M CHANGES → CHANGES

@@ -10,6 +10,7 @@ - ARM: Fix ALU reading PC after shifting
  - ARM: Fix STR storing PC after address calculation
  - GB: Partially fix timing for skipped BIOS
  - GB Audio: Fix initial sweep state
+ - GB Audio: Fix serializing sweep time
  - GB MBC: Fix MBC1 mode changing behavior
  - GB Video: Fix state after skipping BIOS (fixes mgba.io/i/1715 and mgba.io/i/1716)
  - GBA: Fix timing advancing too quickly in rare cases

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

@@ -59,7 +59,9 @@ *   | bits 10 - 20: Shadow frequency register
  *   | bits 21 - 31: Reserved
  * | 0x0004C - 0x0004F: Next frame
  * | 0x00050 - 0x00053: Next channel 3 fade
- * | 0x00054 - 0x00057: Reserved
+ * | 0x00054 - 0x00057: Sweep state
+ *   | bits 0 - 2: Timesteps
+ *   | bits 3 - 31: Reserved
  * | 0x00058 - 0x0005B: Next event
  * 0x0005C - 0x0006B: Audio channel 2 state
  * | 0x0005C - 0x0005F: Envelepe timing
@@ -87,22 +89,23 @@ * | 0x000A4: Channel 1 envelope state
  *   | bits 0 - 3: Current volume
  *   | bits 4 - 5: Is dead?
  *   | bit 6: Is high?
+*    | bit 7: Reserved
  * | 0x000A5: Channel 2 envelope state
  *   | bits 0 - 3: Current volume
  *   | bits 4 - 5: Is dead?
  *   | bit 6: Is high?
-*    | bits 7: Reserved
+*    | bit 7: Reserved
  * | 0x000A6: Channel 4 envelope state
  *   | bits 0 - 3: Current volume
  *   | bits 4 - 5: Is dead?
- *   | bit 6: Is high?
-*    | bits 7: Reserved
+ *   | bits 6 - 7: Current frame (continued)
  * | 0x000A7: Miscellaneous audio flags
- *   | bits 0 - 3: Current frame
- *   | bit 4: Is channel 1 sweep enabled?
- *   | bit 5: Has channel 1 sweep occurred?
- *   | bit 6: Is channel 3's memory readable?
- *   | bit 7: Reserved
+ *   | bit 0: Current frame (continuation)
+ *   | bit 1: Is channel 1 sweep enabled?
+ *   | bit 2: Has channel 1 sweep occurred?
+ *   | bit 3: Is channel 3's memory readable?
+ *   | bit 4: Skip frame
+ *   | bits 5 - 7: Reserved
  * | 0x000A8 - 0x000AB: Left capacitor charge
  * | 0x000AC - 0x000AF: Right capacitor charge
  * | 0x000B0 - 0x000B3: Next sample
@@ -203,12 +206,16 @@ DECL_BITS(GBSerializedAudioEnvelope, Length, 0, 7);
 DECL_BITS(GBSerializedAudioEnvelope, NextStep, 7, 3);
 DECL_BITS(GBSerializedAudioEnvelope, Frequency, 10, 11);
 
+
+DECL_BITFIELD(GBSerializedAudioSweep, uint32_t);
+DECL_BITS(GBSerializedAudioSweep, Time, 0, 3);
+
 struct GBSerializedPSGState {
 	struct {
 		GBSerializedAudioEnvelope envelope;
 		int32_t nextFrame;
 		int32_t nextCh3Fade;
-		int32_t reserved;
+		GBSerializedAudioSweep sweep;
 		uint32_t nextEvent;
 	} ch1;
 	struct {

