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/interface.h"
9#include "core/sync.h"
10#include "gb/gb.h"
11#include "gb/io.h"
12
13#define FRAME_CYCLES (DMG_LR35902_FREQUENCY >> 9)
14
15const uint32_t DMG_LR35902_FREQUENCY = 0x400000;
16static const int CLOCKS_PER_BLIP_FRAME = 0x1000;
17static const unsigned BLIP_BUFFER_SIZE = 0x4000;
18const int GB_AUDIO_VOLUME_MAX = 0x100;
19
20static void _writeDuty(struct GBAudioEnvelope* envelope, uint8_t value);
21static bool _writeSweep(struct GBAudioEnvelope* envelope, uint8_t value);
22static int32_t _updateSquareChannel(struct GBAudioSquareControl* envelope, int duty);
23static void _updateEnvelope(struct GBAudioEnvelope* envelope);
24static bool _updateSweep(struct GBAudioChannel1* ch, bool initial);
25static int32_t _updateChannel1(struct GBAudioChannel1* ch);
26static int32_t _updateChannel2(struct GBAudioChannel2* ch);
27static int32_t _updateChannel3(struct GBAudioChannel3* ch, enum GBAudioStyle style);
28static int32_t _updateChannel4(struct GBAudioChannel4* ch);
29static void _sample(struct GBAudio* audio, int32_t cycles);
30static void _scheduleEvent(struct GBAudio* audio);
31
32void GBAudioInit(struct GBAudio* audio, size_t samples, uint8_t* nr52, enum GBAudioStyle style) {
33 audio->samples = samples;
34 audio->left = blip_new(BLIP_BUFFER_SIZE);
35 audio->right = blip_new(BLIP_BUFFER_SIZE);
36 audio->clockRate = DMG_LR35902_FREQUENCY;
37 // Guess too large; we hang producing extra samples if we guess too low
38 blip_set_rates(audio->left, DMG_LR35902_FREQUENCY, 96000);
39 blip_set_rates(audio->right, DMG_LR35902_FREQUENCY, 96000);
40 audio->forceDisableCh[0] = false;
41 audio->forceDisableCh[1] = false;
42 audio->forceDisableCh[2] = false;
43 audio->forceDisableCh[3] = false;
44 audio->masterVolume = GB_AUDIO_VOLUME_MAX;
45 audio->nr52 = nr52;
46 audio->style = style;
47}
48
49void GBAudioDeinit(struct GBAudio* audio) {
50 blip_delete(audio->left);
51 blip_delete(audio->right);
52}
53
54void GBAudioReset(struct GBAudio* audio) {
55 audio->nextEvent = 0;
56 audio->nextCh1 = 0;
57 audio->nextCh2 = 0;
58 audio->nextCh3 = 0;
59 audio->fadeCh3 = 0;
60 audio->nextCh4 = 0;
61 audio->ch1 = (struct GBAudioChannel1) { .envelope = { .dead = 2 } };
62 audio->ch2 = (struct GBAudioChannel2) { .envelope = { .dead = 2 } };
63 audio->ch3 = (struct GBAudioChannel3) { .bank = 0 };
64 audio->ch4 = (struct GBAudioChannel4) { .envelope = { .dead = 2 } };
65 audio->eventDiff = 0;
66 audio->nextFrame = 0;
67 audio->frame = 0;
68 audio->nextSample = 0;
69 audio->sampleInterval = 128;
70 audio->lastLeft = 0;
71 audio->lastRight = 0;
72 audio->clock = 0;
73 audio->volumeRight = 0;
74 audio->volumeLeft = 0;
75 audio->ch1Right = false;
76 audio->ch2Right = false;
77 audio->ch3Right = false;
78 audio->ch4Right = false;
79 audio->ch1Left = false;
80 audio->ch2Left = false;
81 audio->ch3Left = false;
82 audio->ch4Left = false;
83 audio->playingCh1 = false;
84 audio->playingCh2 = false;
85 audio->playingCh3 = false;
86 audio->playingCh4 = false;
87}
88
89void GBAudioResizeBuffer(struct GBAudio* audio, size_t samples) {
90 mCoreSyncLockAudio(audio->p->sync);
91 audio->samples = samples;
92 blip_clear(audio->left);
93 blip_clear(audio->right);
94 audio->clock = 0;
95 mCoreSyncConsumeAudio(audio->p->sync);
96}
97
