all repos — mgba @ da62e772a423de9e1b04a309047cc202058de7f7

mGBA Game Boy Advance Emulator

LR35902: Fix IRQ timing
Jeffrey Pfau jeffrey@endrift.com
Wed, 27 Jan 2016 21:42:06 -0800
commit

da62e772a423de9e1b04a309047cc202058de7f7

parent

213ba2996479391de53af8cca42f48820ce75d69

1 files changed, 14 insertions(+), 5 deletions(-)

jump to
M src/lr35902/lr35902.c → src/lr35902/lr35902.c 
@@ -75,11 +75,20 @@ cpu->irqPending = true;
 	cpu->irqVector = vector;
 }
 
+static void _LR35902InstructionIRQStall(struct LR35902Core* cpu) {
+	cpu->executionState = LR35902_CORE_STALL;
+}
+
 static void _LR35902InstructionIRQFinish(struct LR35902Core* cpu) {
+	cpu->executionState = LR35902_CORE_OP2;
+	cpu->instruction = _LR35902InstructionIRQStall;
+}
+
+static void _LR35902InstructionIRQDelay(struct LR35902Core* cpu) {
 	cpu->index = cpu->sp + 1;
 	cpu->bus = cpu->pc >> 8;
 	cpu->executionState = LR35902_CORE_MEMORY_STORE;
-	cpu->instruction = _lr35902InstructionTable[0]; // NOP
+	cpu->instruction = _LR35902InstructionIRQFinish;
 	cpu->pc = cpu->irqVector;
 	cpu->memory.setActiveRegion(cpu, cpu->pc);
 }

@@ -89,11 +98,11 @@ cpu->sp -= 2; /* TODO: Atomic incrementing? */
 	cpu->index = cpu->sp;
 	cpu->bus = cpu->pc;
 	cpu->executionState = LR35902_CORE_MEMORY_STORE;
-	cpu->instruction = _LR35902InstructionIRQFinish;
+	cpu->instruction = _LR35902InstructionIRQDelay;
 	cpu->irqh.setInterrupts(cpu, false);
 }
 
-static void _lr35902Step(struct LR35902Core* cpu) {
+static void _LR35902Step(struct LR35902Core* cpu) {
 	++cpu->cycles;
 	enum LR35902ExecutionState state = cpu->executionState;
 	++cpu->executionState;

@@ -132,7 +141,7 @@ }
 }
 
 void LR35902Tick(struct LR35902Core* cpu) {
-	_lr35902Step(cpu);
+	_LR35902Step(cpu);
 	if (cpu->cycles >= cpu->nextEvent) {
 		cpu->irqh.processEvents(cpu);
 	}

@@ -140,7 +149,7 @@ }
 
 void LR35902Run(struct LR35902Core* cpu) {
 	while (cpu->cycles < cpu->nextEvent) {
-		_lr35902Step(cpu);
+		_LR35902Step(cpu);
 	}
 	cpu->irqh.processEvents(cpu);
 }