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, enum GBAudioStyle style);
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, enum GBAudioStyle style) {
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 audio->style = style;
45}
46
47void GBAudioDeinit(struct GBAudio* audio) {
48 blip_delete(audio->left);
49 blip_delete(audio->right);
50}
51
52void GBAudioReset(struct GBAudio* audio) {
53 audio->nextEvent = 0;
54 audio->nextCh1 = 0;
55 audio->nextCh2 = 0;
56 audio->nextCh3 = 0;
57 audio->nextCh4 = 0;
58 audio->ch1 = (struct GBAudioChannel1) { .envelope = { .dead = 2 } };
59 audio->ch2 = (struct GBAudioChannel2) { .envelope = { .dead = 2 } };
60 audio->ch3 = (struct GBAudioChannel3) { .bank = 0 };
61 audio->ch4 = (struct GBAudioChannel4) { .envelope = { .dead = 2 } };
62 audio->eventDiff = 0;
63 audio->nextFrame = 0;
64 audio->frame = 0;
65 audio->nextSample = 0;
66 audio->sampleInterval = 128;
67 audio->volumeRight = 0;
68 audio->volumeLeft = 0;
69 audio->ch1Right = false;
70 audio->ch2Right = false;
71 audio->ch3Right = false;
72 audio->ch4Right = false;
73 audio->ch1Left = false;
74 audio->ch2Left = false;
75 audio->ch3Left = false;
76 audio->ch4Left = false;
77 audio->playingCh1 = false;
78 audio->playingCh2 = false;
79 audio->playingCh3 = false;
80 audio->playingCh4 = false;
81}
82
83void GBAudioResizeBuffer(struct GBAudio* audio, size_t samples) {
84 mCoreSyncLockAudio(audio->p->sync);
85 audio->samples = samples;
86 blip_clear(audio->left);
87 blip_clear(audio->right);
88 audio->clock = 0;
89 mCoreSyncConsumeAudio(audio->p->sync);
90}
91
92void GBAudioWriteNR10(struct GBAudio* audio, uint8_t value) {
93 audio->ch1.shift = GBAudioRegisterSquareSweepGetShift(value);
94 bool oldDirection = audio->ch1.direction;
95 audio->ch1.direction = GBAudioRegisterSquareSweepGetDirection(value);
96 if (audio->ch1.sweepOccurred && oldDirection && !audio->ch1.direction) {
97 audio->playingCh1 = false;
98 *audio->nr52 &= ~0x0001;
99 }
100 audio->ch1.sweepOccurred = false;
101 audio->ch1.time = GBAudioRegisterSquareSweepGetTime(value);
102 if (!audio->ch1.time) {
103 audio->ch1.time = 8;
104 }
105}
106
107void GBAudioWriteNR11(struct GBAudio* audio, uint8_t value) {
108 _writeDuty(&audio->ch1.envelope, value);
109 audio->ch1.control.length = 64 - audio->ch1.envelope.length;
110}
111
112void GBAudioWriteNR12(struct GBAudio* audio, uint8_t value) {
113 if (!_writeSweep(&audio->ch1.envelope, value)) {
114 audio->playingCh1 = false;
115 *audio->nr52 &= ~0x0001;
116 }
117}
118
119void GBAudioWriteNR13(struct GBAudio* audio, uint8_t value) {
120 audio->ch1.realFrequency &= 0x700;
121 audio->ch1.realFrequency |= GBAudioRegisterControlGetFrequency(value);
122}
123
124void GBAudioWriteNR14(struct GBAudio* audio, uint8_t value) {
125 audio->ch1.realFrequency &= 0xFF;
126 audio->ch1.realFrequency |= GBAudioRegisterControlGetFrequency(value << 8);
127 bool wasStop = audio->ch1.control.stop;
128 audio->ch1.control.stop = GBAudioRegisterControlGetStop(value << 8);
129 if (!wasStop && audio->ch1.control.stop && audio->ch1.control.length && !(audio->frame & 1)) {