98void GBAudioWriteNR10(struct GBAudio* audio, uint8_t value) {
99 audio->ch1.shift = GBAudioRegisterSquareSweepGetShift(value);
100 bool oldDirection = audio->ch1.direction;
101 audio->ch1.direction = GBAudioRegisterSquareSweepGetDirection(value);
102 if (audio->ch1.sweepOccurred && oldDirection && !audio->ch1.direction) {
103 audio->playingCh1 = false;
104 *audio->nr52 &= ~0x0001;
105 }
106 audio->ch1.sweepOccurred = false;
107 audio->ch1.time = GBAudioRegisterSquareSweepGetTime(value);
108 if (!audio->ch1.time) {
109 audio->ch1.time = 8;
110 }
111}
112
113void GBAudioWriteNR11(struct GBAudio* audio, uint8_t value) {
114 _writeDuty(&audio->ch1.envelope, value);
115 audio->ch1.control.length = 64 - audio->ch1.envelope.length;
116}
117
118void GBAudioWriteNR12(struct GBAudio* audio, uint8_t value) {
119 if (!_writeSweep(&audio->ch1.envelope, value)) {
120 audio->playingCh1 = false;
121 *audio->nr52 &= ~0x0001;
122 }
123}
124
125void GBAudioWriteNR13(struct GBAudio* audio, uint8_t value) {
126 audio->ch1.control.frequency &= 0x700;
127 audio->ch1.control.frequency |= GBAudioRegisterControlGetFrequency(value);
128}
129
130void GBAudioWriteNR14(struct GBAudio* audio, uint8_t value) {
131 audio->ch1.control.frequency &= 0xFF;
132 audio->ch1.control.frequency |= GBAudioRegisterControlGetFrequency(value << 8);
133 bool wasStop = audio->ch1.control.stop;
134 audio->ch1.control.stop = GBAudioRegisterControlGetStop(value << 8);
135 if (!wasStop && audio->ch1.control.stop && audio->ch1.control.length && !(audio->frame & 1)) {
136 --audio->ch1.control.length;
137 if (audio->ch1.control.length == 0) {
138 audio->playingCh1 = false;
139 }
140 }
141 if (GBAudioRegisterControlIsRestart(value << 8)) {
142 if (audio->nextEvent == INT_MAX) {
143 audio->eventDiff = 0;
144 }
145 if (!audio->playingCh1) {
146 audio->nextCh1 = audio->eventDiff;
147 }
148 audio->playingCh1 = audio->ch1.envelope.initialVolume || audio->ch1.envelope.direction;
149 audio->ch1.envelope.currentVolume = audio->ch1.envelope.initialVolume;
150 if (audio->ch1.envelope.currentVolume > 0) {
151 audio->ch1.envelope.dead = audio->ch1.envelope.stepTime ? 0 : 1;
152 }
153 audio->ch1.realFrequency = audio->ch1.control.frequency;
154 audio->ch1.sweepStep = audio->ch1.time;
155 audio->ch1.sweepEnable = (audio->ch1.sweepStep != 8) || audio->ch1.shift;
156 audio->ch1.sweepOccurred = false;
157 if (audio->playingCh1 && audio->ch1.shift) {
158 audio->playingCh1 = _updateSweep(&audio->ch1, true);
159 }
160 if (!audio->ch1.control.length) {
161 audio->ch1.control.length = 64;
162 if (audio->ch1.control.stop && !(audio->frame & 1)) {
163 --audio->ch1.control.length;
164 }
165 }
166 _scheduleEvent(audio);
167 }
168 *audio->nr52 &= ~0x0001;
169 *audio->nr52 |= audio->playingCh1;
170}
171
172void GBAudioWriteNR21(struct GBAudio* audio, uint8_t value) {
173 _writeDuty(&audio->ch2.envelope, value);
174 audio->ch2.control.length = 64 - audio->ch2.envelope.length;
175}
176
177void GBAudioWriteNR22(struct GBAudio* audio, uint8_t value) {
178 if (!_writeSweep(&audio->ch2.envelope, value)) {
179 audio->playingCh2 = false;
180 *audio->nr52 &= ~0x0002;
181 }
182}
183
184void GBAudioWriteNR23(struct GBAudio* audio, uint8_t value) {
185 audio->ch2.control.frequency &= 0x700;
186 audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value);
187}
