all repos — mgba @ 327c3e78c6f3b4efb60a79c77e36c376754d2085

mGBA Game Boy Advance Emulator

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/serialize.h"
 12#include "gb/io.h"
 13
 14#ifdef _3DS
 15#define blip_add_delta blip_add_delta_fast
 16#endif
 17
 18#define FRAME_CYCLES (DMG_LR35902_FREQUENCY >> 9)
 19
 20const uint32_t DMG_LR35902_FREQUENCY = 0x400000;
 21static const int CLOCKS_PER_BLIP_FRAME = 0x1000;
 22static const unsigned BLIP_BUFFER_SIZE = 0x4000;
 23const int GB_AUDIO_VOLUME_MAX = 0x100;
 24
 25static bool _writeSweep(struct GBAudioSweep* sweep, uint8_t value);
 26static void _writeDuty(struct GBAudioEnvelope* envelope, uint8_t value);
 27static bool _writeEnvelope(struct GBAudioEnvelope* envelope, uint8_t value);
 28
 29static void _resetSweep(struct GBAudioSweep* sweep);
 30static bool _resetEnvelope(struct GBAudioEnvelope* sweep);
 31
 32static void _updateEnvelope(struct GBAudioEnvelope* envelope);
 33static void _updateEnvelopeDead(struct GBAudioEnvelope* envelope);
 34static bool _updateSweep(struct GBAudioSquareChannel* sweep, bool initial);
 35
 36static void _updateSquareSample(struct GBAudioSquareChannel* ch);
 37static int32_t _updateSquareChannel(struct GBAudioSquareChannel* ch);
 38
 39static void _updateFrame(struct mTiming* timing, void* user, uint32_t cyclesLate);
 40static void _updateChannel1(struct mTiming* timing, void* user, uint32_t cyclesLate);
 41static void _updateChannel2(struct mTiming* timing, void* user, uint32_t cyclesLate);
 42static void _updateChannel3(struct mTiming* timing, void* user, uint32_t cyclesLate);
 43static void _fadeChannel3(struct mTiming* timing, void* user, uint32_t cyclesLate);
 44static void _updateChannel4(struct mTiming* timing, void* user, uint32_t cyclesLate);
 45static void _sample(struct mTiming* timing, void* user, uint32_t cyclesLate);
 46
 47void GBAudioInit(struct GBAudio* audio, size_t samples, uint8_t* nr52, enum GBAudioStyle style) {
 48	audio->samples = samples;
 49	audio->left = blip_new(BLIP_BUFFER_SIZE);
 50	audio->right = blip_new(BLIP_BUFFER_SIZE);
 51	audio->clockRate = DMG_LR35902_FREQUENCY;
 52	// Guess too large; we hang producing extra samples if we guess too low
 53	blip_set_rates(audio->left, DMG_LR35902_FREQUENCY, 96000);
 54	blip_set_rates(audio->right, DMG_LR35902_FREQUENCY, 96000);
 55	audio->forceDisableCh[0] = false;
 56	audio->forceDisableCh[1] = false;
 57	audio->forceDisableCh[2] = false;
 58	audio->forceDisableCh[3] = false;
 59	audio->masterVolume = GB_AUDIO_VOLUME_MAX;
 60	audio->nr52 = nr52;
 61	audio->style = style;
 62	if (style == GB_AUDIO_GBA) {
 63		audio->timingFactor = 4;
 64	} else {
 65		audio->timingFactor = 1;
 66	}
 67
 68	audio->frameEvent.context = audio;
 69	audio->frameEvent.name = "GB Audio Frame Sequencer";
 70	audio->frameEvent.callback = _updateFrame;
 71	audio->ch1Event.context = audio;
 72	audio->ch1Event.name = "GB Audio Channel 1";
 73	audio->ch1Event.callback = _updateChannel1;
 74	audio->ch2Event.context = audio;
 75	audio->ch2Event.name = "GB Audio Channel 2";
 76	audio->ch2Event.callback = _updateChannel2;
 77	audio->ch3Event.context = audio;
 78	audio->ch3Event.name = "GB Audio Channel 3";
 79	audio->ch3Event.callback = _updateChannel3;
 80	audio->ch3Fade.context = audio;
 81	audio->ch3Fade.name = "GB Audio Channel 3 Memory";
 82	audio->ch3Fade.callback = _fadeChannel3;
 83	audio->ch4Event.context = audio;
 84	audio->ch4Event.name = "GB Audio Channel 4";
 85	audio->ch4Event.callback = _updateChannel4;
 86	audio->sampleEvent.context = audio;
 87	audio->sampleEvent.name = "GB Audio Sample";
 88	audio->sampleEvent.callback = _sample;
 89}
 90
 91void GBAudioDeinit(struct GBAudio* audio) {
 92	blip_delete(audio->left);
 93	blip_delete(audio->right);
 94}
 95
 96void GBAudioReset(struct GBAudio* audio) {
 97	mTimingDeschedule(audio->timing, &audio->frameEvent);
 98	mTimingDeschedule(audio->timing, &audio->ch1Event);
 99	mTimingDeschedule(audio->timing, &audio->ch2Event);
100	mTimingDeschedule(audio->timing, &audio->ch3Event);
101	mTimingDeschedule(audio->timing, &audio->ch3Fade);
102	mTimingDeschedule(audio->timing, &audio->ch4Event);
103	mTimingDeschedule(audio->timing, &audio->sampleEvent);