130 --audio->ch1.control.length;
131 if (audio->ch1.control.length == 0) {
132 audio->playingCh1 = false;
133 }
134 }
135 if (GBAudioRegisterControlIsRestart(value << 8)) {
136 if (audio->nextEvent == INT_MAX) {
137 audio->eventDiff = 0;
138 }
139 if (!audio->playingCh1) {
140 audio->nextCh1 = audio->eventDiff;
141 }
142 audio->playingCh1 = audio->ch1.envelope.initialVolume || audio->ch1.envelope.direction;
143 audio->ch1.envelope.currentVolume = audio->ch1.envelope.initialVolume;
144 if (audio->ch1.envelope.currentVolume > 0 && audio->ch1.envelope.stepTime) {
145 audio->ch1.envelope.dead = 0;
146 }
147 audio->ch1.control.frequency = audio->ch1.realFrequency;
148 audio->ch1.sweepStep = audio->ch1.time;
149 audio->ch1.sweepEnable = (audio->ch1.sweepStep != 8) || audio->ch1.shift;
150 audio->ch1.sweepOccurred = false;
151 if (audio->playingCh1 && audio->ch1.shift) {
152 audio->playingCh1 = _updateSweep(&audio->ch1, true);
153 }
154 if (!audio->ch1.control.length) {
155 audio->ch1.control.length = 64;
156 if (audio->ch1.control.stop && !(audio->frame & 1)) {
157 --audio->ch1.control.length;
158 }
159 }
160 audio->nextEvent = audio->p->cpu->cycles;
161 if (audio->p) {
162 // TODO: Don't need p
163 audio->p->cpu->nextEvent = audio->nextEvent;
164 }
165 }
166 *audio->nr52 &= ~0x0001;
167 *audio->nr52 |= audio->playingCh1;
168}
169
170void GBAudioWriteNR21(struct GBAudio* audio, uint8_t value) {
171 _writeDuty(&audio->ch2.envelope, value);
172 audio->ch2.control.length = 64 - audio->ch2.envelope.length;
173}
174
175void GBAudioWriteNR22(struct GBAudio* audio, uint8_t value) {
176 if (!_writeSweep(&audio->ch2.envelope, value)) {
177 audio->playingCh2 = false;
178 *audio->nr52 &= ~0x0002;
179 }
180}
181
182void GBAudioWriteNR23(struct GBAudio* audio, uint8_t value) {
183 audio->ch2.control.frequency &= 0x700;
184 audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value);
185}
186
187void GBAudioWriteNR24(struct GBAudio* audio, uint8_t value) {
188 audio->ch2.control.frequency &= 0xFF;
189 audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value << 8);
190 bool wasStop = audio->ch2.control.stop;
191 audio->ch2.control.stop = GBAudioRegisterControlGetStop(value << 8);
192 if (!wasStop && audio->ch2.control.stop && audio->ch2.control.length && !(audio->frame & 1)) {
193 --audio->ch2.control.length;
194 if (audio->ch2.control.length == 0) {
195 audio->playingCh2 = false;
196 }
197 }
198 if (GBAudioRegisterControlIsRestart(value << 8)) {
199 audio->playingCh2 = audio->ch2.envelope.initialVolume || audio->ch2.envelope.direction;
200 audio->ch2.envelope.currentVolume = audio->ch2.envelope.initialVolume;
201 if (audio->ch2.envelope.currentVolume > 0 && audio->ch2.envelope.stepTime) {
202 audio->ch2.envelope.dead = 0;
203 }
204 if (audio->nextEvent == INT_MAX) {
205 audio->eventDiff = 0;
206 }
207 if (!audio->playingCh2) {
208 audio->nextCh2 = audio->eventDiff;
209 }
210 if (!audio->ch2.control.length) {
211 audio->ch2.control.length = 64;
212 if (audio->ch2.control.stop && !(audio->frame & 1)) {
213 --audio->ch2.control.length;
214 }
215 }
216 audio->nextEvent = audio->p->cpu->cycles;