188
189void GBAudioWriteNR24(struct GBAudio* audio, uint8_t value) {
190 audio->ch2.control.frequency &= 0xFF;
191 audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value << 8);
192 bool wasStop = audio->ch2.control.stop;
193 audio->ch2.control.stop = GBAudioRegisterControlGetStop(value << 8);
194 if (!wasStop && audio->ch2.control.stop && audio->ch2.control.length && !(audio->frame & 1)) {
195 --audio->ch2.control.length;
196 if (audio->ch2.control.length == 0) {
197 audio->playingCh2 = false;
198 }
199 }
200 if (GBAudioRegisterControlIsRestart(value << 8)) {
201 audio->playingCh2 = audio->ch2.envelope.initialVolume || audio->ch2.envelope.direction;
202 audio->ch2.envelope.currentVolume = audio->ch2.envelope.initialVolume;
203 if (audio->ch2.envelope.currentVolume > 0) {
204 audio->ch2.envelope.dead = audio->ch2.envelope.stepTime ? 0 : 1;
205 }
206 if (audio->nextEvent == INT_MAX) {
207 audio->eventDiff = 0;
208 }
209 if (!audio->playingCh2) {
210 audio->nextCh2 = audio->eventDiff;
211 }
212 if (!audio->ch2.control.length) {
213 audio->ch2.control.length = 64;
214 if (audio->ch2.control.stop && !(audio->frame & 1)) {
215 --audio->ch2.control.length;
216 }
217 }
218 _scheduleEvent(audio);
219 }
220 *audio->nr52 &= ~0x0002;
221 *audio->nr52 |= audio->playingCh2 << 1;
222}
223
224void GBAudioWriteNR30(struct GBAudio* audio, uint8_t value) {
225 audio->ch3.enable = GBAudioRegisterBankGetEnable(value);
226 if (!audio->ch3.enable) {
227 audio->playingCh3 = false;
228 *audio->nr52 &= ~0x0004;
229 }
230}
231
232void GBAudioWriteNR31(struct GBAudio* audio, uint8_t value) {
233 audio->ch3.length = 256 - value;
234}
235
236void GBAudioWriteNR32(struct GBAudio* audio, uint8_t value) {
237 audio->ch3.volume = GBAudioRegisterBankVolumeGetVolumeGB(value);
238}
239
240void GBAudioWriteNR33(struct GBAudio* audio, uint8_t value) {
241 audio->ch3.rate &= 0x700;
242 audio->ch3.rate |= GBAudioRegisterControlGetRate(value);
243}
244
245void GBAudioWriteNR34(struct GBAudio* audio, uint8_t value) {
246 audio->ch3.rate &= 0xFF;
247 audio->ch3.rate |= GBAudioRegisterControlGetRate(value << 8);
248 bool wasStop = audio->ch3.stop;
249 audio->ch3.stop = GBAudioRegisterControlGetStop(value << 8);
250 if (!wasStop && audio->ch3.stop && audio->ch3.length && !(audio->frame & 1)) {
251 --audio->ch3.length;
252 if (audio->ch3.length == 0) {
253 audio->playingCh3 = false;
254 }
255 }
256 bool wasEnable = audio->playingCh3;
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->style == GB_AUDIO_DMG && wasEnable && audio->playingCh3 && audio->ch3.readable) {
267 if (audio->ch3.window < 8) {
268 audio->ch3.wavedata8[0] = audio->ch3.wavedata8[audio->ch3.window >> 1];
269 } else {
270 audio->ch3.wavedata8[0] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3)];
271 audio->ch3.wavedata8[1] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 1];
272 audio->ch3.wavedata8[2] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 2];
273 audio->ch3.wavedata8[3] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 3];
274 }
275 }
276 audio->ch3.window = 0;
277 }
278 if (audio->playingCh3) {
279 if (audio->nextEvent == INT_MAX) {
280 audio->eventDiff = 0;
281 }
282 audio->ch3.readable = audio->style != GB_AUDIO_DMG;
283 _scheduleEvent(audio);
284 // TODO: Where does this cycle delay come from?