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

@@ -41,7 +41,10 @@ *   | bits 7 - 9: Next step
  *   | bits 10 - 20: Shadow frequency register
  *   | bits 21 - 31: Reserved
  * | 0x00134 - 0x00137: Next frame
- * | 0x00138 - 0x0013F: Reserved
+ * | 0x00138 - 0x0013B: Next channel 3 fade
+ * | 0x0013C - 0x0013F: Sweep state
+ *   | bits 0 - 2: Timesteps
+ *   | bits 3 - 7: Reserved
  * | 0x00140 - 0x00143: Next event
  * 0x00144 - 0x00153: Audio channel 2 state
  * | 0x00144 - 0x00147: Envelepe timing
@@ -75,21 +78,23 @@ * | 0x001DC - 0x001DC: Channel 1 envelope state
  *   | bits 0 - 3: Current volume
  *   | bits 4 - 5: Is dead?
  *   | bit 6: Is high?
+*    | bit 7: Reserved
  * | 0x001DD - 0x001DD: Channel 2 envelope state
  *   | bits 0 - 3: Current volume
  *   | bits 4 - 5: Is dead?
  *   | bit 6: Is high?
-*    | bits 7: Reserved
+*    | bit 7: Reserved
  * | 0x001DE - 0x001DE: Channel 4 envelope state
  *   | bits 0 - 3: Current volume
  *   | bits 4 - 5: Is dead?
- *   | bit 6: Is high?
-*    | bits 7: Reserved
+ *   | bits 6 - 7: Current frame (continued)
  * | 0x001DF - 0x001DF: Miscellaneous audio flags
- *   | bits 0 - 3: Current frame
- *   | bit 4: Is channel 1 sweep enabled?
- *   | bit 5: Has channel 1 sweep occurred?
- *   | bits 6 - 7: Reserved
+ *   | bit 0: Current frame (continuation)
+ *   | bit 1: Is channel 1 sweep enabled?
+ *   | bit 2: Has channel 1 sweep occurred?
+ *   | bit 3: Is channel 3's memory readable?
+ *   | bit 4: Skip frame
+ *   | bits 5 - 7: Reserved
  * 0x001E0 - 0x001FF: Video miscellaneous state
  * | 0x001E0 - 0x001E3: Next event
  * | 0x001E4 - 0x001F7: Reserved

M src/gb/audio.c → src/gb/audio.c

@@ -964,6 +964,7 @@ }
 
 void GBAudioPSGSerialize(const struct GBAudio* audio, struct GBSerializedPSGState* state, uint32_t* flagsOut) {
 	uint32_t flags = 0;
+	uint32_t sweep = 0;
 	uint32_t ch1Flags = 0;
 	uint32_t ch2Flags = 0;
 	uint32_t ch4Flags = 0;
@@ -980,7 +981,9 @@ flags = GBSerializedAudioFlagsSetCh1SweepOccurred(flags, audio->ch1.sweep.occurred);
 	ch1Flags = GBSerializedAudioEnvelopeSetLength(ch1Flags, audio->ch1.control.length);
 	ch1Flags = GBSerializedAudioEnvelopeSetNextStep(ch1Flags, audio->ch1.envelope.nextStep);
 	ch1Flags = GBSerializedAudioEnvelopeSetFrequency(ch1Flags, audio->ch1.sweep.realFrequency);
+	sweep = GBSerializedAudioSweepSetTime(sweep, audio->ch1.sweep.time & 7);
 	STORE_32LE(ch1Flags, 0, &state->ch1.envelope);
+	STORE_32LE(sweep, 0, &state->ch1.sweep);
 	STORE_32LE(audio->ch1Event.when - mTimingCurrentTime(audio->timing), 0, &state->ch1.nextEvent);
 
 	flags = GBSerializedAudioFlagsSetCh2Volume(flags, audio->ch2.envelope.currentVolume);
@@ -1011,6 +1014,7 @@ }
 
 void GBAudioPSGDeserialize(struct GBAudio* audio, const struct GBSerializedPSGState* state, const uint32_t* flagsIn) {
 	uint32_t flags;
+	uint32_t sweep;
 	uint32_t ch1Flags = 0;
 	uint32_t ch2Flags = 0;
 	uint32_t ch4Flags = 0;
@@ -1032,11 +1036,16 @@ audio->frame = GBSerializedAudioFlagsGetFrame(flags);
 	audio->skipFrame = GBSerializedAudioFlagsGetSkipFrame(flags);
 
 	LOAD_32LE(ch1Flags, 0, &state->ch1.envelope);
+	LOAD_32LE(sweep, 0, &state->ch1.sweep);
 	audio->ch1.envelope.currentVolume = GBSerializedAudioFlagsGetCh1Volume(flags);
 	audio->ch1.envelope.dead = GBSerializedAudioFlagsGetCh1Dead(flags);
 	audio->ch1.control.hi = GBSerializedAudioFlagsGetCh1Hi(flags);
 	audio->ch1.sweep.enable = GBSerializedAudioFlagsGetCh1SweepEnabled(flags);
 	audio->ch1.sweep.occurred = GBSerializedAudioFlagsGetCh1SweepOccurred(flags);
+	audio->ch1.sweep.time = GBSerializedAudioSweepGetTime(sweep);
+	if (!audio->ch1.sweep.time) {
+		audio->ch1.sweep.time = 8;
+	}
 	audio->ch1.control.length = GBSerializedAudioEnvelopeGetLength(ch1Flags);
 	audio->ch1.envelope.nextStep = GBSerializedAudioEnvelopeGetNextStep(ch1Flags);
 	audio->ch1.sweep.realFrequency = GBSerializedAudioEnvelopeGetFrequency(ch1Flags);