217 if (audio->p) {
218 // TODO: Don't need p
219 audio->p->cpu->nextEvent = audio->nextEvent;
220 }
221 }
222 *audio->nr52 &= ~0x0002;
223 *audio->nr52 |= audio->playingCh2 << 1;
224}
225
226void GBAudioWriteNR30(struct GBAudio* audio, uint8_t value) {
227 audio->ch3.enable = GBAudioRegisterBankGetEnable(value);
228 if (!audio->ch3.enable) {
229 audio->playingCh3 = false;
230 *audio->nr52 &= ~0x0004;
231 }
232}
233
234void GBAudioWriteNR31(struct GBAudio* audio, uint8_t value) {
235 audio->ch3.length = 256 - value;
236}
237
238void GBAudioWriteNR32(struct GBAudio* audio, uint8_t value) {
239 audio->ch3.volume = GBAudioRegisterBankVolumeGetVolumeGB(value);
240}
241
242void GBAudioWriteNR33(struct GBAudio* audio, uint8_t value) {
243 audio->ch3.rate &= 0x700;
244 audio->ch3.rate |= GBAudioRegisterControlGetRate(value);
245}
246
247void GBAudioWriteNR34(struct GBAudio* audio, uint8_t value) {
248 audio->ch3.rate &= 0xFF;
249 audio->ch3.rate |= GBAudioRegisterControlGetRate(value << 8);
250 bool wasStop = audio->ch3.stop;
251 audio->ch3.stop = GBAudioRegisterControlGetStop(value << 8);
252 if (!wasStop && audio->ch3.stop && audio->ch3.length && !(audio->frame & 1)) {
253 --audio->ch3.length;
254 if (audio->ch3.length == 0) {
255 audio->playingCh3 = false;
256 }
257 }
258 bool wasEnable = audio->playingCh3;
259 if (GBAudioRegisterControlIsRestart(value << 8)) {
260 audio->playingCh3 = audio->ch3.enable;
261 if (!audio->ch3.length) {
262 audio->ch3.length = 256;
263 if (audio->ch3.stop && !(audio->frame & 1)) {
264 --audio->ch3.length;
265 }
266 }
267
268 if (audio->style == GB_AUDIO_DMG && wasEnable && audio->playingCh3 && audio->ch3.readable) {
269 if (audio->ch3.window < 8) {
270 audio->ch3.wavedata8[0] = audio->ch3.wavedata8[audio->ch3.window >> 1];
271 } else {
272 audio->ch3.wavedata8[0] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3)];
273 audio->ch3.wavedata8[1] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 1];
274 audio->ch3.wavedata8[2] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 2];
275 audio->ch3.wavedata8[3] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 3];
276 }
277 }
278 audio->ch3.window = 0;
279 }
280 if (audio->playingCh3) {
281 if (audio->nextEvent == INT_MAX) {
282 audio->eventDiff = 0;
283 }
284 audio->nextCh3 = audio->eventDiff + audio->p->cpu->cycles + 2 + 2 * (2048 - audio->ch3.rate);
285 audio->ch3.readable = false;
286 audio->nextEvent = audio->p->cpu->cycles;
287 if (audio->p) {
288 // TODO: Don't need p
289 audio->p->cpu->nextEvent = audio->nextEvent;
290 }
291 }
292 *audio->nr52 &= ~0x0004;
293 *audio->nr52 |= audio->playingCh3 << 2;
294}
295
296void GBAudioWriteNR41(struct GBAudio* audio, uint8_t value) {
297 _writeDuty(&audio->ch4.envelope, value);
298 audio->ch4.length = 64 - audio->ch4.envelope.length;
299}
300
301void GBAudioWriteNR42(struct GBAudio* audio, uint8_t value) {
302 if (!_writeSweep(&audio->ch4.envelope, value)) {
303 audio->playingCh4 = false;
304 *audio->nr52 &= ~0x0008;
305 }
306}
307
308void GBAudioWriteNR43(struct GBAudio* audio, uint8_t value) {
309 audio->ch4.ratio = GBAudioRegisterNoiseFeedbackGetRatio(value);
