M src/arm/arm.c → src/arm/arm.c

@@ -117,7 +117,6 @@
 	cpu->executionMode = MODE_THUMB;
 	_ARMSetMode(cpu, MODE_ARM);
 
-	cpu->currentPC = 0;
 	int currentCycles = 0;
 	ARM_WRITE_PC;
 
@@ -142,7 +141,9 @@ }
 	ARMSetPrivilegeMode(cpu, MODE_IRQ);
 	cpu->cpsr.priv = MODE_IRQ;
 	cpu->gprs[ARM_LR] = cpu->gprs[ARM_PC] - instructionWidth + WORD_SIZE_ARM;
-	cpu->gprs[ARM_PC] = BASE_IRQ + WORD_SIZE_ARM;
+	cpu->gprs[ARM_PC] = BASE_IRQ;
+	int currentCycles = 0;
+	ARM_WRITE_PC;
 	cpu->memory.setActiveRegion(cpu, cpu->gprs[ARM_PC]);
 	_ARMSetMode(cpu, MODE_ARM);
 	cpu->spsr = cpsr;
@@ -160,7 +161,9 @@ }
 	ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
 	cpu->cpsr.priv = MODE_SUPERVISOR;
 	cpu->gprs[ARM_LR] = cpu->gprs[ARM_PC] - instructionWidth;
-	cpu->gprs[ARM_PC] = BASE_SWI + WORD_SIZE_ARM;
+	cpu->gprs[ARM_PC] = BASE_SWI;
+	int currentCycles = 0;
+	ARM_WRITE_PC;
 	cpu->memory.setActiveRegion(cpu, cpu->gprs[ARM_PC]);
 	_ARMSetMode(cpu, MODE_ARM);
 	cpu->spsr = cpsr;
@@ -168,12 +171,11 @@ cpu->cpsr.i = 1;
 }
 
 static inline void ARMStep(struct ARMCore* cpu) {
-	uint32_t opcode;
-	cpu->currentPC = cpu->gprs[ARM_PC] - WORD_SIZE_ARM;
-	LOAD_32(opcode, cpu->currentPC & cpu->memory.activeMask, cpu->memory.activeRegion);
+	uint32_t opcode = cpu->prefetch;
+	LOAD_32(cpu->prefetch, cpu->gprs[ARM_PC] & cpu->memory.activeMask, cpu->memory.activeRegion);
 	cpu->gprs[ARM_PC] += WORD_SIZE_ARM;
 
-	int condition = opcode >> 28;
+	unsigned condition = opcode >> 28;
 	if (condition == 0xE) {
 		ARMInstruction instruction = _armTable[((opcode >> 16) & 0xFF0) | ((opcode >> 4) & 0x00F)];
 		instruction(cpu, opcode);
@@ -273,10 +275,9 @@ instruction(cpu, opcode);
 }
 
 static inline void ThumbStep(struct ARMCore* cpu) {
-	cpu->currentPC = cpu->gprs[ARM_PC] - WORD_SIZE_THUMB;
+	uint32_t opcode = cpu->prefetch;
+	LOAD_16(cpu->prefetch, cpu->gprs[ARM_PC] & cpu->memory.activeMask, cpu->memory.activeRegion);
 	cpu->gprs[ARM_PC] += WORD_SIZE_THUMB;
-	uint16_t opcode;
-	LOAD_16(opcode, cpu->currentPC & cpu->memory.activeMask, cpu->memory.activeRegion);
 	ThumbInstruction instruction = _thumbTable[opcode >> 6];
 	instruction(cpu, opcode);
 }

M src/arm/arm.h → src/arm/arm.h

@@ -133,7 +133,7 @@
 	int32_t shifterOperand;
 	int32_t shifterCarryOut;
 
-	uint32_t currentPC;
+	uint32_t prefetch;
 	enum ExecutionMode executionMode;
 	enum PrivilegeMode privilegeMode;
 

M src/arm/isa-inlines.h → src/arm/isa-inlines.h

@@ -44,13 +44,17 @@ #define ARM_STUB cpu->irqh.hitStub(cpu, opcode)
 #define ARM_ILL cpu->irqh.hitIllegal(cpu, opcode)
 
 #define ARM_WRITE_PC \
-	cpu->gprs[ARM_PC] = (cpu->gprs[ARM_PC] & -WORD_SIZE_ARM) + WORD_SIZE_ARM; \
-	cpu->memory.setActiveRegion(cpu, cpu->gprs[ARM_PC] - WORD_SIZE_ARM); \
+	cpu->gprs[ARM_PC] = (cpu->gprs[ARM_PC] & -WORD_SIZE_ARM); \
+	cpu->memory.setActiveRegion(cpu, cpu->gprs[ARM_PC]); \
+	LOAD_32(cpu->prefetch, cpu->gprs[ARM_PC] & cpu->memory.activeMask, cpu->memory.activeRegion); \
+	cpu->gprs[ARM_PC] += WORD_SIZE_ARM; \
 	currentCycles += 2 + cpu->memory.activeUncachedCycles32 + cpu->memory.activeSeqCycles32;
 