104	mTimingSchedule(audio->timing, &audio->frameEvent, 0);
105	if (audio->style != GB_AUDIO_GBA) {
106		mTimingSchedule(audio->timing, &audio->sampleEvent, 0);
107	}
108	audio->ch1 = (struct GBAudioSquareChannel) { .envelope = { .dead = 2 } };
109	audio->ch2 = (struct GBAudioSquareChannel) { .envelope = { .dead = 2 } };
110	audio->ch3 = (struct GBAudioWaveChannel) { .bank = 0 };
111	// TODO: DMG randomness
112	audio->ch3.wavedata8[0] = 0x00;
113	audio->ch3.wavedata8[1] = 0xFF;
114	audio->ch3.wavedata8[2] = 0x00;
115	audio->ch3.wavedata8[3] = 0xFF;
116	audio->ch3.wavedata8[4] = 0x00;
117	audio->ch3.wavedata8[5] = 0xFF;
118	audio->ch3.wavedata8[6] = 0x00;
119	audio->ch3.wavedata8[7] = 0xFF;
120	audio->ch3.wavedata8[8] = 0x00;
121	audio->ch3.wavedata8[9] = 0xFF;
122	audio->ch3.wavedata8[10] = 0x00;
123	audio->ch3.wavedata8[11] = 0xFF;
124	audio->ch3.wavedata8[12] = 0x00;
125	audio->ch3.wavedata8[13] = 0xFF;
126	audio->ch3.wavedata8[14] = 0x00;
127	audio->ch3.wavedata8[15] = 0xFF;
128	audio->ch4 = (struct GBAudioNoiseChannel) { .envelope = { .dead = 2 } };
129	audio->frame = 0;
130	audio->sampleInterval = 128;
131	audio->lastLeft = 0;
132	audio->lastRight = 0;
133	audio->clock = 0;
134	audio->volumeRight = 0;
135	audio->volumeLeft = 0;
136	audio->ch1Right = false;
137	audio->ch2Right = false;
138	audio->ch3Right = false;
139	audio->ch4Right = false;
140	audio->ch1Left = false;
141	audio->ch2Left = false;
142	audio->ch3Left = false;
143	audio->ch4Left = false;
144	audio->playingCh1 = false;
145	audio->playingCh2 = false;
146	audio->playingCh3 = false;
147	audio->playingCh4 = false;
148}
149
150void GBAudioResizeBuffer(struct GBAudio* audio, size_t samples) {
151	mCoreSyncLockAudio(audio->p->sync);
152	audio->samples = samples;
153	blip_clear(audio->left);
154	blip_clear(audio->right);
155	audio->clock = 0;
156	mCoreSyncConsumeAudio(audio->p->sync);
157}
158
159void GBAudioWriteNR10(struct GBAudio* audio, uint8_t value) {
160	if (!_writeSweep(&audio->ch1.sweep, value)) {
161		mTimingDeschedule(audio->timing, &audio->ch1Event);
162		audio->playingCh1 = false;
163		*audio->nr52 &= ~0x0001;
164	}
165}
166
167void GBAudioWriteNR11(struct GBAudio* audio, uint8_t value) {
168	_writeDuty(&audio->ch1.envelope, value);
169	audio->ch1.control.length = 64 - audio->ch1.envelope.length;
170}
171
172void GBAudioWriteNR12(struct GBAudio* audio, uint8_t value) {
173	if (!_writeEnvelope(&audio->ch1.envelope, value)) {
174		mTimingDeschedule(audio->timing, &audio->ch1Event);
175		audio->playingCh1 = false;
176		*audio->nr52 &= ~0x0001;
177	}
178}
179
180void GBAudioWriteNR13(struct GBAudio* audio, uint8_t value) {
181	audio->ch1.control.frequency &= 0x700;
182	audio->ch1.control.frequency |= GBAudioRegisterControlGetFrequency(value);
183}
184
185void GBAudioWriteNR14(struct GBAudio* audio, uint8_t value) {
186	audio->ch1.control.frequency &= 0xFF;
187	audio->ch1.control.frequency |= GBAudioRegisterControlGetFrequency(value << 8);
188	bool wasStop = audio->ch1.control.stop;
189	audio->ch1.control.stop = GBAudioRegisterControlGetStop(value << 8);
190	if (!wasStop && audio->ch1.control.stop && audio->ch1.control.length && !(audio->frame & 1)) {
191		--audio->ch1.control.length;
192		if (audio->ch1.control.length == 0) {
193			mTimingDeschedule(audio->timing, &audio->ch1Event);
194			audio->playingCh1 = false;
195		}
196	}
197	if (GBAudioRegisterControlIsRestart(value << 8)) {
198		audio->playingCh1 = _resetEnvelope(&audio->ch1.envelope);
199
200		if (audio->playingCh1) {
201			audio->ch1.control.hi = 0;
202			_updateSquareSample(&audio->ch1);
203		}
204
205		audio->ch1.sweep.realFrequency = audio->ch1.control.frequency;
206		_resetSweep(&audio->ch1.sweep);
207		if (audio->playingCh1 && audio->ch1.sweep.shift) {
208			audio->playingCh1 = _updateSweep(&audio->ch1, true);
209		}
210		if (!audio->ch1.control.length) {
211			audio->ch1.control.length = 64;
212			if (audio->ch1.control.stop && !(audio->frame & 1)) {
213				--audio->ch1.control.length;
214			}
215		}
216		mTimingDeschedule(audio->timing, &audio->ch1Event);
217		if (audio->playingCh1 && audio->ch1.envelope.dead != 2) {
218			mTimingSchedule(audio->timing, &audio->ch1Event, 0);
219		}
220	}