310 audio->ch4.frequency = GBAudioRegisterNoiseFeedbackGetFrequency(value);
311 audio->ch4.power = GBAudioRegisterNoiseFeedbackGetPower(value);
312}
313
314void GBAudioWriteNR44(struct GBAudio* audio, uint8_t value) {
315 bool wasStop = audio->ch4.stop;
316 audio->ch4.stop = GBAudioRegisterNoiseControlGetStop(value);
317 if (!wasStop && audio->ch4.stop && audio->ch4.length && !(audio->frame & 1)) {
318 --audio->ch4.length;
319 if (audio->ch4.length == 0) {
320 audio->playingCh4 = false;
321 }
322 }
323 if (GBAudioRegisterNoiseControlIsRestart(value)) {
324 audio->playingCh4 = audio->ch4.envelope.initialVolume || audio->ch4.envelope.direction;
325 audio->ch4.envelope.currentVolume = audio->ch4.envelope.initialVolume;
326 if (audio->ch4.envelope.currentVolume > 0 && audio->ch4.envelope.stepTime) {
327 audio->ch4.envelope.dead = 0;
328 }
329 if (audio->ch4.power) {
330 audio->ch4.lfsr = 0x40;
331 } else {
332 audio->ch4.lfsr = 0x4000;
333 }
334 if (audio->nextEvent == INT_MAX) {
335 audio->eventDiff = 0;
336 }
337 if (!audio->playingCh4) {
338 audio->nextCh4 = audio->eventDiff;
339 }
340 if (!audio->ch4.length) {
341 audio->ch4.length = 64;
342 if (audio->ch4.stop && !(audio->frame & 1)) {
343 --audio->ch4.length;
344 }
345 }
346 audio->nextEvent = audio->p->cpu->cycles;
347 if (audio->p) {
348 // TODO: Don't need p
349 audio->p->cpu->nextEvent = audio->nextEvent;
350 }
351 }
352 *audio->nr52 &= ~0x0008;
353 *audio->nr52 |= audio->playingCh4 << 3;
354}
355
356void GBAudioWriteNR50(struct GBAudio* audio, uint8_t value) {
357 audio->volumeRight = GBRegisterNR50GetVolumeRight(value);
358 audio->volumeLeft = GBRegisterNR50GetVolumeLeft(value);
359}
360
361void GBAudioWriteNR51(struct GBAudio* audio, uint8_t value) {
362 audio->ch1Right = GBRegisterNR51GetCh1Right(value);
363 audio->ch2Right = GBRegisterNR51GetCh2Right(value);
364 audio->ch3Right = GBRegisterNR51GetCh3Right(value);
365 audio->ch4Right = GBRegisterNR51GetCh4Right(value);
366 audio->ch1Left = GBRegisterNR51GetCh1Left(value);
367 audio->ch2Left = GBRegisterNR51GetCh2Left(value);
368 audio->ch3Left = GBRegisterNR51GetCh3Left(value);
369 audio->ch4Left = GBRegisterNR51GetCh4Left(value);
370}
371
372void GBAudioWriteNR52(struct GBAudio* audio, uint8_t value) {
373 bool wasEnable = audio->enable;
374 audio->enable = GBAudioEnableGetEnable(value);
375 if (!audio->enable) {
376 audio->playingCh1 = 0;
377 audio->playingCh2 = 0;
378 audio->playingCh3 = 0;
379 audio->playingCh4 = 0;
380 GBAudioWriteNR10(audio, 0);
381 GBAudioWriteNR11(audio, 0);
382 GBAudioWriteNR12(audio, 0);
383 GBAudioWriteNR13(audio, 0);
384 GBAudioWriteNR14(audio, 0);
385 GBAudioWriteNR21(audio, 0);
386 GBAudioWriteNR22(audio, 0);
387 GBAudioWriteNR23(audio, 0);
388 GBAudioWriteNR24(audio, 0);
389 GBAudioWriteNR30(audio, 0);
390 GBAudioWriteNR31(audio, 0);
391 GBAudioWriteNR32(audio, 0);
392 GBAudioWriteNR33(audio, 0);
393 GBAudioWriteNR34(audio, 0);
394 // Don't write to NR41
395 GBAudioWriteNR42(audio, 0);
396 GBAudioWriteNR43(audio, 0);
397 GBAudioWriteNR44(audio, 0);
398 GBAudioWriteNR50(audio, 0);