285 audio->nextCh3 = audio->eventDiff + audio->nextEvent + 4 + 2 * (2048 - audio->ch3.rate);
286 }
287 *audio->nr52 &= ~0x0004;
288 *audio->nr52 |= audio->playingCh3 << 2;
289}
290
291void GBAudioWriteNR41(struct GBAudio* audio, uint8_t value) {
292 _writeDuty(&audio->ch4.envelope, value);
293 audio->ch4.length = 64 - audio->ch4.envelope.length;
294}
295
296void GBAudioWriteNR42(struct GBAudio* audio, uint8_t value) {
297 if (!_writeSweep(&audio->ch4.envelope, value)) {
298 audio->playingCh4 = false;
299 *audio->nr52 &= ~0x0008;
300 }
301}
302
303void GBAudioWriteNR43(struct GBAudio* audio, uint8_t value) {
304 audio->ch4.ratio = GBAudioRegisterNoiseFeedbackGetRatio(value);
305 audio->ch4.frequency = GBAudioRegisterNoiseFeedbackGetFrequency(value);
306 audio->ch4.power = GBAudioRegisterNoiseFeedbackGetPower(value);
307}
308
309void GBAudioWriteNR44(struct GBAudio* audio, uint8_t value) {
310 bool wasStop = audio->ch4.stop;
311 audio->ch4.stop = GBAudioRegisterNoiseControlGetStop(value);
312 if (!wasStop && audio->ch4.stop && audio->ch4.length && !(audio->frame & 1)) {
313 --audio->ch4.length;
314 if (audio->ch4.length == 0) {
315 audio->playingCh4 = false;
316 }
317 }
318 if (GBAudioRegisterNoiseControlIsRestart(value)) {
319 audio->playingCh4 = audio->ch4.envelope.initialVolume || audio->ch4.envelope.direction;
320 audio->ch4.envelope.currentVolume = audio->ch4.envelope.initialVolume;
321 if (audio->ch4.envelope.currentVolume > 0) {
322 audio->ch4.envelope.dead = audio->ch4.envelope.stepTime ? 0 : 1;
323 }
324 if (audio->ch4.power) {
325 audio->ch4.lfsr = 0x40;
326 } else {
327 audio->ch4.lfsr = 0x4000;
328 }
329 if (audio->nextEvent == INT_MAX) {
330 audio->eventDiff = 0;
331 }
332 if (!audio->playingCh4) {
333 audio->nextCh4 = audio->eventDiff;
334 }
335 if (!audio->ch4.length) {
336 audio->ch4.length = 64;
337 if (audio->ch4.stop && !(audio->frame & 1)) {
338 --audio->ch4.length;
339 }
340 }
341 _scheduleEvent(audio);
342 }
343 *audio->nr52 &= ~0x0008;
344 *audio->nr52 |= audio->playingCh4 << 3;
345}
346
347void GBAudioWriteNR50(struct GBAudio* audio, uint8_t value) {
348 audio->volumeRight = GBRegisterNR50GetVolumeRight(value);
349 audio->volumeLeft = GBRegisterNR50GetVolumeLeft(value);
350}
351
352void GBAudioWriteNR51(struct GBAudio* audio, uint8_t value) {
353 audio->ch1Right = GBRegisterNR51GetCh1Right(value);
354 audio->ch2Right = GBRegisterNR51GetCh2Right(value);
355 audio->ch3Right = GBRegisterNR51GetCh3Right(value);
356 audio->ch4Right = GBRegisterNR51GetCh4Right(value);
357 audio->ch1Left = GBRegisterNR51GetCh1Left(value);
358 audio->ch2Left = GBRegisterNR51GetCh2Left(value);
359 audio->ch3Left = GBRegisterNR51GetCh3Left(value);
360 audio->ch4Left = GBRegisterNR51GetCh4Left(value);
361}
362
363void GBAudioWriteNR52(struct GBAudio* audio, uint8_t value) {
364 bool wasEnable = audio->enable;