221	*audio->nr52 &= ~0x0001;
222	*audio->nr52 |= audio->playingCh1;
223}
224
225void GBAudioWriteNR21(struct GBAudio* audio, uint8_t value) {
226	_writeDuty(&audio->ch2.envelope, value);
227	audio->ch2.control.length = 64 - audio->ch2.envelope.length;
228}
229
230void GBAudioWriteNR22(struct GBAudio* audio, uint8_t value) {
231	if (!_writeEnvelope(&audio->ch2.envelope, value)) {
232		mTimingDeschedule(audio->timing, &audio->ch2Event);
233		audio->playingCh2 = false;
234		*audio->nr52 &= ~0x0002;
235	}
236}
237
238void GBAudioWriteNR23(struct GBAudio* audio, uint8_t value) {
239	audio->ch2.control.frequency &= 0x700;
240	audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value);
241}
242
243void GBAudioWriteNR24(struct GBAudio* audio, uint8_t value) {
244	audio->ch2.control.frequency &= 0xFF;
245	audio->ch2.control.frequency |= GBAudioRegisterControlGetFrequency(value << 8);
246	bool wasStop = audio->ch2.control.stop;
247	audio->ch2.control.stop = GBAudioRegisterControlGetStop(value << 8);
248	if (!wasStop && audio->ch2.control.stop && audio->ch2.control.length && !(audio->frame & 1)) {
249		--audio->ch2.control.length;
250		if (audio->ch2.control.length == 0) {
251			mTimingDeschedule(audio->timing, &audio->ch2Event);
252			audio->playingCh2 = false;
253		}
254	}
255	if (GBAudioRegisterControlIsRestart(value << 8)) {
256		audio->playingCh2 = _resetEnvelope(&audio->ch2.envelope);
257
258		if (audio->playingCh2) {
259			audio->ch2.control.hi = 0;
260			_updateSquareSample(&audio->ch2);
261		}
262
263		if (!audio->ch2.control.length) {
264			audio->ch2.control.length = 64;
265			if (audio->ch2.control.stop && !(audio->frame & 1)) {
266				--audio->ch2.control.length;
267			}
268		}
269		mTimingDeschedule(audio->timing, &audio->ch2Event);
270		if (audio->playingCh2 && audio->ch2.envelope.dead != 2) {
271			mTimingSchedule(audio->timing, &audio->ch2Event, 0);
272		}
273	}
274	*audio->nr52 &= ~0x0002;
275	*audio->nr52 |= audio->playingCh2 << 1;
276}
277
278void GBAudioWriteNR30(struct GBAudio* audio, uint8_t value) {
279	audio->ch3.enable = GBAudioRegisterBankGetEnable(value);
280	if (!audio->ch3.enable) {
281		audio->playingCh3 = false;
282		*audio->nr52 &= ~0x0004;
283	}
284}
285
286void GBAudioWriteNR31(struct GBAudio* audio, uint8_t value) {
287	audio->ch3.length = 256 - value;
288}
289
290void GBAudioWriteNR32(struct GBAudio* audio, uint8_t value) {
291	audio->ch3.volume = GBAudioRegisterBankVolumeGetVolumeGB(value);
292}
293
294void GBAudioWriteNR33(struct GBAudio* audio, uint8_t value) {
295	audio->ch3.rate &= 0x700;
296	audio->ch3.rate |= GBAudioRegisterControlGetRate(value);
297}
298
299void GBAudioWriteNR34(struct GBAudio* audio, uint8_t value) {
300	audio->ch3.rate &= 0xFF;
301	audio->ch3.rate |= GBAudioRegisterControlGetRate(value << 8);
302	bool wasStop = audio->ch3.stop;
303	audio->ch3.stop = GBAudioRegisterControlGetStop(value << 8);
304	if (!wasStop && audio->ch3.stop && audio->ch3.length && !(audio->frame & 1)) {
305		--audio->ch3.length;
306		if (audio->ch3.length == 0) {
307			audio->playingCh3 = false;
308		}
309	}
310	bool wasEnable = audio->playingCh3;
311	if (GBAudioRegisterControlIsRestart(value << 8)) {
312		audio->playingCh3 = audio->ch3.enable;
313		if (!audio->ch3.length) {
314			audio->ch3.length = 256;
315			if (audio->ch3.stop && !(audio->frame & 1)) {
316				--audio->ch3.length;
317			}
318		}
319
320		if (audio->style == GB_AUDIO_DMG && wasEnable && audio->playingCh3 && audio->ch3.readable) {
321			if (audio->ch3.window < 8) {
322				audio->ch3.wavedata8[0] = audio->ch3.wavedata8[audio->ch3.window >> 1];
323			} else {
324				audio->ch3.wavedata8[0] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3)];
325				audio->ch3.wavedata8[1] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 1];
326				audio->ch3.wavedata8[2] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 2];
327				audio->ch3.wavedata8[3] = audio->ch3.wavedata8[((audio->ch3.window >> 1) & ~3) + 3];
328			}
329		}
330		audio->ch3.window = 0;
331	}
332	mTimingDeschedule(audio->timing, &audio->ch3Event);
333	if (audio->playingCh3) {
334		audio->ch3.readable = audio->style != GB_AUDIO_DMG;
335		// TODO: Where does this cycle delay come from?
