From 2c3109e795af09dd869611fb30a2677533ec7881 Mon Sep 17 00:00:00 2001
From: Riyyi <riyyi3@gmail.com>
Date: Thu, 18 Aug 2022 14:35:24 +0200
Subject: [PATCH] Emulator: Add cycles to wait after executing opcode

---
 src/cpu.cpp | 22 ++++++++++++++++------
 src/cpu.h   |  8 +++++---
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/src/cpu.cpp b/src/cpu.cpp
index 0e632d3..d51d381 100644
--- a/src/cpu.cpp
+++ b/src/cpu.cpp
@@ -5,11 +5,13 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <cstdint> // uint8_t, uint32_t
+#include <iostream>
+
 #include "cpu.h"
 #include "emu.h"
-#include <iostream>
 
-CPU::CPU(unsigned int frequency)
+CPU::CPU(uint32_t frequency)
 	: ProcessingUnit(frequency)
 {
 }
@@ -20,17 +22,25 @@ CPU::~CPU()
 
 void CPU::update()
 {
+	m_wait_cycles--;
+	if (m_wait_cycles <= 0) {
+		// Read next opcode
+	}
+
 	printf("This is an update from the CPU\n");
 	Emu::the().writeMemory("RAM", 123, 42);
 	printf("fff");
 }
 
-void CPU::add(uint8_t byte, uint8_t immediate)
+void CPU::add(uint8_t opcode, uint8_t immediate)
 {
-	switch (byte) {
+	switch (opcode) {
 	case 0xc6: // ADD A,d8
-		// program_counter += 2;
-		// clock += 8;
+		// Program counter +2
+		m_pc += 2;
+
+		// Clock cycles +8
+		m_wait_cycles += 8;
 
 		// Flags: Z0HC
 		m_z = m_a + immediate == 0;
diff --git a/src/cpu.h b/src/cpu.h
index ba4955c..e654430 100644
--- a/src/cpu.h
+++ b/src/cpu.h
@@ -7,20 +7,20 @@
 
 #pragma once
 
-#include <cstdint> // uint8_t, uint16_t
+#include <cstdint> // int8_t, uint8_t, uint16_t, uint32_t
 
 #include "processing-unit.h"
 
 class CPU final : public ProcessingUnit {
 public:
-	CPU(unsigned int frequency);
+	explicit CPU(uint32_t frequency);
 	virtual ~CPU();
 
 	void update() override;
 
 	// 8-bit Arithmetic and Logic Instructions
 
-	void add(uint8_t byte, uint8_t immediate = 0);
+	void add(uint8_t opcode, uint8_t immediate = 0);
 
 	// 16-bit Arithmetic Instructions
 
@@ -50,4 +50,6 @@ private:
 	uint8_t m_n { 0 }; // Subtraction flag (BCD)
 	uint8_t m_h { 0 }; // Half Carry flag (BCD)
 	uint8_t m_c { 0 }; // Carry flag
+
+	int8_t m_wait_cycles { 0 };
 };