365 audio->enable = GBAudioEnableGetEnable(value);
366 if (!audio->enable) {
367 audio->playingCh1 = 0;
368 audio->playingCh2 = 0;
369 audio->playingCh3 = 0;
370 audio->playingCh4 = 0;
371 GBAudioWriteNR10(audio, 0);
372 GBAudioWriteNR12(audio, 0);
373 GBAudioWriteNR13(audio, 0);
374 GBAudioWriteNR14(audio, 0);
375 GBAudioWriteNR22(audio, 0);
376 GBAudioWriteNR23(audio, 0);
377 GBAudioWriteNR24(audio, 0);
378 GBAudioWriteNR30(audio, 0);
379 GBAudioWriteNR32(audio, 0);
380 GBAudioWriteNR33(audio, 0);
381 GBAudioWriteNR34(audio, 0);
382 GBAudioWriteNR42(audio, 0);
383 GBAudioWriteNR43(audio, 0);
384 GBAudioWriteNR44(audio, 0);
385 GBAudioWriteNR50(audio, 0);
386 GBAudioWriteNR51(audio, 0);
387 if (audio->style != GB_AUDIO_DMG) {
388 GBAudioWriteNR11(audio, 0);
389 GBAudioWriteNR21(audio, 0);
390 GBAudioWriteNR31(audio, 0);
391 GBAudioWriteNR41(audio, 0);
392 }
393
394 if (audio->p) {
395 audio->p->memory.io[REG_NR10] = 0;
396 audio->p->memory.io[REG_NR11] = 0;
397 audio->p->memory.io[REG_NR12] = 0;
398 audio->p->memory.io[REG_NR13] = 0;
399 audio->p->memory.io[REG_NR14] = 0;
400 audio->p->memory.io[REG_NR21] = 0;
401 audio->p->memory.io[REG_NR22] = 0;
402 audio->p->memory.io[REG_NR23] = 0;
403 audio->p->memory.io[REG_NR24] = 0;
404 audio->p->memory.io[REG_NR30] = 0;
405 audio->p->memory.io[REG_NR31] = 0;
406 audio->p->memory.io[REG_NR32] = 0;
407 audio->p->memory.io[REG_NR33] = 0;
408 audio->p->memory.io[REG_NR34] = 0;
409 audio->p->memory.io[REG_NR42] = 0;
410 audio->p->memory.io[REG_NR43] = 0;
411 audio->p->memory.io[REG_NR44] = 0;
412 audio->p->memory.io[REG_NR50] = 0;
413 audio->p->memory.io[REG_NR51] = 0;
414 if (audio->style != GB_AUDIO_DMG) {
415 audio->p->memory.io[REG_NR11] = 0;
416 audio->p->memory.io[REG_NR21] = 0;
417 audio->p->memory.io[REG_NR31] = 0;
418 audio->p->memory.io[REG_NR41] = 0;
419 }
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 if (audio->style == GB_AUDIO_DMG) {
519 audio->fadeCh3 = audio->nextCh3 + 2;
520 }
521 audio->nextCh3 += _updateChannel3(&audio->ch3, audio->style);
522 audio->ch3.readable = true;
523 }
524 if (audio->fadeCh3 < audio->nextEvent) {
525 audio->nextEvent = audio->fadeCh3;
526 }
527 if (audio->nextCh3 < audio->nextEvent) {
528 audio->nextEvent = audio->nextCh3;
529 }
530 }
531
532 if (audio->ch3.length && audio->ch3.stop && !(frame & 1)) {
533 --audio->ch3.length;
534 if (audio->ch3.length == 0) {
535 audio->playingCh3 = 0;
536 }
537 }
538
539 if (audio->playingCh4) {
540 audio->nextCh4 -= audio->eventDiff;
541 if (!audio->ch4.envelope.dead && frame == 7) {
542 --audio->ch4.envelope.nextStep;
543 if (audio->ch4.envelope.nextStep == 0) {
544 int8_t sample = (audio->ch4.sample >> 31) * 0x8;
545 _updateEnvelope(&audio->ch4.envelope);
546 audio->ch4.sample = sample * audio->ch4.envelope.currentVolume;
547 }
548 }
549
550 if (audio->ch4.envelope.dead != 2) {
