GBA Memory: Fix DMA register writing behavior (fixes #148)

CHANGES

@@ -7,13 +7,13 @@ Features:
 Bugfixes:
  - Util: Fix PowerPC PNG read/write pixel order
  - Qt: Use safer isLoaded check in GameController
- - GBA Memory: Fix DMAs from BIOS while not in BIOS
  - GBA: Fix idle skip state being retained between games
  - Qt: Fix a race condition in PainterGL that could lead to a crash
  - Qt: Fix clear button/analog buttons in gamepad mapper on some platforms
  - GBA Video: Fix _mix for 15-bit color
  - VFS: Fix VFileReadline and remove _vfdReadline
  - Qt: Fix font size in memory viewer
+ - GBA Memory: Fix DMA register writing behavior
 Misc:
  - Qt: Window size command line options are now supported
  - Qt: Increase usability of key mapper

src/gba/io.c

@@ -535,28 +535,28 @@ void GBAIOWrite32(struct GBA* gba, uint32_t address, uint32_t value) {
 		GBAAudioWriteFIFO(&gba->audio, address, value);
 		break;
 	case REG_DMA0SAD_LO:
-		GBAMemoryWriteDMASAD(gba, 0, value);
+		value = GBAMemoryWriteDMASAD(gba, 0, value);
 		break;
 	case REG_DMA0DAD_LO:
-		GBAMemoryWriteDMADAD(gba, 0, value);
+		value = GBAMemoryWriteDMADAD(gba, 0, value);
 		break;
 	case REG_DMA1SAD_LO:
-		GBAMemoryWriteDMASAD(gba, 1, value);
+		value = GBAMemoryWriteDMASAD(gba, 1, value);
 		break;
 	case REG_DMA1DAD_LO:
-		GBAMemoryWriteDMADAD(gba, 1, value);
+		value = GBAMemoryWriteDMADAD(gba, 1, value);
 		break;
 	case REG_DMA2SAD_LO:
-		GBAMemoryWriteDMASAD(gba, 2, value);
+		value = GBAMemoryWriteDMASAD(gba, 2, value);
 		break;
 	case REG_DMA2DAD_LO:
-		GBAMemoryWriteDMADAD(gba, 2, value);
+		value = GBAMemoryWriteDMADAD(gba, 2, value);
 		break;
 	case REG_DMA3SAD_LO:
-		GBAMemoryWriteDMASAD(gba, 3, value);
+		value = GBAMemoryWriteDMASAD(gba, 3, value);
 		break;
 	case REG_DMA3DAD_LO:
-		GBAMemoryWriteDMADAD(gba, 3, value);
+		value = GBAMemoryWriteDMADAD(gba, 3, value);
 		break;
 	default:
 		GBAIOWrite(gba, address, value & 0xFFFF);

src/gba/memory.c

@@ -330,13 +330,8 @@ static void GBASetActiveRegion(struct ARMCore* cpu, uint32_t address) {
 			LOAD_32(value, address, memory->bios); \
 		} else { \
 			GBALog(gba, GBA_LOG_GAME_ERROR, "Bad BIOS Load32: 0x%08X", address); \
-			if (memory->activeDMA) { \
-				/* TODO: Test on hardware */ \
-				value = 0; \
-			} else { \
 			value = memory->biosPrefetch; \
 		} \
-		} \
 	} else { \
 		GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load32: 0x%08X", address); \
 		LOAD_BAD; \
@@ -451,12 +446,8 @@ uint32_t GBALoad16(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
 				LOAD_16(value, address, memory->bios);
 			} else {
 				GBALog(gba, GBA_LOG_GAME_ERROR, "Bad BIOS Load16: 0x%08X", address);
-				if (memory->activeDMA) {
-					value = 0;
-				} else {
 				value = (memory->biosPrefetch >> ((address & 2) * 8)) & 0xFFFF;
 			}
-			}
 		} else {
 			GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load16: 0x%08X", address);
 			LOAD_BAD;
@@ -1320,15 +1311,21 @@ void GBAAdjustWaitstates(struct GBA* gba, uint16_t parameters) {
 	cpu->memory.activeNonseqCycles16 = memory->waitstatesNonseq16[memory->activeRegion];
 }
 
-void GBAMemoryWriteDMASAD(struct GBA* gba, int dma, uint32_t address) {
+uint32_t GBAMemoryWriteDMASAD(struct GBA* gba, int dma, uint32_t address) {
 	struct GBAMemory* memory = &gba->memory;
+	if ((dma >= 1 || address < BASE_CART0) && address >= BASE_WORKING_RAM && address < BASE_CART_SRAM) {
 		memory->dma[dma].source = address & 0x0FFFFFFE;
 	}
+	return memory->dma[dma].source;
+}
 
-void GBAMemoryWriteDMADAD(struct GBA* gba, int dma, uint32_t address) {
+uint32_t GBAMemoryWriteDMADAD(struct GBA* gba, int dma, uint32_t address) {
 	struct GBAMemory* memory = &gba->memory;
+	if ((dma >= 1 || address < BASE_CART0) && address >= BASE_WORKING_RAM && address < BASE_CART_SRAM) {
 		memory->dma[dma].dest = address & 0x0FFFFFFE;
 	}
+	return memory->dma[dma].dest;
+}
 
 void GBAMemoryWriteDMACNT_LO(struct GBA* gba, int dma, uint16_t count) {
 	struct GBAMemory* memory = &gba->memory;

src/gba/memory.h

@@ -166,8 +166,8 @@ uint32_t GBAStoreMultiple(struct ARMCore*, uint32_t baseAddress, int mask, enum
 
 void GBAAdjustWaitstates(struct GBA* gba, uint16_t parameters);
 
-void GBAMemoryWriteDMASAD(struct GBA* gba, int dma, uint32_t address);
+uint32_t GBAMemoryWriteDMASAD(struct GBA* gba, int dma, uint32_t address);
-void GBAMemoryWriteDMADAD(struct GBA* gba, int dma, uint32_t address);
+uint32_t GBAMemoryWriteDMADAD(struct GBA* gba, int dma, uint32_t address);
 void GBAMemoryWriteDMACNT_LO(struct GBA* gba, int dma, uint16_t count);
 uint16_t GBAMemoryWriteDMACNT_HI(struct GBA* gba, int dma, uint16_t control);