
612
613 *left = sampleLeft * (1 + audio->volumeLeft);
614 *right = sampleRight * (1 + audio->volumeRight);
615}
616
617void _sample(struct GBAudio* audio, int32_t cycles) {
618 int16_t sampleLeft = 0;
619 int16_t sampleRight = 0;
620 GBAudioSamplePSG(audio, &sampleLeft, &sampleRight);
621 sampleLeft = (sampleLeft * audio->masterVolume) >> 6;
622 sampleRight = (sampleRight * audio->masterVolume) >> 6;
623
624 mCoreSyncLockAudio(audio->p->sync);
625 unsigned produced;
626 if ((size_t) blip_samples_avail(audio->left) < audio->samples) {
627 blip_add_delta(audio->left, audio->clock, sampleLeft - audio->lastLeft);
628 blip_add_delta(audio->right, audio->clock, sampleRight - audio->lastRight);
629 audio->lastLeft = sampleLeft;
630 audio->lastRight = sampleRight;
631 audio->clock += cycles;
632 if (audio->clock >= CLOCKS_PER_BLIP_FRAME) {
633 blip_end_frame(audio->left, audio->clock);
634 blip_end_frame(audio->right, audio->clock);
635 audio->clock -= CLOCKS_PER_BLIP_FRAME;
636 }
637 }
638 produced = blip_samples_avail(audio->left);
639 bool wait = produced >= audio->samples;
640 mCoreSyncProduceAudio(audio->p->sync, wait);
641 // TODO: Put AVStream back
642}
643
644void _writeDuty(struct GBAudioEnvelope* envelope, uint8_t value) {
645 envelope->length = GBAudioRegisterDutyGetLength(value);
646 envelope->duty = GBAudioRegisterDutyGetDuty(value);
647}
648
649bool _writeSweep(struct GBAudioEnvelope* envelope, uint8_t value) {
650 envelope->stepTime = GBAudioRegisterSweepGetStepTime(value);
651 envelope->direction = GBAudioRegisterSweepGetDirection(value);
652 envelope->initialVolume = GBAudioRegisterSweepGetInitialVolume(value);
653 if (envelope->stepTime == 0) {
654 envelope->dead = envelope->currentVolume ? 1 : 2;
655 } else if (!envelope->direction && !envelope->currentVolume) {
656 envelope->dead = 2;
657 } else if (envelope->direction && envelope->currentVolume == 0xF) {
658 envelope->dead = 1;
659 } else {
660 envelope->dead = 0;
661 }
662 envelope->nextStep = envelope->stepTime;
663 return envelope->initialVolume || envelope->direction;
664}
665
666static int32_t _updateSquareChannel(struct GBAudioSquareControl* control, int duty) {
667 control->hi = !control->hi;
668 int period = 4 * (2048 - control->frequency);
669 switch (duty) {
670 case 0:
671 return control->hi ? period : period * 7;
672 case 1:
673 return control->hi ? period * 2 : period * 6;
674 case 2:
675 return period * 4;
676 case 3:
677 return control->hi ? period * 6 : period * 2;
678 default:
679 // This should never be hit
680 return period * 4;
681 }
682}
683
684static void _updateEnvelope(struct GBAudioEnvelope* envelope) {
685 if (envelope->direction) {
686 ++envelope->currentVolume;
687 } else {
688 --envelope->currentVolume;
689 }
690 if (envelope->currentVolume >= 15) {
691 envelope->currentVolume = 15;
692 envelope->dead = 1;
693 } else if (envelope->currentVolume <= 0) {
694 envelope->currentVolume = 0;
695 envelope->dead = 2;
696 } else {
697 envelope->nextStep = envelope->stepTime;
698 }
699}
700
701static bool _updateSweep(struct GBAudioChannel1* ch, bool initial) {
702 if (initial || ch->time != 8) {
703 int frequency = ch->control.frequency;
704 if (ch->direction) {
705 frequency -= frequency >> ch->shift;
706 if (!initial && frequency >= 0) {
707 ch->control.frequency = frequency;
708 ch->realFrequency = frequency;
709 }
710 } else {
711 frequency += frequency >> ch->shift;
712 if (frequency < 2048) {
713 if (!initial && ch->shift) {
714 ch->control.frequency = frequency;
715 if (!_updateSweep(ch, true)) {
716 return false;
717 }
718 ch->realFrequency = frequency;
719 }
720 } else {
721 return false;
722 }
723 }
724 ch->sweepOccurred = true;
725 }
726 ch->sweepStep = ch->time;
727 return true;
728}
729
730static int32_t _updateChannel1(struct GBAudioChannel1* ch) {
731 int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
732 ch->sample = ch->control.hi * 0x10 - 0x8;
733 ch->sample *= ch->envelope.currentVolume;
734 return timing;
735}
736
737static int32_t _updateChannel2(struct GBAudioChannel2* ch) {
738 int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
739 ch->sample = ch->control.hi * 0x10 - 0x8;
740 ch->sample *= ch->envelope.currentVolume;
741 return timing;
742}
743
744static int32_t _updateChannel3(struct GBAudioChannel3* ch) {
745 int i;
746 int start;
747 int end;
748 int volume;
749 switch (ch->volume) {
750 case 0:
751 volume = 0;
752 break;
753 case 1:
754 volume = 4;
755 break;
756 case 2:
757 volume = 2;
758 break;
759 case 3:
760 volume = 1;
761 break;
762 default:
763 volume = 3;
764 break;
765 }
766 if (ch->size) {
767 start = 7;
768 end = 0;
769 } else if (ch->bank) {
770 start = 7;
771 end = 4;
772 } else {
773 start = 3;
774 end = 0;
775 }
776 uint32_t bitsCarry = ch->wavedata[end] & 0x000000F0;
777 uint32_t bits;
778 for (i = start; i >= end; --i) {
779 bits = ch->wavedata[i] & 0x000000F0;
780 ch->wavedata[i] = ((ch->wavedata[i] & 0x0F0F0F0F) << 4) | ((ch->wavedata[i] & 0xF0F0F000) >> 12);
781 ch->wavedata[i] |= bitsCarry << 20;
782 bitsCarry = bits;
783 }
784 ch->sample = bitsCarry >> 4;
785 ch->sample -= 8;
786 ch->sample *= volume * 4;
787 return 2 * (2048 - ch->rate);
788}
789
790static int32_t _updateChannel4(struct GBAudioChannel4* ch) {
791 int lsb = ch->lfsr & 1;
792 ch->sample = lsb * 0x10 - 0x8;
793 ch->sample *= ch->envelope.currentVolume;
794 ch->lfsr >>= 1;
795 ch->lfsr ^= (lsb * 0x60) << (ch->power ? 0 : 8);
796 int timing = ch->ratio ? 2 * ch->ratio : 1;
797 timing <<= ch->frequency;
798 timing *= 8;
799 return timing;
800}