551 if (audio->nextCh4 <= 0) {
552 int32_t timing = _updateChannel4(&audio->ch4);
553 if (audio->nextCh4 < -timing) {
554 int32_t bound = timing * 16;
555 // Perform negative modulo to cap to 16 iterations
556 audio->nextCh4 = bound - (audio->nextCh4 - 1) % bound - 1;
557 }
558 audio->nextCh4 += timing;
559 }
560 if (audio->nextCh4 < audio->nextEvent) {
561 audio->nextEvent = audio->nextCh4;
562 }
563 }
564 }
565
566 if (audio->ch4.length && audio->ch4.stop && !(frame & 1)) {
567 --audio->ch4.length;
568 if (audio->ch4.length == 0) {
569 audio->playingCh4 = 0;
570 }
571 }
572 }
573
574 *audio->nr52 &= ~0x000F;
575 *audio->nr52 |= audio->playingCh1;
576 *audio->nr52 |= audio->playingCh2 << 1;
577 *audio->nr52 |= audio->playingCh3 << 2;
578 *audio->nr52 |= audio->playingCh4 << 3;
579
580 if (audio->p) {
581 audio->nextSample -= audio->eventDiff;
582 if (audio->nextSample <= 0) {
583 _sample(audio, audio->sampleInterval);
584 audio->nextSample += audio->sampleInterval;
585 }
586
587 if (audio->nextSample < audio->nextEvent) {
588 audio->nextEvent = audio->nextSample;
589 }
590 }
591 audio->eventDiff = 0;
592 }
593 return audio->nextEvent;
594}
595
596void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right) {
597 int sampleLeft = 0;
598 int sampleRight = 0;
599
600 if (audio->playingCh1 && !audio->forceDisableCh[0]) {
601 if (audio->ch1Left) {
602 sampleLeft += audio->ch1.sample;
603 }
604
605 if (audio->ch1Right) {
606 sampleRight += audio->ch1.sample;
607 }
608 }
609
610 if (audio->playingCh2 && !audio->forceDisableCh[1]) {
611 if (audio->ch2Left) {
612 sampleLeft += audio->ch2.sample;
613 }
614
615 if (audio->ch2Right) {
616 sampleRight += audio->ch2.sample;
617 }
618 }
619
620 if (audio->playingCh3 && !audio->forceDisableCh[2]) {
621 if (audio->ch3Left) {
622 sampleLeft += audio->ch3.sample;
623 }
624
625 if (audio->ch3Right) {
626 sampleRight += audio->ch3.sample;
627 }
628 }
629
630 if (audio->playingCh4 && !audio->forceDisableCh[3]) {
631 if (audio->ch4Left) {
632 sampleLeft += audio->ch4.sample;
633 }
634
635 if (audio->ch4Right) {
636 sampleRight += audio->ch4.sample;
637 }
638 }
639
640 *left = sampleLeft * (1 + audio->volumeLeft);
641 *right = sampleRight * (1 + audio->volumeRight);
642}
643
644void _sample(struct GBAudio* audio, int32_t cycles) {
645 int16_t sampleLeft = 0;
646 int16_t sampleRight = 0;
647 GBAudioSamplePSG(audio, &sampleLeft, &sampleRight);
648 sampleLeft = (sampleLeft * audio->masterVolume) >> 6;
649 sampleRight = (sampleRight * audio->masterVolume) >> 6;
650
651 mCoreSyncLockAudio(audio->p->sync);
652 unsigned produced;
653 if ((size_t) blip_samples_avail(audio->left) < audio->samples) {
654 blip_add_delta(audio->left, audio->clock, sampleLeft - audio->lastLeft);
655 blip_add_delta(audio->right, audio->clock, sampleRight - audio->lastRight);
656 audio->lastLeft = sampleLeft;