399 GBAudioWriteNR51(audio, 0);
400 if (audio->p) {
401 audio->p->memory.io[REG_NR10] = 0;
402 audio->p->memory.io[REG_NR11] = 0;
403 audio->p->memory.io[REG_NR12] = 0;
404 audio->p->memory.io[REG_NR13] = 0;
405 audio->p->memory.io[REG_NR14] = 0;
406 audio->p->memory.io[REG_NR21] = 0;
407 audio->p->memory.io[REG_NR22] = 0;
408 audio->p->memory.io[REG_NR23] = 0;
409 audio->p->memory.io[REG_NR24] = 0;
410 audio->p->memory.io[REG_NR30] = 0;
411 audio->p->memory.io[REG_NR31] = 0;
412 audio->p->memory.io[REG_NR32] = 0;
413 audio->p->memory.io[REG_NR33] = 0;
414 audio->p->memory.io[REG_NR34] = 0;
415 audio->p->memory.io[REG_NR42] = 0;
416 audio->p->memory.io[REG_NR43] = 0;
417 audio->p->memory.io[REG_NR44] = 0;
418 audio->p->memory.io[REG_NR50] = 0;
419 audio->p->memory.io[REG_NR51] = 0;
420 }
421 *audio->nr52 &= ~0x000F;
422 } else if (!wasEnable) {
423 audio->frame = 7;
424 }
425}
426
427int32_t GBAudioProcessEvents(struct GBAudio* audio, int32_t cycles) {
428 if (audio->nextEvent == INT_MAX) {
429 return INT_MAX;
430 }
431 audio->nextEvent -= cycles;
432 audio->eventDiff += cycles;
433 while (audio->nextEvent <= 0) {
434 audio->nextEvent = INT_MAX;
435 if (audio->enable) {
436 audio->nextFrame -= audio->eventDiff;
437 int frame = -1;
438 if (audio->nextFrame <= 0) {
439 frame = (audio->frame + 1) & 7;
440 audio->frame = frame;
441 audio->nextFrame += FRAME_CYCLES;
442 if (audio->nextFrame < audio->nextEvent) {
443 audio->nextEvent = audio->nextFrame;
444 }
445 }
446
447 if (audio->playingCh1) {
448 audio->nextCh1 -= audio->eventDiff;
449 if (!audio->ch1.envelope.dead && frame == 7) {
450 --audio->ch1.envelope.nextStep;
451 if (audio->ch1.envelope.nextStep == 0) {
452 int8_t sample = audio->ch1.control.hi * 0x10 - 0x8;
453 _updateEnvelope(&audio->ch1.envelope);
454 audio->ch1.sample = sample * audio->ch1.envelope.currentVolume;
455 }
456 }
457
458 if (audio->ch1.sweepEnable && (frame & 3) == 2) {
459 --audio->ch1.sweepStep;
460 if (audio->ch1.sweepStep == 0) {
461 audio->playingCh1 = _updateSweep(&audio->ch1, false);
462 }
463 }
464
465 if (audio->ch1.envelope.dead != 2) {
466 if (audio->nextCh1 <= 0) {
467 audio->nextCh1 += _updateChannel1(&audio->ch1);
468 }
469 if (audio->nextCh1 < audio->nextEvent) {
470 audio->nextEvent = audio->nextCh1;
471 }
472 }
473 }
474
475 if (audio->ch1.control.length && audio->ch1.control.stop && !(frame & 1)) {
476 --audio->ch1.control.length;
477 if (audio->ch1.control.length == 0) {
478 audio->playingCh1 = 0;
479 }
480 }
481
482 if (audio->playingCh2) {
483 audio->nextCh2 -= audio->eventDiff;
484 if (!audio->ch2.envelope.dead && frame == 7) {
485 --audio->ch2.envelope.nextStep;
486 if (audio->ch2.envelope.nextStep == 0) {
487 int8_t sample = audio->ch2.control.hi * 0x10 - 0x8;
488 _updateEnvelope(&audio->ch2.envelope);
489 audio->ch2.sample = sample * audio->ch2.envelope.currentVolume;
490 }
491 }
492
493 if (audio->ch2.envelope.dead != 2) {
494 if (audio->nextCh2 <= 0) {
495 audio->nextCh2 += _updateChannel2(&audio->ch2);
496 }
497 if (audio->nextCh2 < audio->nextEvent) {
498 audio->nextEvent = audio->nextCh2;
499 }
500 }
501 }
502
