GB Audio: Clock frame events on DIV

CHANGES

@@ -49,6 +49,7 @@ Bugfixes:
  - GBA: Fix some GBA ROM misdetection (fixes mgba.io/i/978)
  - GBA Hardware: RTC accuracy improvements
  - GB Timer: Minor accuracy improvements
+ - GB Audio: Clock frame events on DIV
 Misc:
  - GBA Timer: Use global cycles for timers
  - GBA: Extend oddly-sized ROMs to full address space (fixes mgba.io/i/722)

include/mgba/internal/gb/audio.h

@@ -232,6 +232,8 @@ void GBAudioWriteNR50(struct GBAudio* audio, uint8_t);
 void GBAudioWriteNR51(struct GBAudio* audio, uint8_t);
 void GBAudioWriteNR52(struct GBAudio* audio, uint8_t);
 
+void GBAudioUpdateFrame(struct GBAudio* audio, struct mTiming* timing);
+
 void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right);
 
 struct GBSerializedPSGState;

src/gb/audio.c

@@ -109,10 +109,12 @@ void GBAudioReset(struct GBAudio* audio) {
 	mTimingDeschedule(audio->timing, &audio->ch3Fade);
 	mTimingDeschedule(audio->timing, &audio->ch4Event);
 	mTimingDeschedule(audio->timing, &audio->sampleEvent);
-	mTimingSchedule(audio->timing, &audio->frameEvent, 0);
 	if (audio->style != GB_AUDIO_GBA) {
 		mTimingSchedule(audio->timing, &audio->sampleEvent, 0);
 	}
+	if (audio->style == GB_AUDIO_GBA) {
+		mTimingSchedule(audio->timing, &audio->frameEvent, 0);
+	}
 	audio->ch1 = (struct GBAudioSquareChannel) { .envelope = { .dead = 2 } };
 	audio->ch2 = (struct GBAudioSquareChannel) { .envelope = { .dead = 2 } };
 	audio->ch3 = (struct GBAudioWaveChannel) { .bank = 0 };
@@ -486,7 +488,13 @@ void GBAudioWriteNR52(struct GBAudio* audio, uint8_t value) {
 
 void _updateFrame(struct mTiming* timing, void* user, uint32_t cyclesLate) {
 	struct GBAudio* audio = user;
+	GBAudioUpdateFrame(audio, timing);
+	if (audio->style == GB_AUDIO_GBA) {
+		mTimingSchedule(timing, &audio->frameEvent, audio->timingFactor * FRAME_CYCLES - cyclesLate);
+	}
+}
 
+void GBAudioUpdateFrame(struct GBAudio* audio, struct mTiming* timing) {
 	int frame = (audio->frame + 1) & 7;
 	audio->frame = frame;
 
@@ -576,8 +584,6 @@ void _updateFrame(struct mTiming* timing, void* user, uint32_t cyclesLate) {
 		}
 		break;
 	}
-
-	mTimingSchedule(timing, &audio->frameEvent, audio->timingFactor * FRAME_CYCLES - cyclesLate);
 }
 
 void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right) {
@@ -959,8 +965,10 @@ void GBAudioPSGDeserialize(struct GBAudio* audio, const struct GBSerializedPSGSt
 	audio->playingCh4 = !!(*audio->nr52 & 0x0008);
 	audio->enable = GBAudioEnableGetEnable(*audio->nr52);
 
-	LOAD_32LE(when, 0, &state->ch1.nextFrame);
+	if (audio->style == GB_AUDIO_GBA) {
-	mTimingSchedule(audio->timing, &audio->frameEvent, when);
+		LOAD_32LE(when, 0, &state->ch1.nextFrame);
+		mTimingSchedule(audio->timing, &audio->frameEvent, when);
+	}
 
 	LOAD_32LE(flags, 0, flagsIn);
 	audio->frame = GBSerializedAudioFlagsGetFrame(flags);

src/gb/timer.c

@@ -30,6 +30,10 @@ static void _GBTimerDivIncrement(struct GBTimer* timer, uint32_t cyclesLate) {
 				mTimingSchedule(&timer->p->timing, &timer->irq, 7 - ((timer->p->cpu->executionState - cyclesLate) & 3));
 			}
 		}
+		int timingFactor = 0x3FF >> !timer->p->doubleSpeed;
+		if ((timer->internalDiv & timingFactor) == timingFactor) {
+			GBAudioUpdateFrame(&timer->p->audio, &timer->p->timing);
+		}
 		++timer->internalDiv;
 		timer->p->memory.io[REG_DIV] = timer->internalDiv >> 4;
 	}
@@ -76,6 +80,10 @@ void GBTimerDivReset(struct GBTimer* timer) {
 			mTimingSchedule(&timer->p->timing, &timer->irq, 7 - (timer->p->cpu->executionState & 3));
 		}
 	}
+	int timingFactor = 0x200 >> !timer->p->doubleSpeed;
+	if (timer->internalDiv & 0x200) {
+		GBAudioUpdateFrame(&timer->p->audio, &timer->p->timing);
+	}
 	timer->p->memory.io[REG_DIV] = 0;
 	timer->internalDiv = 0;
 	timer->nextDiv = GB_DMG_DIV_PERIOD;