M CHANGES → CHANGES

@@ -5,6 +5,7 @@ - ARM: Fix STR storing PC after address calculation
  - GBA DMA: Linger last DMA on bus (fixes mgba.io/i/301 and mgba.io/i/1320)
  - GBA Memory: Misaligned SRAM writes are ignored
  - GBA Serialize: Fix serializing DMA transfer register
+ - GBA Serialize: Fix audio serialization for desynced FIFOs
 Other fixes:
  - Qt: Only dynamically reset video scale if a game is running
  - Qt: Fix race condition with proxied video events

M include/mgba/internal/gba/serialize.h → include/mgba/internal/gba/serialize.h

@@ -66,9 +66,10 @@ * | 0x00188 - 0x0018B: Next event
  * 0x0018C - 0x001AB: Audio FIFO 1
  * 0x001AC - 0x001CB: Audio FIFO 2
  * 0x001CC - 0x001DF: Audio miscellaneous state
- * | 0x001CC - 0x001D3: Reserved
+ * | 0x001CC - 0x001CF: FIFO 1 size
+ * | 0x001D0 - 0x001D3: Reserved
  * | 0x001D4 - 0x001D7: Next sample
- * | 0x001D8 - 0x001DB: FIFO size
+ * | 0x001D8 - 0x001DB: FIFO 2 size
  * | TODO: Fix this, they're in big-endian order, but field is little-endian
  * | 0x001DC - 0x001DC: Channel 1 envelope state
  *   | bits 0 - 3: Current volume
@@ -170,7 +171,8 @@ *   | bits 4 - 8: GB Player transmit position
  *   | bits 9 - 23: Reserved
  * 0x002C4 - 0x002C7: Game Boy Player next event
  * 0x002C8 - 0x002CB: Current DMA transfer word
- * 0x002CC - 0x002DF: Reserved (leave zero)
+ * 0x002CC - 0x002CF: Last DMA transfer PC
+ * 0x002D0 - 0x002DF: Reserved (leave zero)
  * 0x002E0 - 0x002EF: Savedata state
  * | 0x002E0 - 0x002E0: Savedata type
  * | 0x002E1 - 0x002E1: Savedata command (see savedata.h)
@@ -256,9 +258,10 @@ struct {
 		struct GBSerializedPSGState psg;
 		uint8_t fifoA[32];
 		uint8_t fifoB[32];
-		int32_t reserved[2];
+		uint32_t fifoSizeA;
+		int32_t reserved;
 		int32_t nextSample;
-		uint32_t fifoSize;
+		uint32_t fifoSizeB;
 		GBSerializedAudioFlags flags;
 	} audio;
 

M src/gba/audio.c → src/gba/audio.c

@@ -348,7 +348,9 @@
 	CircleBufferDump(&audio->chA.fifo, state->audio.fifoA, sizeof(state->audio.fifoA));
 	CircleBufferDump(&audio->chB.fifo, state->audio.fifoB, sizeof(state->audio.fifoB));
 	uint32_t fifoSize = CircleBufferSize(&audio->chA.fifo);
-	STORE_32(fifoSize, 0, &state->audio.fifoSize);
+	STORE_32(fifoSize, 0, &state->audio.fifoSizeA);
+	fifoSize = CircleBufferSize(&audio->chB.fifo);
+	STORE_32(fifoSize, 0, &state->audio.fifoSizeB);
 	STORE_32(audio->sampleEvent.when - mTimingCurrentTime(&audio->p->timing), 0, &state->audio.nextSample);
 }
 
@@ -358,13 +360,20 @@
 	CircleBufferClear(&audio->chA.fifo);
 	CircleBufferClear(&audio->chB.fifo);
 	uint32_t fifoSize;
-	LOAD_32(fifoSize, 0, &state->audio.fifoSize);
-	if (state->audio.fifoSize > CircleBufferCapacity(&audio->chA.fifo)) {
+	LOAD_32(fifoSize, 0, &state->audio.fifoSizeA);
+	if (fifoSize > CircleBufferCapacity(&audio->chA.fifo)) {
 		fifoSize = CircleBufferCapacity(&audio->chA.fifo);
 	}
 	size_t i;
 	for (i = 0; i < fifoSize; ++i) {
 		CircleBufferWrite8(&audio->chA.fifo, state->audio.fifoA[i]);
+	}
+
+	LOAD_32(fifoSize, 0, &state->audio.fifoSizeB);
+	if (fifoSize > CircleBufferCapacity(&audio->chB.fifo)) {
+		fifoSize = CircleBufferCapacity(&audio->chB.fifo);
+	}
+	for (i = 0; i < fifoSize; ++i) {
 		CircleBufferWrite8(&audio->chB.fifo, state->audio.fifoB[i]);
 	}