503 if (audio->ch2.control.length && audio->ch2.control.stop && !(frame & 1)) {
504 --audio->ch2.control.length;
505 if (audio->ch2.control.length == 0) {
506 audio->playingCh2 = 0;
507 }
508 }
509
510 if (audio->playingCh3) {
511 audio->nextCh3 -= audio->eventDiff;
512 audio->fadeCh3 -= audio->eventDiff;
513 if (audio->fadeCh3 <= 0) {
514 audio->ch3.readable = false;
515 audio->fadeCh3 = INT_MAX;
516 }
517 if (audio->nextCh3 <= 0) {
518 audio->fadeCh3 = audio->nextCh3 + 2;
519 audio->nextCh3 += _updateChannel3(&audio->ch3, audio->style);
520 audio->ch3.readable = true;
521 }
522 if (audio->fadeCh3 < audio->nextEvent) {
523 audio->nextEvent = audio->fadeCh3;
524 }
525 if (audio->nextCh3 < audio->nextEvent) {
526 audio->nextEvent = audio->nextCh3;
527 }
528 }
529
530 if (audio->ch3.length && audio->ch3.stop && !(frame & 1)) {
531 --audio->ch3.length;
532 if (audio->ch3.length == 0) {
533 audio->playingCh3 = 0;
534 }
535 }
536
537 if (audio->playingCh4) {
538 audio->nextCh4 -= audio->eventDiff;
539 if (!audio->ch4.envelope.dead && frame == 7) {
540 --audio->ch4.envelope.nextStep;
541 if (audio->ch4.envelope.nextStep == 0) {
542 int8_t sample = (audio->ch4.sample >> 31) * 0x8;
543 _updateEnvelope(&audio->ch4.envelope);
544 audio->ch4.sample = sample * audio->ch4.envelope.currentVolume;
545 }
546 }
547
548 if (audio->ch4.envelope.dead != 2) {
549 if (audio->nextCh4 <= 0) {
550 int32_t timing = _updateChannel4(&audio->ch4);
551 if (audio->nextCh4 < -timing) {
552 int32_t bound = timing * 16;
553 // Perform negative modulo to cap to 16 iterations
554 audio->nextCh4 = bound - (audio->nextCh4 - 1) % bound - 1;
555 }
556 audio->nextCh4 += timing;
557 }
558 if (audio->nextCh4 < audio->nextEvent) {
559 audio->nextEvent = audio->nextCh4;
560 }
561 }
562 }
563
564 if (audio->ch4.length && audio->ch4.stop && !(frame & 1)) {
565 --audio->ch4.length;
566 if (audio->ch4.length == 0) {
567 audio->playingCh4 = 0;
568 }
569 }
570 }
571
572 *audio->nr52 &= ~0x000F;
573 *audio->nr52 |= audio->playingCh1;
574 *audio->nr52 |= audio->playingCh2 << 1;
575 *audio->nr52 |= audio->playingCh3 << 2;
576 *audio->nr52 |= audio->playingCh4 << 3;
577
578 if (audio->p) {
579 audio->nextSample -= audio->eventDiff;
580 if (audio->nextSample <= 0) {
581 _sample(audio, audio->sampleInterval);
582 audio->nextSample += audio->sampleInterval;
583 }
584
585 if (audio->nextSample < audio->nextEvent) {
586 audio->nextEvent = audio->nextSample;
587 }
588 }
589 audio->eventDiff = 0;
590 }
591 return audio->nextEvent;
592}
593
594void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right) {
595 int sampleLeft = 0;
596 int sampleRight = 0;
597
598 if (audio->playingCh1 && !audio->forceDisableCh[0]) {
599 if (audio->ch1Left) {
600 sampleLeft += audio->ch1.sample;
601 }
602
603 if (audio->ch1Right) {
604 sampleRight += audio->ch1.sample;
605 }
606 }
607
608 if (audio->playingCh2 && !audio->forceDisableCh[1]) {
609 if (audio->ch2Left) {
610 sampleLeft += audio->ch2.sample;
611 }
612
613 if (audio->ch2Right) {
614 sampleRight += audio->ch2.sample;
615 }
616 }
617
618 if (audio->playingCh3 && !audio->forceDisableCh[2]) {
