#include <iostream>
#include <cstring>
#include "CPU.hpp"
#include "NES.hpp"


const unsigned int STACK_START_ADDRESS = 0x100u;
const unsigned int NMI_VECTOR_LSB = 0xFFFAu;
const unsigned int NMI_VECTOR_MSB = 0xFFFBu;
const unsigned int RESET_VECTOR_LSB = 0xFFFCu;
const unsigned int RESET_VECTOR_MSB = 0xFFFDu;

CPU::CPU()
{
	status.SetByte(0x24);

	instructions[0xA9] = Instruction{.name = "LDA", .cycles = 2, .execute = &CPU::LDA, .fetch = &CPU::Immediate};
	instructions[0xA5] = Instruction{.name = "LDA", .cycles = 3, .execute = &CPU::LDA, .fetch = &CPU::ZeroPage};
	instructions[0xB5] = Instruction{.name = "LDA", .cycles = 4, .execute = &CPU::LDA, .fetch = &CPU::ZeroPageX};
	instructions[0xAD] = Instruction{.name = "LDA", .cycles = 4, .execute = &CPU::LDA, .fetch = &CPU::Absolute};
	instructions[0xBD] = Instruction{.name = "LDA", .cycles = 4, .execute = &CPU::LDA, .fetch = &CPU::AbsoluteX};
	instructions[0xB9] = Instruction{.name = "LDA", .cycles = 4, .execute = &CPU::LDA, .fetch = &CPU::AbsoluteY};
	instructions[0xA1] = Instruction{.name = "LDA", .cycles = 6, .execute = &CPU::LDA, .fetch = &CPU::IndirectX};
	instructions[0xB1] = Instruction{.name = "LDA", .cycles = 5, .execute = &CPU::LDA, .fetch = &CPU::IndirectY};

	instructions[0xA2] = Instruction{.name = "LDX", .cycles = 2, .execute = &CPU::LDX, .fetch = &CPU::Immediate};
	instructions[0xA6] = Instruction{.name = "LDX", .cycles = 3, .execute = &CPU::LDX, .fetch = &CPU::ZeroPage};
	instructions[0xB6] = Instruction{.name = "LDX", .cycles = 4, .execute = &CPU::LDX, .fetch = &CPU::ZeroPageY};
	instructions[0xAE] = Instruction{.name = "LDX", .cycles = 4, .execute = &CPU::LDX, .fetch = &CPU::Absolute};
	instructions[0xBE] = Instruction{.name = "LDX", .cycles = 4, .execute = &CPU::LDX, .fetch = &CPU::AbsoluteY};

	instructions[0xA0] = Instruction{.name = "LDY", .cycles = 2, .execute = &CPU::LDY, .fetch = &CPU::Immediate};
	instructions[0xA4] = Instruction{.name = "LDY", .cycles = 3, .execute = &CPU::LDY, .fetch = &CPU::ZeroPage};
	instructions[0xB4] = Instruction{.name = "LDY", .cycles = 4, .execute = &CPU::LDY, .fetch = &CPU::ZeroPageX};
	instructions[0xAC] = Instruction{.name = "LDY", .cycles = 4, .execute = &CPU::LDY, .fetch = &CPU::Absolute};
	instructions[0xBC] = Instruction{.name = "LDY", .cycles = 4, .execute = &CPU::LDY, .fetch = &CPU::AbsoluteX};

	instructions[0x85] = Instruction{.name = "STA", .cycles = 3, .execute = &CPU::STA, .fetch = &CPU::ZeroPage};
	instructions[0x95] = Instruction{.name = "STA", .cycles = 4, .execute = &CPU::STA, .fetch = &CPU::ZeroPageX};
	instructions[0x8D] = Instruction{.name = "STA", .cycles = 4, .execute = &CPU::STA, .fetch = &CPU::Absolute};
	instructions[0x9D] = Instruction{.name = "STA", .cycles = 5, .execute = &CPU::STA, .fetch = &CPU::AbsoluteX};
	instructions[0x99] = Instruction{.name = "STA", .cycles = 5, .execute = &CPU::STA, .fetch = &CPU::AbsoluteY};
	instructions[0x81] = Instruction{.name = "STA", .cycles = 6, .execute = &CPU::STA, .fetch = &CPU::IndirectX};
	instructions[0x91] = Instruction{.name = "STA", .cycles = 6, .execute = &CPU::STA, .fetch = &CPU::IndirectY};

	instructions[0x86] = Instruction{.name = "STX", .cycles = 3, .execute = &CPU::STX, .fetch = &CPU::ZeroPage};
	instructions[0x96] = Instruction{.name = "STX", .cycles = 4, .execute = &CPU::STX, .fetch = &CPU::ZeroPageY};
	instructions[0x8E] = Instruction{.name = "STX", .cycles = 4, .execute = &CPU::STX, .fetch = &CPU::Absolute};