336		mTimingSchedule(audio->timing, &audio->ch3Event, audio->timingFactor * 4 + 2 * (2048 - audio->ch3.rate));
337	}
338	*audio->nr52 &= ~0x0004;
339	*audio->nr52 |= audio->playingCh3 << 2;
340}
341
342void GBAudioWriteNR41(struct GBAudio* audio, uint8_t value) {
343	_writeDuty(&audio->ch4.envelope, value);
344	audio->ch4.length = 64 - audio->ch4.envelope.length;
345}
346
347void GBAudioWriteNR42(struct GBAudio* audio, uint8_t value) {
348	if (!_writeEnvelope(&audio->ch4.envelope, value)) {
349		mTimingDeschedule(audio->timing, &audio->ch4Event);
350		audio->playingCh4 = false;
351		*audio->nr52 &= ~0x0008;
352	}
353}
354
355void GBAudioWriteNR43(struct GBAudio* audio, uint8_t value) {
356	audio->ch4.ratio = GBAudioRegisterNoiseFeedbackGetRatio(value);
357	audio->ch4.frequency = GBAudioRegisterNoiseFeedbackGetFrequency(value);
358	audio->ch4.power = GBAudioRegisterNoiseFeedbackGetPower(value);
359}
360
361void GBAudioWriteNR44(struct GBAudio* audio, uint8_t value) {
362	bool wasStop = audio->ch4.stop;
363	audio->ch4.stop = GBAudioRegisterNoiseControlGetStop(value);
364	if (!wasStop && audio->ch4.stop && audio->ch4.length && !(audio->frame & 1)) {
365		--audio->ch4.length;
366		if (audio->ch4.length == 0) {
367			mTimingDeschedule(audio->timing, &audio->ch4Event);
368			audio->playingCh4 = false;
369		}
370	}
371	if (GBAudioRegisterNoiseControlIsRestart(value)) {
372		audio->playingCh4 = _resetEnvelope(&audio->ch4.envelope);
373
374		if (audio->ch4.power) {
375			audio->ch4.lfsr = 0x40;
376		} else {
377			audio->ch4.lfsr = 0x4000;
378		}
379		if (!audio->ch4.length) {
380			audio->ch4.length = 64;
381			if (audio->ch4.stop && !(audio->frame & 1)) {
382				--audio->ch4.length;
383			}
384		}
385		mTimingDeschedule(audio->timing, &audio->ch4Event);
386		if (audio->playingCh4 && audio->ch4.envelope.dead != 2) {
387			mTimingSchedule(audio->timing, &audio->ch4Event, 0);
388		}
389	}
390	*audio->nr52 &= ~0x0008;
391	*audio->nr52 |= audio->playingCh4 << 3;
392}
393
394void GBAudioWriteNR50(struct GBAudio* audio, uint8_t value) {
395	audio->volumeRight = GBRegisterNR50GetVolumeRight(value);
396	audio->volumeLeft = GBRegisterNR50GetVolumeLeft(value);
397}
398
399void GBAudioWriteNR51(struct GBAudio* audio, uint8_t value) {
400	audio->ch1Right = GBRegisterNR51GetCh1Right(value);
401	audio->ch2Right = GBRegisterNR51GetCh2Right(value);
402	audio->ch3Right = GBRegisterNR51GetCh3Right(value);
403	audio->ch4Right = GBRegisterNR51GetCh4Right(value);
404	audio->ch1Left = GBRegisterNR51GetCh1Left(value);
405	audio->ch2Left = GBRegisterNR51GetCh2Left(value);
406	audio->ch3Left = GBRegisterNR51GetCh3Left(value);
407	audio->ch4Left = GBRegisterNR51GetCh4Left(value);
408}
409
410void GBAudioWriteNR52(struct GBAudio* audio, uint8_t value) {
411	bool wasEnable = audio->enable;
412	audio->enable = GBAudioEnableGetEnable(value);
413	if (!audio->enable) {
414		audio->playingCh1 = 0;
415		audio->playingCh2 = 0;
416		audio->playingCh3 = 0;
417		audio->playingCh4 = 0;
418		GBAudioWriteNR10(audio, 0);
419		GBAudioWriteNR12(audio, 0);
420		GBAudioWriteNR13(audio, 0);
421		GBAudioWriteNR14(audio, 0);
422		GBAudioWriteNR22(audio, 0);
423		GBAudioWriteNR23(audio, 0);
424		GBAudioWriteNR24(audio, 0);
425		GBAudioWriteNR30(audio, 0);
426		GBAudioWriteNR32(audio, 0);
427		GBAudioWriteNR33(audio, 0);
428		GBAudioWriteNR34(audio, 0);
429		GBAudioWriteNR42(audio, 0);
430		GBAudioWriteNR43(audio, 0);
431		GBAudioWriteNR44(audio, 0);
432		GBAudioWriteNR50(audio, 0);
433		GBAudioWriteNR51(audio, 0);
434		if (audio->style != GB_AUDIO_DMG) {
435			GBAudioWriteNR11(audio, 0);
436			GBAudioWriteNR21(audio, 0);
437			GBAudioWriteNR31(audio, 0);
438			GBAudioWriteNR41(audio, 0);
439		}
440
441		if (audio->p) {
442			audio->p->memory.io[REG_NR10] = 0;
443			audio->p->memory.io[REG_NR11] = 0;
444			audio->p->memory.io[REG_NR12] = 0;
445			audio->p->memory.io[REG_NR13] = 0;
446			audio->p->memory.io[REG_NR14] = 0;
447			audio->p->memory.io[REG_NR21] = 0;
448			audio->p->memory.io[REG_NR22] = 0;
449			audio->p->memory.io[REG_NR23] = 0;
450			audio->p->memory.io[REG_NR24] = 0;
451			audio->p->memory.io[REG_NR30] = 0;
452			audio->p->memory.io[REG_NR31] = 0;
453			audio->p->memory.io[REG_NR32] = 0;
454			audio->p->memory.io[REG_NR33] = 0;
455			audio->p->memory.io[REG_NR34] = 0;
456			audio->p->memory.io[REG_NR42] = 0;
457			audio->p->memory.io[REG_NR43] = 0;
458			audio->p->memory.io[REG_NR44] = 0;