619 if (audio->ch3Left) {
620 sampleLeft += audio->ch3.sample;
621 }
622
623 if (audio->ch3Right) {
624 sampleRight += audio->ch3.sample;
625 }
626 }
627
628 if (audio->playingCh4 && !audio->forceDisableCh[3]) {
629 if (audio->ch4Left) {
630 sampleLeft += audio->ch4.sample;
631 }
632
633 if (audio->ch4Right) {
634 sampleRight += audio->ch4.sample;
635 }
636 }
637
638 *left = sampleLeft * (1 + audio->volumeLeft);
639 *right = sampleRight * (1 + audio->volumeRight);
640}
641
642void _sample(struct GBAudio* audio, int32_t cycles) {
643 int16_t sampleLeft = 0;
644 int16_t sampleRight = 0;
645 GBAudioSamplePSG(audio, &sampleLeft, &sampleRight);
646 sampleLeft = (sampleLeft * audio->masterVolume) >> 6;
647 sampleRight = (sampleRight * audio->masterVolume) >> 6;
648
649 mCoreSyncLockAudio(audio->p->sync);
650 unsigned produced;
651 if ((size_t) blip_samples_avail(audio->left) < audio->samples) {
652 blip_add_delta(audio->left, audio->clock, sampleLeft - audio->lastLeft);
653 blip_add_delta(audio->right, audio->clock, sampleRight - audio->lastRight);
654 audio->lastLeft = sampleLeft;
655 audio->lastRight = sampleRight;
656 audio->clock += cycles;
657 if (audio->clock >= CLOCKS_PER_BLIP_FRAME) {
658 blip_end_frame(audio->left, audio->clock);
659 blip_end_frame(audio->right, audio->clock);
660 audio->clock -= CLOCKS_PER_BLIP_FRAME;
661 }
662 }
663 produced = blip_samples_avail(audio->left);
664 bool wait = produced >= audio->samples;
665 mCoreSyncProduceAudio(audio->p->sync, wait);
666 // TODO: Put AVStream back
667}
668
669void _writeDuty(struct GBAudioEnvelope* envelope, uint8_t value) {
670 envelope->length = GBAudioRegisterDutyGetLength(value);
671 envelope->duty = GBAudioRegisterDutyGetDuty(value);
672}
673
674bool _writeSweep(struct GBAudioEnvelope* envelope, uint8_t value) {
675 envelope->stepTime = GBAudioRegisterSweepGetStepTime(value);
676 envelope->direction = GBAudioRegisterSweepGetDirection(value);
677 envelope->initialVolume = GBAudioRegisterSweepGetInitialVolume(value);
678 if (envelope->stepTime == 0) {
679 envelope->dead = envelope->currentVolume ? 1 : 2;
680 } else if (!envelope->direction && !envelope->currentVolume) {
681 envelope->dead = 2;
682 } else if (envelope->direction && envelope->currentVolume == 0xF) {
683 envelope->dead = 1;
684 } else {
685 envelope->dead = 0;
686 }
687 envelope->nextStep = envelope->stepTime;
688 return envelope->initialVolume || envelope->direction;
689}
690
691static int32_t _updateSquareChannel(struct GBAudioSquareControl* control, int duty) {
692 control->hi = !control->hi;
693 int period = 4 * (2048 - control->frequency);
694 switch (duty) {
695 case 0:
696 return control->hi ? period : period * 7;
697 case 1:
698 return control->hi ? period * 2 : period * 6;
699 case 2:
700 return period * 4;
701 case 3:
702 return control->hi ? period * 6 : period * 2;
703 default:
704 // This should never be hit
705 return period * 4;
706 }
707}
708
709static void _updateEnvelope(struct GBAudioEnvelope* envelope) {
710 if (envelope->direction) {
711 ++envelope->currentVolume;
712 } else {
713 --envelope->currentVolume;
714 }