 #define THUMB_WRITE_PC \
-	cpu->gprs[ARM_PC] = (cpu->gprs[ARM_PC] & -WORD_SIZE_THUMB) + WORD_SIZE_THUMB; \
-	cpu->memory.setActiveRegion(cpu, cpu->gprs[ARM_PC] - WORD_SIZE_THUMB); \
+	cpu->gprs[ARM_PC] = (cpu->gprs[ARM_PC] & -WORD_SIZE_THUMB); \
+	cpu->memory.setActiveRegion(cpu, cpu->gprs[ARM_PC]); \
+	LOAD_16(cpu->prefetch, cpu->gprs[ARM_PC] & cpu->memory.activeMask, cpu->memory.activeRegion); \
+	cpu->gprs[ARM_PC] += WORD_SIZE_THUMB; \
 	currentCycles += 2 + cpu->memory.activeUncachedCycles16 + cpu->memory.activeSeqCycles16;
 
 static inline int _ARMModeHasSPSR(enum PrivilegeMode mode) {

M src/gba/gba-memory.c → src/gba/gba-memory.c

@@ -109,16 +109,12 @@ static void GBASetActiveRegion(struct ARMCore* cpu, uint32_t address) {
 	struct GBA* gba = (struct GBA*) cpu->master;
 	struct GBAMemory* memory = &gba->memory;
 
-	if (cpu->currentPC == gba->busyLoop) {
-		GBAHalt(gba);
-	}
-
 	int newRegion = address >> BASE_OFFSET;
 	if (newRegion == memory->activeRegion) {
 		return;
 	}
 	if (memory->activeRegion == REGION_BIOS) {
-		memory->biosPrefetch = cpu->memory.load32(cpu, cpu->currentPC + WORD_SIZE_ARM * 2, 0);
+		memory->biosPrefetch = cpu->prefetch;
 	}
 	memory->activeRegion = newRegion;
 	switch (address & ~OFFSET_MASK) {
@@ -165,7 +161,7 @@ int wait = 0;
 
 	switch (address & ~OFFSET_MASK) {
 	case BASE_BIOS:
-		if (cpu->currentPC >> BASE_OFFSET == REGION_BIOS) {
+		if (cpu->gprs[ARM_PC] >> BASE_OFFSET == REGION_BIOS) {
 			if (address < SIZE_BIOS) {
 				LOAD_32(value, address, memory->bios);
 			} else {
@@ -211,10 +207,8 @@ GBALog(gba, GBA_LOG_STUB, "Unimplemented memory Load32: 0x%08X", address);
 		break;
 	default:
 		GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load32: 0x%08X", address);
-		if (cpu->executionMode == MODE_ARM) {
-			value = cpu->memory.load32(cpu, cpu->currentPC + WORD_SIZE_ARM * 2, 0);
-		} else {
-			value = cpu->memory.load16(cpu, cpu->currentPC + WORD_SIZE_THUMB * 2, 0);
+		value = cpu->prefetch;
+		if (cpu->executionMode == MODE_THUMB) {
 			value |= value << 16;
 		}
 		break;
@@ -241,7 +235,7 @@ int wait = 0;
 
 	switch (address & ~OFFSET_MASK) {
 	case BASE_BIOS:
-		if (cpu->currentPC >> BASE_OFFSET == REGION_BIOS) {
+		if (cpu->gprs[ARM_PC] >> BASE_OFFSET == REGION_BIOS) {
 			if (address < SIZE_BIOS) {
 				LOAD_16(value, address, memory->bios);
 			} else {
@@ -294,7 +288,7 @@ GBALog(gba, GBA_LOG_STUB, "Unimplemented memory Load16: 0x%08X", address);
 		break;
 	default:
 		GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load16: 0x%08X", address);
-		value = cpu->memory.load16(cpu, cpu->currentPC + (cpu->executionMode == MODE_ARM ? WORD_SIZE_ARM : WORD_SIZE_THUMB) * 2, 0);
+		value = cpu->prefetch;
 		break;
 	}
 
@@ -318,7 +312,7 @@ int wait = 0;
 
 	switch (address & ~OFFSET_MASK) {
 	case BASE_BIOS:
-		if (cpu->currentPC >> BASE_OFFSET == REGION_BIOS) {
+		if (cpu->gprs[ARM_PC] >> BASE_OFFSET == REGION_BIOS) {
 			if (address < SIZE_BIOS) {
 				value = ((int8_t*) memory->bios)[address];
 			} else {
@@ -372,7 +366,7 @@ }
 		break;
 	default:
 		GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load8: 0x%08x", address);
-		value = cpu->memory.load16(cpu, cpu->currentPC + (cpu->executionMode == MODE_ARM ? WORD_SIZE_ARM : WORD_SIZE_THUMB) * 2, 0) >> ((address & 1) << 3);
+		value = cpu->prefetch & 0xFF;
 		break;
 	}