657 audio->lastRight = sampleRight;
658 audio->clock += cycles;
659 if (audio->clock >= CLOCKS_PER_BLIP_FRAME) {
660 blip_end_frame(audio->left, audio->clock);
661 blip_end_frame(audio->right, audio->clock);
662 audio->clock -= CLOCKS_PER_BLIP_FRAME;
663 }
664 }
665 produced = blip_samples_avail(audio->left);
666 if (audio->p->stream && audio->p->stream->postAudioFrame) {
667 audio->p->stream->postAudioFrame(audio->p->stream, sampleLeft, sampleRight);
668 }
669 bool wait = produced >= audio->samples;
670 mCoreSyncProduceAudio(audio->p->sync, wait);
671
672 if (wait && audio->p->stream && audio->p->stream->postAudioBuffer) {
673 audio->p->stream->postAudioBuffer(audio->p->stream, audio->left, audio->right);
674 }
675}
676
677void _writeDuty(struct GBAudioEnvelope* envelope, uint8_t value) {
678 envelope->length = GBAudioRegisterDutyGetLength(value);
679 envelope->duty = GBAudioRegisterDutyGetDuty(value);
680}
681
682bool _writeSweep(struct GBAudioEnvelope* envelope, uint8_t value) {
683 envelope->stepTime = GBAudioRegisterSweepGetStepTime(value);
684 envelope->direction = GBAudioRegisterSweepGetDirection(value);
685 envelope->initialVolume = GBAudioRegisterSweepGetInitialVolume(value);
686 if (envelope->stepTime == 0) {
687 envelope->dead = envelope->currentVolume ? 1 : 2;
688 } else if (!envelope->direction && !envelope->currentVolume) {
689 envelope->dead = 2;
690 } else if (envelope->direction && envelope->currentVolume == 0xF) {
691 envelope->dead = 1;
692 } else {
693 envelope->dead = 0;
694 }
695 envelope->nextStep = envelope->stepTime;
696 return envelope->initialVolume || envelope->direction;
697}
698
699static int32_t _updateSquareChannel(struct GBAudioSquareControl* control, int duty) {
700 control->hi = !control->hi;
701 int period = 4 * (2048 - control->frequency);
702 switch (duty) {
703 case 0:
704 return control->hi ? period : period * 7;
705 case 1:
706 return control->hi ? period * 2 : period * 6;
707 case 2:
708 return period * 4;
709 case 3:
710 return control->hi ? period * 6 : period * 2;
711 default:
712 // This should never be hit
713 return period * 4;
714 }
715}
716
717static void _updateEnvelope(struct GBAudioEnvelope* envelope) {
718 if (envelope->direction) {
719 ++envelope->currentVolume;
720 } else {
721 --envelope->currentVolume;
722 }
723 if (envelope->currentVolume >= 15) {
724 envelope->currentVolume = 15;
725 envelope->dead = 1;
726 } else if (envelope->currentVolume <= 0) {
727 envelope->currentVolume = 0;
728 envelope->dead = 2;
729 } else {
730 envelope->nextStep = envelope->stepTime;
731 }
732}
733
734static bool _updateSweep(struct GBAudioChannel1* ch, bool initial) {
735 if (initial || ch->time != 8) {
736 int frequency = ch->realFrequency;
737 if (ch->direction) {
738 frequency -= frequency >> ch->shift;
739 if (!initial && frequency >= 0) {