715 if (envelope->currentVolume >= 15) {
716 envelope->currentVolume = 15;
717 envelope->dead = 1;
718 } else if (envelope->currentVolume <= 0) {
719 envelope->currentVolume = 0;
720 envelope->dead = 2;
721 } else {
722 envelope->nextStep = envelope->stepTime;
723 }
724}
725
726static bool _updateSweep(struct GBAudioChannel1* ch, bool initial) {
727 if (initial || ch->time != 8) {
728 int frequency = ch->control.frequency;
729 if (ch->direction) {
730 frequency -= frequency >> ch->shift;
731 if (!initial && frequency >= 0) {
732 ch->control.frequency = frequency;
733 ch->realFrequency = frequency;
734 }
735 } else {
736 frequency += frequency >> ch->shift;
737 if (frequency < 2048) {
738 if (!initial && ch->shift) {
739 ch->control.frequency = frequency;
740 if (!_updateSweep(ch, true)) {
741 return false;
742 }
743 ch->realFrequency = frequency;
744 }
745 } else {
746 return false;
747 }
748 }
749 ch->sweepOccurred = true;
750 }
751 ch->sweepStep = ch->time;
752 return true;
753}
754
755static int32_t _updateChannel1(struct GBAudioChannel1* ch) {
756 int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
757 ch->sample = ch->control.hi * 0x10 - 0x8;
758 ch->sample *= ch->envelope.currentVolume;
759 return timing;
760}
761
762static int32_t _updateChannel2(struct GBAudioChannel2* ch) {
763 int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
764 ch->sample = ch->control.hi * 0x10 - 0x8;
765 ch->sample *= ch->envelope.currentVolume;
766 return timing;
767}
768
769static int32_t _updateChannel3(struct GBAudioChannel3* ch, enum GBAudioStyle style) {
770 int i;
771 int volume;
772 switch (ch->volume) {
773 case 0:
774 volume = 0;
775 break;
776 case 1:
777 volume = 4;
778 break;
779 case 2:
780 volume = 2;
781 break;
782 case 3:
783 volume = 1;
784 break;
785 default:
786 volume = 3;
787 break;
788 }
789 switch (style) {
790 int start;
791 int end;
792 case GB_AUDIO_DMG:
793 default:
794 ++ch->window;
795 ch->window &= 0x1F;
796 ch->sample = ch->wavedata8[ch->window >> 1];
797 if (ch->window & 1) {
798 ch->sample &= 0xF;
799 } else {
800 ch->sample >>= 4;
801 }
802 break;
803 case GB_AUDIO_GBA:
804 if (ch->size) {
805 start = 7;
806 end = 0;
807 } else if (ch->bank) {
808 start = 7;
809 end = 4;
810 } else {
811 start = 3;
812 end = 0;
813 }
814 uint32_t bitsCarry = ch->wavedata32[end] & 0x000000F0;
815 uint32_t bits;
816 for (i = start; i >= end; --i) {
817 bits = ch->wavedata32[i] & 0x000000F0;
818 ch->wavedata32[i] = ((ch->wavedata32[i] & 0x0F0F0F0F) << 4) | ((ch->wavedata32[i] & 0xF0F0F000) >> 12);
819 ch->wavedata32[i] |= bitsCarry << 20;
820 bitsCarry = bits;
821 }
822 ch->sample = bitsCarry >> 4;
823 break;
824 }
825 ch->sample -= 8;
826 ch->sample *= volume * 4;
827 return 2 * (2048 - ch->rate);
828}
829
830static int32_t _updateChannel4(struct GBAudioChannel4* ch) {
831 int lsb = ch->lfsr & 1;
832 ch->sample = lsb * 0x10 - 0x8;
833 ch->sample *= ch->envelope.currentVolume;
834 ch->lfsr >>= 1;
835 ch->lfsr ^= (lsb * 0x60) << (ch->power ? 0 : 8);
836 int timing = ch->ratio ? 2 * ch->ratio : 1;
837 timing <<= ch->frequency;
838 timing *= 8;
839 return timing;
840}