459			audio->p->memory.io[REG_NR50] = 0;
460			audio->p->memory.io[REG_NR51] = 0;
461			if (audio->style != GB_AUDIO_DMG) {
462				audio->p->memory.io[REG_NR11] = 0;
463				audio->p->memory.io[REG_NR21] = 0;
464				audio->p->memory.io[REG_NR31] = 0;
465				audio->p->memory.io[REG_NR41] = 0;
466			}
467		}
468		*audio->nr52 &= ~0x000F;
469	} else if (!wasEnable) {
470		audio->frame = 7;
471	}
472}
473
474void _updateFrame(struct mTiming* timing, void* user, uint32_t cyclesLate) {
475	struct GBAudio* audio = user;
476
477	int frame = (audio->frame + 1) & 7;
478	audio->frame = frame;
479
480	switch (frame) {
481	case 2:
482	case 6:
483		if (audio->ch1.sweep.enable) {
484			--audio->ch1.sweep.step;
485			if (audio->ch1.sweep.step == 0) {
486				audio->playingCh1 = _updateSweep(&audio->ch1, false);
487				*audio->nr52 &= ~0x0001;
488				*audio->nr52 |= audio->playingCh1;
489			}
490		}
491		// Fall through
492	case 0:
493	case 4:
494		if (audio->ch1.control.length && audio->ch1.control.stop) {
495			--audio->ch1.control.length;
496			if (audio->ch1.control.length == 0) {
497				mTimingDeschedule(timing, &audio->ch1Event);
498				audio->playingCh1 = 0;
499				*audio->nr52 &= ~0x0001;
500			}
501		}
502
503		if (audio->ch2.control.length && audio->ch2.control.stop) {
504			--audio->ch2.control.length;
505			if (audio->ch2.control.length == 0) {
506				mTimingDeschedule(timing, &audio->ch2Event);
507				audio->playingCh2 = 0;
508				*audio->nr52 &= ~0x0002;
509			}
510		}
511
512		if (audio->ch3.length && audio->ch3.stop) {
513			--audio->ch3.length;
514			if (audio->ch3.length == 0) {
515				mTimingDeschedule(timing, &audio->ch3Event);
516				audio->playingCh3 = 0;
517				*audio->nr52 &= ~0x0004;
518			}
519		}
520
521		if (audio->ch4.length && audio->ch4.stop) {
522			--audio->ch4.length;
523			if (audio->ch4.length == 0) {
524				mTimingDeschedule(timing, &audio->ch4Event);
525				audio->playingCh4 = 0;
526				*audio->nr52 &= ~0x0008;
527			}
528		}
529		break;
530	case 7:
531		if (audio->playingCh1 && !audio->ch1.envelope.dead) {
532			--audio->ch1.envelope.nextStep;
533			if (audio->ch1.envelope.nextStep == 0) {
534				_updateEnvelope(&audio->ch1.envelope);
535				if (audio->ch1.envelope.dead == 2) {
536					mTimingDeschedule(timing, &audio->ch1Event);
537				}
538				_updateSquareSample(&audio->ch1);
539			}
540		}
541
542		if (audio->playingCh2 && !audio->ch2.envelope.dead) {
543			--audio->ch2.envelope.nextStep;
544			if (audio->ch2.envelope.nextStep == 0) {
545				_updateEnvelope(&audio->ch2.envelope);
546				if (audio->ch2.envelope.dead == 2) {
547					mTimingDeschedule(timing, &audio->ch2Event);
548				}
549				_updateSquareSample(&audio->ch1);
550			}
551		}
552
553		if (audio->playingCh4 && !audio->ch4.envelope.dead) {
554			--audio->ch4.envelope.nextStep;
555			if (audio->ch4.envelope.nextStep == 0) {
556				int8_t sample = (audio->ch4.sample >> 7) * 0x8;
557				_updateEnvelope(&audio->ch4.envelope);
558				if (audio->ch4.envelope.dead == 2) {
559					mTimingDeschedule(timing, &audio->ch4Event);
560				}
561				audio->ch4.sample = sample * audio->ch4.envelope.currentVolume;
562			}
563		}
564		break;
565	}
566
567	mTimingSchedule(timing, &audio->frameEvent, audio->timingFactor * FRAME_CYCLES - cyclesLate);
568}
569
570void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right) {
571	int sampleLeft = 0;
572	int sampleRight = 0;
573
574	if (audio->playingCh1 && !audio->forceDisableCh[0]) {
575		if (audio->ch1Left) {
576			sampleLeft += audio->ch1.sample;
577		}
578
579		if (audio->ch1Right) {
580			sampleRight += audio->ch1.sample;
581		}
582	}
583
584	if (audio->playingCh2 && !audio->forceDisableCh[1]) {
585		if (audio->ch2Left) {
586			sampleLeft += audio->ch2.sample;
587		}
588
589		if (audio->ch2Right) {
590			sampleRight += audio->ch2.sample;
591		}
592	}
593
594	if (audio->playingCh3 && !audio->forceDisableCh[2]) {
595		if (audio->ch3Left) {
596			sampleLeft += audio->ch3.sample;
597		}
598
599		if (audio->ch3Right) {
600			sampleRight += audio->ch3.sample;
601		}
602	}
603
604	if (audio->playingCh4 && !audio->forceDisableCh[3]) {
605		if (audio->ch4Left) {
606			sampleLeft += audio->ch4.sample;
607		}
608
609		if (audio->ch4Right) {
610			sampleRight += audio->ch4.sample;
611		}
612	}
613
614	*left = sampleLeft * (1 + audio->volumeLeft);
615	*right = sampleRight * (1 + audio->volumeRight);
616}
617
618static void _sample(struct mTiming* timing, void* user, uint32_t cyclesLate) {