740 ch->control.frequency = frequency;
741 ch->realFrequency = frequency;
742 }
743 } else {
744 frequency += frequency >> ch->shift;
745 if (frequency < 2048) {
746 if (!initial && ch->shift) {
747 ch->control.frequency = frequency;
748 ch->realFrequency = frequency;
749 if (!_updateSweep(ch, true)) {
750 return false;
751 }
752 }
753 } else {
754 return false;
755 }
756 }
757 ch->sweepOccurred = true;
758 }
759 ch->sweepStep = ch->time;
760 return true;
761}
762
763static int32_t _updateChannel1(struct GBAudioChannel1* ch) {
764 int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
765 ch->sample = ch->control.hi * 0x10 - 0x8;
766 ch->sample *= ch->envelope.currentVolume;
767 return timing;
768}
769
770static int32_t _updateChannel2(struct GBAudioChannel2* ch) {
771 int timing = _updateSquareChannel(&ch->control, ch->envelope.duty);
772 ch->sample = ch->control.hi * 0x10 - 0x8;
773 ch->sample *= ch->envelope.currentVolume;
774 return timing;
775}
776
777static int32_t _updateChannel3(struct GBAudioChannel3* ch, enum GBAudioStyle style) {
778 int i;
779 int volume;
780 switch (ch->volume) {
781 case 0:
782 volume = 0;
783 break;
784 case 1:
785 volume = 4;
786 break;
787 case 2:
788 volume = 2;
789 break;
790 case 3:
791 volume = 1;
792 break;
793 default:
794 volume = 3;
795 break;
796 }
797 switch (style) {
798 int start;
799 int end;
800 case GB_AUDIO_DMG:
801 default:
802 ++ch->window;
803 ch->window &= 0x1F;
804 ch->sample = ch->wavedata8[ch->window >> 1];
805 if (!(ch->window & 1)) {
806 ch->sample >>= 4;
807 }
808 ch->sample &= 0xF;
809 break;
810 case GB_AUDIO_GBA:
811 if (ch->size) {
812 start = 7;
813 end = 0;
814 } else if (ch->bank) {
815 start = 7;
816 end = 4;
817 } else {
818 start = 3;
819 end = 0;
820 }
821 uint32_t bitsCarry = ch->wavedata32[end] & 0x000000F0;
822 uint32_t bits;
823 for (i = start; i >= end; --i) {
824 bits = ch->wavedata32[i] & 0x000000F0;
825 ch->wavedata32[i] = ((ch->wavedata32[i] & 0x0F0F0F0F) << 4) | ((ch->wavedata32[i] & 0xF0F0F000) >> 12);
826 ch->wavedata32[i] |= bitsCarry << 20;
827 bitsCarry = bits;
828 }
829 ch->sample = bitsCarry >> 4;
830 break;
831 }
832 ch->sample -= 8;
833 ch->sample *= volume * 4;
834 return 2 * (2048 - ch->rate);
835}
836
837static int32_t _updateChannel4(struct GBAudioChannel4* ch) {
838 int lsb = ch->lfsr & 1;
839 ch->sample = lsb * 0x10 - 0x8;
840 ch->sample *= ch->envelope.currentVolume;
841 ch->lfsr >>= 1;
842 ch->lfsr ^= (lsb * 0x60) << (ch->power ? 0 : 8);
843 int timing = ch->ratio ? 2 * ch->ratio : 1;
844 timing <<= ch->frequency;
845 timing *= 8;
846 return timing;
847}
848
849void _scheduleEvent(struct GBAudio* audio) {
850 // TODO: Don't need p
851 if (audio->p) {
852 audio->nextEvent = audio->p->cpu->cycles >> audio->p->doubleSpeed;
853 audio->p->cpu->nextEvent = audio->nextEvent;
854 } else {
855 audio->nextEvent = 0;
856 }
857}