From 3fca00cb3404d6dfdb864ddd21919a2965e21fe4 Mon Sep 17 00:00:00 2001
From: Pragyansh Chaturvedi <pragyanshchaturvedi18@gmail.com>
Date: Tue, 3 Jan 2023 02:03:05 +0530
Subject: [PATCH] Make executeNextInstruction() self reliant

---
 src/cpu.cpp     | 19 ++++++++++++++++---
 src/cpu.h       | 19 +++++++++++++++----
 src/gameBoy.cpp |  7 +++++++
 src/gameBoy.h   |  4 ++++
 4 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/src/cpu.cpp b/src/cpu.cpp
index d87338a..3a842de 100644
--- a/src/cpu.cpp
+++ b/src/cpu.cpp
@@ -26,12 +26,25 @@ CPU::CPU()
 // Does nothing
 int CPU::NOP()
 {
+	reg_PC.dat += 1;
 	printf("NOP");
 	return 4;
 }
 
-int CPU::executeNextInstruction(int opcode)
+// LD BC, u16
+// Loads a 16 bit immediate value into BC
+int CPU::LD_BC_u16()
 {
-	method_function func = method_pointer[opcode];
-	return (this->*func)();
+	// Load the next 2 bytes into BC
+	
+	reg_PC.dat += 3;
+	printf("LD BC, u16");
+	return 12;
+}
+
+int CPU::executeNextInstruction()
+{
+	// Get the opcode
+	Byte opcode = *mMap[reg_PC.dat];	
+	return (this->*method_pointer[opcode])();
 }
\ No newline at end of file
diff --git a/src/cpu.h b/src/cpu.h
index 645f0ff..15c7211 100644
--- a/src/cpu.h
+++ b/src/cpu.h
@@ -1,5 +1,6 @@
 #pragma once
 #include "types.h"
+#include "mmap.h"
 
 // CPU Register
 // Pulled from https://gbdev.io/pandocs/CPU_Registers_and_Flags.html
@@ -49,12 +50,15 @@ class CPU
 		FLAG_ZERO_z = 7
 	};
 
+	// Memory Map
+	MemoryMap *mMap;
+
 	// ISA
 	// Pulled from https://izik1.github.io/gbops/index.html
 	typedef int (CPU::*method_function)();
-	method_function method_pointer[0x01] = {
-		&CPU::NOP
-		// &CPU::LD_BC_u16,
+	method_function method_pointer[0x02] = {
+		&CPU::NOP,
+		&CPU::LD_BC_u16
 		// &CPU::LD_BC_A,
 		// &CPU::INC_BC,
 		// &CPU::INC_B,
@@ -314,10 +318,17 @@ class CPU
 	// NOP
 	int NOP();
 
+	// LD nn, nn
+	int LD_BC_u16();
+
 public:
 	const int clockSpeed = 4194304; // 4.194304 MHz CPU
 	const int clockSpeedPerFrame = 70224; // 4194304 / 59.73fps
 
 	CPU();
-	int executeNextInstruction(int opcode);
+
+	// set the memory map
+	void setMemory(MemoryMap* memory) { mMap = memory; }
+
+	int executeNextInstruction();
 };
\ No newline at end of file
diff --git a/src/gameBoy.cpp b/src/gameBoy.cpp
index 43bf999..6d48521 100644
--- a/src/gameBoy.cpp
+++ b/src/gameBoy.cpp
@@ -6,6 +6,13 @@ GBE::GBE()
 {
 	// Initialize the CPU
 	gbe_cpu = new CPU();
+
+	// Initialize the MemoryMap
+	gbe_mMap = new MemoryMap();
+
+	// Unify the CPU and MemoryMap
+	gbe_cpu->setMemory(gbe_mMap);
+
 	update();
 }
 
diff --git a/src/gameBoy.h b/src/gameBoy.h
index 0f6dd85..3a78295 100644
--- a/src/gameBoy.h
+++ b/src/gameBoy.h
@@ -1,6 +1,7 @@
 #pragma once
 #include "types.h"
 #include "cpu.h"
+#include "memoryMap.h"
 
 // GBE stands for GameBoyEmulator
 
@@ -32,6 +33,9 @@ class GBE
 	// Pointer to CPU
 	CPU* gbe_cpu;
 
+	// Pointer to the MemoryMap
+	MemoryMap* gbe_mMap;
+
 	// Update function of the GBE
 	// Will be called every frame
 	// GB has 59.73 frames per second