619	struct GBAudio* audio = user;
620	int16_t sampleLeft = 0;
621	int16_t sampleRight = 0;
622	GBAudioSamplePSG(audio, &sampleLeft, &sampleRight);
623	sampleLeft = (sampleLeft * audio->masterVolume) >> 6;
624	sampleRight = (sampleRight * audio->masterVolume) >> 6;
625
626	mCoreSyncLockAudio(audio->p->sync);
627	unsigned produced;
628	if ((size_t) blip_samples_avail(audio->left) < audio->samples) {
629		blip_add_delta(audio->left, audio->clock, sampleLeft - audio->lastLeft);
630		blip_add_delta(audio->right, audio->clock, sampleRight - audio->lastRight);
631		audio->lastLeft = sampleLeft;
632		audio->lastRight = sampleRight;
633		audio->clock += audio->sampleInterval;
634		if (audio->clock >= CLOCKS_PER_BLIP_FRAME) {
635			blip_end_frame(audio->left, audio->clock);
636			blip_end_frame(audio->right, audio->clock);
637			audio->clock -= CLOCKS_PER_BLIP_FRAME;
638		}
639	}
640	produced = blip_samples_avail(audio->left);
641	if (audio->p->stream && audio->p->stream->postAudioFrame) {
642		audio->p->stream->postAudioFrame(audio->p->stream, sampleLeft, sampleRight);
643	}
644	bool wait = produced >= audio->samples;
645	mCoreSyncProduceAudio(audio->p->sync, wait);
646
647	if (wait && audio->p->stream && audio->p->stream->postAudioBuffer) {
648		audio->p->stream->postAudioBuffer(audio->p->stream, audio->left, audio->right);
649	}
650	mTimingSchedule(timing, &audio->sampleEvent, audio->sampleInterval * audio->timingFactor - cyclesLate);
651}
652
653bool _resetEnvelope(struct GBAudioEnvelope* envelope) {
654	envelope->currentVolume = envelope->initialVolume;
655	_updateEnvelopeDead(envelope);
656	if (!envelope->dead) {
657		envelope->nextStep = envelope->stepTime;
658	}
659	return envelope->initialVolume || envelope->direction;
660}
661
662void _resetSweep(struct GBAudioSweep* sweep) {
663	sweep->step = sweep->time;
664	sweep->enable = (sweep->step != 8) || sweep->shift;
665	sweep->occurred = false;
666}
667
668bool _writeSweep(struct GBAudioSweep* sweep, uint8_t value) {
669	sweep->shift = GBAudioRegisterSquareSweepGetShift(value);
670	bool oldDirection = sweep->direction;
671	sweep->direction = GBAudioRegisterSquareSweepGetDirection(value);
672	bool on = true;
673	if (sweep->occurred && oldDirection && !sweep->direction) {
674		on = false;
675	}
676	sweep->occurred = false;
677	sweep->time = GBAudioRegisterSquareSweepGetTime(value);
678	if (!sweep->time) {
679		sweep->time = 8;
680	}
681	return on;
682}
683
684void _writeDuty(struct GBAudioEnvelope* envelope, uint8_t value) {
685	envelope->length = GBAudioRegisterDutyGetLength(value);
686	envelope->duty = GBAudioRegisterDutyGetDuty(value);
687}
688
689bool _writeEnvelope(struct GBAudioEnvelope* envelope, uint8_t value) {
690	envelope->stepTime = GBAudioRegisterSweepGetStepTime(value);
691	envelope->direction = GBAudioRegisterSweepGetDirection(value);
692	envelope->initialVolume = GBAudioRegisterSweepGetInitialVolume(value);
693	_updateEnvelopeDead(envelope);
694	envelope->nextStep = envelope->stepTime;
695	return (envelope->initialVolume || envelope->direction) && envelope->dead != 2;
696}
697
698static void _updateSquareSample(struct GBAudioSquareChannel* ch) {
699	ch->sample = (ch->control.hi * ch->envelope.currentVolume - 8) * 0x10;
700}
701
702static int32_t _updateSquareChannel(struct GBAudioSquareChannel* ch) {
703	ch->control.hi = !ch->control.hi;
704	_updateSquareSample(ch);
705	int period = 4 * (2048 - ch->control.frequency);
706	switch (ch->envelope.duty) {
707	case 0:
708		return ch->control.hi ? period : period * 7;
709	case 1:
710		return ch->control.hi ? period * 2 : period * 6;
711	case 2:
712		return period * 4;
713	case 3:
714		return ch->control.hi ? period * 6 : period * 2;
715	default:
716		// This should never be hit
717		return period * 4;
718	}
719}
720
721static void _updateEnvelope(struct GBAudioEnvelope* envelope) {
722	if (envelope->direction) {
723		++envelope->currentVolume;
724	} else {
725		--envelope->currentVolume;
726	}
727	if (envelope->currentVolume >= 15) {
728		envelope->currentVolume = 15;
729		envelope->dead = 1;
730	} else if (envelope->currentVolume <= 0) {
731		envelope->currentVolume = 0;
732		envelope->dead = 2;
733	} else {
734		envelope->nextStep = envelope->stepTime;
735	}
736}
737
738static void _updateEnvelopeDead(struct GBAudioEnvelope* envelope) {
739	if (!envelope->stepTime) {
740		envelope->dead = envelope->currentVolume ? 1 : 2;
