From 034645154d41ec4586ad6cdb1906aae3f66d6fb0 Mon Sep 17 00:00:00 2001
From: Lauchmelder <robert.trololo@gmail.com>
Date: Sun, 24 Oct 2021 16:52:15 +0200
Subject: [PATCH] added interrupts

---
 NES Emulator/cpu.c | 49 +++++++++++++++++++++++++++++++++++++++++++++-
 NES Emulator/cpu.h |  6 ++++++
 NES Emulator/ppu.c |  6 ++++++
 3 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/NES Emulator/cpu.c b/NES Emulator/cpu.c
index 0ad0cd4..8ffe8bd 100644
--- a/NES Emulator/cpu.c	
+++ b/NES Emulator/cpu.c	
@@ -37,6 +37,9 @@ struct CPU* createCPU(struct Bus* parent)
 	cpu->remainingCycles = 7;
 	cpu->totalCycles = 0;
 
+	cpu->irq = 0;
+	cpu->nmi = 0;
+
 	cpu->bus = parent;
 	return cpu;
 }
@@ -54,6 +57,40 @@ int tickCPU(struct CPU* cpu)
 	cpu->remainingCycles--;
 	cpu->totalCycles += 1;
 
+	if (cpu->remainingCycles == 1)
+	{
+		// Handle interrupts
+		if (cpu->nmi)
+		{
+			Push(cpu->bus, cpu->pc.hi);
+			Push(cpu->bus, cpu->pc.lo);
+			Push(cpu->bus, cpu->status.raw & 0b11101111);
+
+			cpu->nmi = 0;
+
+			cpu->pc.lo = readBus(cpu->bus, 0xFFFA);
+			cpu->pc.hi = readBus(cpu->bus, 0xFFFB);
+
+			return 0;
+		}
+
+		if (!cpu->status.id)
+		{
+			if (cpu->irq)
+			{
+				Push(cpu->bus, cpu->pc.hi);
+				Push(cpu->bus, cpu->pc.lo);
+				Push(cpu->bus, cpu->status.raw & 0b11101111);
+
+				cpu->status.id = 1;
+				cpu->pc.lo = readBus(cpu->bus, 0xFFFE);
+				cpu->pc.hi = readBus(cpu->bus, 0xFFFF);
+
+				cpu->irq = 0;
+			}
+		}
+	}
+
 	if (cpu->remainingCycles == 0)
 	{
 		fetch(cpu);
@@ -189,7 +226,7 @@ void fetch(struct CPU* cpu)
 
 void execute(struct CPU* cpu)
 {
-	LOG_BUS(cpu->bus);
+	// LOG_BUS(cpu->bus);
 
 	switch (cpu->currentOpcode->op)
 	{
@@ -795,3 +832,13 @@ void execute(struct CPU* cpu)
 		break;
 	}
 }
+
+void IRQ(struct CPU* cpu)
+{
+	cpu->irq = 1;
+}
+
+void NMI(struct CPU* cpu)
+{
+	cpu->nmi = 1;
+}
diff --git a/NES Emulator/cpu.h b/NES Emulator/cpu.h
index b4d73e4..dec38e9 100644
--- a/NES Emulator/cpu.h	
+++ b/NES Emulator/cpu.h	
@@ -80,6 +80,9 @@ struct CPU
 	Word fetchedAddress;
 	char fetchedRelAddress;
 
+	Byte irq;
+	Byte nmi;
+
 	const struct Opcode* currentOpcode;
 
 	struct Bus* bus;
@@ -94,4 +97,7 @@ void tickInstr(struct CPU* cpu);
 void fetch(struct CPU* cpu);
 void execute(struct CPU* cpu);
 
+void IRQ(struct CPU* cpu);
+void NMI(struct CPU* cpu);
+
 #endif // _CPU_H_
\ No newline at end of file
diff --git a/NES Emulator/ppu.c b/NES Emulator/ppu.c
index 02c9ac8..0bb8c1a 100644
--- a/NES Emulator/ppu.c	
+++ b/NES Emulator/ppu.c	
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <memory.h>
 #include "bus.h"
+#include "cpu.h"
 #include "cartridge.h"
 
 struct PPU* createPPU(struct Bus* parent)
@@ -222,6 +223,11 @@ void ppuWrite(struct PPU* ppu, Word addr, Byte val)
 
 int tickPPU(struct PPU* ppu)
 {
+	// Do stuff
+	if (ppu->x == 0 && ppu->y == 241)
+		NMI(ppu->bus->cpu);
+
+	// Increment counters
 	ppu->x++;
 
 	if (ppu->x == 341)