741	} else if (!envelope->direction && !envelope->currentVolume) {
742		envelope->dead = 2;
743	} else if (envelope->direction && envelope->currentVolume == 0xF) {
744		envelope->dead = 1;
745	} else {
746		envelope->dead = 0;
747	}
748}
749
750static bool _updateSweep(struct GBAudioSquareChannel* ch, bool initial) {
751	if (initial || ch->sweep.time != 8) {
752		int frequency = ch->sweep.realFrequency;
753		if (ch->sweep.direction) {
754			frequency -= frequency >> ch->sweep.shift;
755			if (!initial && frequency >= 0) {
756				ch->control.frequency = frequency;
757				ch->sweep.realFrequency = frequency;
758			}
759		} else {
760			frequency += frequency >> ch->sweep.shift;
761			if (frequency < 2048) {
762				if (!initial && ch->sweep.shift) {
763					ch->control.frequency = frequency;
764					ch->sweep.realFrequency = frequency;
765					if (!_updateSweep(ch, true)) {
766						return false;
767					}
768				}
769			} else {
770				return false;
771			}
772		}
773		ch->sweep.occurred = true;
774	}
775	ch->sweep.step = ch->sweep.time;
776	return true;
777}
778
779static void _updateChannel1(struct mTiming* timing, void* user, uint32_t cyclesLate) {
780	struct GBAudio* audio = user;
781	struct GBAudioSquareChannel* ch = &audio->ch1;
782	int cycles = _updateSquareChannel(ch);
783	mTimingSchedule(timing, &audio->ch1Event, audio->timingFactor * cycles - cyclesLate);
784}
785
786static void _updateChannel2(struct mTiming* timing, void* user, uint32_t cyclesLate) {
787	struct GBAudio* audio = user;
788	struct GBAudioSquareChannel* ch = &audio->ch2;
789	int cycles = _updateSquareChannel(ch);
790	mTimingSchedule(timing, &audio->ch2Event, audio->timingFactor * cycles - cyclesLate);
791}
792
793static void _updateChannel3(struct mTiming* timing, void* user, uint32_t cyclesLate) {
794	struct GBAudio* audio = user;
795	struct GBAudioWaveChannel* ch = &audio->ch3;
796	int i;
797	int volume;
798	switch (ch->volume) {
799	case 0:
800		volume = 0;
801		break;
802	case 1:
803		volume = 4;
804		break;
805	case 2:
806		volume = 2;
807		break;
808	case 3:
809		volume = 1;
810		break;
811	default:
812		volume = 3;
813		break;
814	}
815	int start;
816	int end;
817	switch (audio->style) {
818	case GB_AUDIO_DMG:
819	default:
820		++ch->window;
821		ch->window &= 0x1F;
822		ch->sample = ch->wavedata8[ch->window >> 1];
823		if (!(ch->window & 1)) {
824			ch->sample >>= 4;
825		}
826		ch->sample &= 0xF;
827		break;
828	case GB_AUDIO_GBA:
829		if (ch->size) {
830			start = 7;
831			end = 0;
832		} else if (ch->bank) {
833			start = 7;
834			end = 4;
835		} else {
836			start = 3;
837			end = 0;
838		}
839		uint32_t bitsCarry = ch->wavedata32[end] & 0x000000F0;
840		uint32_t bits;
841		for (i = start; i >= end; --i) {
842			bits = ch->wavedata32[i] & 0x000000F0;
843			ch->wavedata32[i] = ((ch->wavedata32[i] & 0x0F0F0F0F) << 4) | ((ch->wavedata32[i] & 0xF0F0F000) >> 12);
844			ch->wavedata32[i] |= bitsCarry << 20;
845			bitsCarry = bits;
846		}
847		ch->sample = bitsCarry >> 4;
848		break;
849	}
850	ch->sample -= 8;
851	ch->sample *= volume * 4;
852	audio->ch3.readable = true;
853	if (audio->style == GB_AUDIO_DMG) {
854		mTimingSchedule(timing, &audio->ch3Fade, 2 - cyclesLate);
855	}
856	int cycles = 2 * (2048 - ch->rate);
857	mTimingSchedule(timing, &audio->ch3Event, audio->timingFactor * cycles - cyclesLate);
858}
859static void _fadeChannel3(struct mTiming* timing, void* user, uint32_t cyclesLate) {
860	UNUSED(timing);
861	UNUSED(cyclesLate);
862	struct GBAudio* audio = user;
863	audio->ch3.readable = false;
864}
865
866static void _updateChannel4(struct mTiming* timing, void* user, uint32_t cyclesLate) {
867	struct GBAudio* audio = user;
868	struct GBAudioNoiseChannel* ch = &audio->ch4;
869	int lsb = ch->lfsr & 1;
870	ch->sample = lsb * 0x10 - 0x8;
871	ch->sample *= ch->envelope.currentVolume;
872	ch->lfsr >>= 1;
873	ch->lfsr ^= (lsb * 0x60) << (ch->power ? 0 : 8);
874	int cycles = ch->ratio ? 2 * ch->ratio : 1;
875	cycles <<= ch->frequency;
876	cycles *= 8;
877	mTimingSchedule(timing, &audio->ch4Event, audio->timingFactor * cycles - cyclesLate);
878}
879
880void GBAudioPSGSerialize(const struct GBAudio* audio, struct GBSerializedPSGState* state, uint32_t* flagsOut) {
881	uint32_t flags = 0;
882	uint32_t ch1Flags = 0;
883	uint32_t ch2Flags = 0;
884	uint32_t ch4Flags = 0;
885
886	flags = GBSerializedAudioFlagsSetFrame(flags, audio->frame);
887
888	flags = GBSerializedAudioFlagsSetCh1Volume(flags, audio->ch1.envelope.currentVolume);
889	flags = GBSerializedAudioFlagsSetCh1Dead(flags, audio->ch1.envelope.dead);
890	flags = GBSerializedAudioFlagsSetCh1Hi(flags, audio->ch1.control.hi);
891	flags = GBSerializedAudioFlagsSetCh1SweepEnabled(flags, audio->ch1.sweep.enable);
892	flags = GBSerializedAudioFlagsSetCh1SweepOccurred(flags, audio->ch1.sweep.occurred);
893	ch1Flags = GBSerializedAudioEnvelopeSetLength(ch1Flags, audio->ch1.control.length);
894	ch1Flags = GBSerializedAudioEnvelopeSetNextStep(ch1Flags, audio->ch1.envelope.nextStep);
895	ch1Flags = GBSerializedAudioEnvelopeSetFrequency(ch1Flags, audio->ch1.sweep.realFrequency);
896	STORE_32LE(ch1Flags, 0, &state->ch1.envelope);
897
898	flags = GBSerializedAudioFlagsSetCh2Volume(flags, audio->ch2.envelope.currentVolume);
899	flags = GBSerializedAudioFlagsSetCh2Dead(flags, audio->ch2.envelope.dead);
900	flags = GBSerializedAudioFlagsSetCh2Hi(flags, audio->ch2.control.hi);
901	ch2Flags = GBSerializedAudioEnvelopeSetLength(ch2Flags, audio->ch2.control.length);
902	ch2Flags = GBSerializedAudioEnvelopeSetNextStep(ch2Flags, audio->ch2.envelope.nextStep);
903	STORE_32LE(ch2Flags, 0, &state->ch2.envelope);
904
905	memcpy(state->ch3.wavebanks, audio->ch3.wavedata32, sizeof(state->ch3.wavebanks));
906	STORE_16LE(audio->ch3.length, 0, &state->ch3.length);
907
908	flags = GBSerializedAudioFlagsSetCh4Volume(flags, audio->ch4.envelope.currentVolume);
909	flags = GBSerializedAudioFlagsSetCh4Dead(flags, audio->ch4.envelope.dead);
910	STORE_32LE(audio->ch4.lfsr, 0, &state->ch4.lfsr);
911	ch4Flags = GBSerializedAudioEnvelopeSetLength(ch4Flags, audio->ch4.length);
912	ch4Flags = GBSerializedAudioEnvelopeSetNextStep(ch4Flags, audio->ch4.envelope.nextStep);
913	STORE_32LE(ch4Flags, 0, &state->ch4.envelope);
914
915	STORE_32LE(flags, 0, flagsOut);
916}
917
918void GBAudioPSGDeserialize(struct GBAudio* audio, const struct GBSerializedPSGState* state, const uint32_t* flagsIn) {
919	uint32_t flags;
920	uint32_t ch1Flags = 0;
921	uint32_t ch2Flags = 0;
922	uint32_t ch4Flags = 0;
923
924	audio->playingCh1 = !!(*audio->nr52 & 0x0001);
925	audio->playingCh2 = !!(*audio->nr52 & 0x0002);
926	audio->playingCh3 = !!(*audio->nr52 & 0x0004);
927	audio->playingCh4 = !!(*audio->nr52 & 0x0008);
928	audio->enable = GBAudioEnableGetEnable(*audio->nr52);
929
930	LOAD_32LE(flags, 0, flagsIn);
931	LOAD_32LE(ch1Flags, 0, &state->ch1.envelope);
932	audio->ch1.envelope.currentVolume = GBSerializedAudioFlagsGetCh1Volume(flags);
933	audio->ch1.envelope.dead = GBSerializedAudioFlagsGetCh1Dead(flags);
934	audio->ch1.control.hi = GBSerializedAudioFlagsGetCh1Hi(flags);
935	audio->ch1.sweep.enable = GBSerializedAudioFlagsGetCh1SweepEnabled(flags);
936	audio->ch1.sweep.occurred = GBSerializedAudioFlagsGetCh1SweepOccurred(flags);
937	audio->ch1.control.length = GBSerializedAudioEnvelopeGetLength(ch1Flags);
938	audio->ch1.envelope.nextStep = GBSerializedAudioEnvelopeGetNextStep(ch1Flags);
939	audio->ch1.sweep.realFrequency = GBSerializedAudioEnvelopeGetFrequency(ch1Flags);
940
941	LOAD_32LE(ch2Flags, 0, &state->ch2.envelope);
942	audio->ch2.envelope.currentVolume = GBSerializedAudioFlagsGetCh2Volume(flags);
943	audio->ch2.envelope.dead = GBSerializedAudioFlagsGetCh2Dead(flags);
944	audio->ch2.control.hi = GBSerializedAudioFlagsGetCh2Hi(flags);
945	audio->ch2.control.length = GBSerializedAudioEnvelopeGetLength(ch2Flags);
946	audio->ch2.envelope.nextStep = GBSerializedAudioEnvelopeGetNextStep(ch2Flags);
947
948	audio->ch3.readable = GBSerializedAudioFlagsGetCh3Readable(flags);
949	// TODO: Big endian?
950	memcpy(audio->ch3.wavedata32, state->ch3.wavebanks, sizeof(audio->ch3.wavedata32));
951	LOAD_16LE(audio->ch3.length, 0, &state->ch3.length);
952
953	LOAD_32LE(ch4Flags, 0, &state->ch4.envelope);
954	audio->ch4.envelope.currentVolume = GBSerializedAudioFlagsGetCh4Volume(flags);
955	audio->ch4.envelope.dead = GBSerializedAudioFlagsGetCh4Dead(flags);
956	audio->ch4.length = GBSerializedAudioEnvelopeGetLength(ch4Flags);
957	audio->ch4.envelope.nextStep = GBSerializedAudioEnvelopeGetNextStep(ch4Flags);
958	LOAD_32LE(audio->ch4.lfsr, 0, &state->ch4.lfsr);
959}
960
961void GBAudioSerialize(const struct GBAudio* audio, struct GBSerializedState* state) {
962	GBAudioPSGSerialize(audio, &state->audio.psg, &state->audio.flags);
963}
964
965void GBAudioDeserialize(struct GBAudio* audio, const struct GBSerializedState* state) {
966	GBAudioPSGDeserialize(audio, &state->audio.psg, &state->audio.flags);
967}