	instructions[0x84] = Instruction{.name = "STY", .cycles = 3, .execute = &CPU::STY, .fetch = &CPU::ZeroPage};
	instructions[0x94] = Instruction{.name = "STY", .cycles = 4, .execute = &CPU::STY, .fetch = &CPU::ZeroPageX};
	instructions[0x8C] = Instruction{.name = "STY", .cycles = 4, .execute = &CPU::STY, .fetch = &CPU::Absolute};

	instructions[0xAA] = Instruction{.name = "TAX", .cycles = 2, .execute = &CPU::TAX, .fetch = &CPU::Implicit};
	instructions[0xA8] = Instruction{.name = "TAY", .cycles = 2, .execute = &CPU::TAY, .fetch = &CPU::Implicit};
	instructions[0x8A] = Instruction{.name = "TXA", .cycles = 2, .execute = &CPU::TXA, .fetch = &CPU::Implicit};
	instructions[0x98] = Instruction{.name = "TYA", .cycles = 2, .execute = &CPU::TYA, .fetch = &CPU::Implicit};
	instructions[0xBA] = Instruction{.name = "TSX", .cycles = 2, .execute = &CPU::TSX, .fetch = &CPU::Implicit};
	instructions[0x9A] = Instruction{.name = "TXS", .cycles = 2, .execute = &CPU::TXS, .fetch = &CPU::Implicit};

	instructions[0x48] = Instruction{.name = "PHA", .cycles = 3, .execute = &CPU::PHA, .fetch = &CPU::Implicit};
	instructions[0x08] = Instruction{.name = "PHP", .cycles = 3, .execute = &CPU::PHP, .fetch = &CPU::Implicit};
	instructions[0x68] = Instruction{.name = "PLA", .cycles = 4, .execute = &CPU::PLA, .fetch = &CPU::Implicit};
	instructions[0x28] = Instruction{.name = "PLP", .cycles = 4, .execute = &CPU::PLP, .fetch = &CPU::Implicit};

	instructions[0x29] = Instruction{.name = "AND", .cycles = 2, .execute = &CPU::AND, .fetch = &CPU::Immediate};
	instructions[0x25] = Instruction{.name = "AND", .cycles = 3, .execute = &CPU::AND, .fetch = &CPU::ZeroPage};
	instructions[0x35] = Instruction{.name = "AND", .cycles = 4, .execute = &CPU::AND, .fetch = &CPU::ZeroPageX};
	instructions[0x2D] = Instruction{.name = "AND", .cycles = 4, .execute = &CPU::AND, .fetch = &CPU::Absolute};
	instructions[0x3D] = Instruction{.name = "AND", .cycles = 4, .execute = &CPU::AND, .fetch = &CPU::AbsoluteX};
	instructions[0x39] = Instruction{.name = "AND", .cycles = 4, .execute = &CPU::AND, .fetch = &CPU::AbsoluteY};
	instructions[0x21] = Instruction{.name = "AND", .cycles = 6, .execute = &CPU::AND, .fetch = &CPU::IndirectX};
	instructions[0x31] = Instruction{.name = "AND", .cycles = 5, .execute = &CPU::AND, .fetch = &CPU::IndirectY};

	instructions[0x49] = Instruction{.name = "EOR", .cycles = 2, .execute = &CPU::EOR, .fetch = &CPU::Immediate};
	instructions[0x45] = Instruction{.name = "EOR", .cycles = 3, .execute = &CPU::EOR, .fetch = &CPU::ZeroPage};
	instructions[0x55] = Instruction{.name = "EOR", .cycles = 4, .execute = &CPU::EOR, .fetch = &CPU::ZeroPageX};
	instructions[0x4D] = Instruction{.name = "EOR", .cycles = 4, .execute = &CPU::EOR, .fetch = &CPU::Absolute};
	instructions[0x5D] = Instruction{.name = "EOR", .cycles = 4, .execute = &CPU::EOR, .fetch = &CPU::AbsoluteX};
	instructions[0x59] = Instruction{.name = "EOR", .cycles = 4, .execute = &CPU::EOR, .fetch = &CPU::AbsoluteY};
	instructions[0x41] = Instruction{.name = "EOR", .cycles = 6, .execute = &CPU::EOR, .fetch = &CPU::IndirectX};
	instructions[0x51] = Instruction{.name = "EOR", .cycles = 5, .execute = &CPU::EOR, .fetch = &CPU::IndirectY};

	instructions[0x09] = Instruction{.name = "ORA", .cycles = 2, .execute = &CPU::ORA, .fetch = &CPU::Immediate};
	instructions[0x05] = Instruction{.name = "ORA", .cycles = 3, .execute = &CPU::ORA, .fetch = &CPU::ZeroPage};
	instructions[0x15] = Instruction{.name = "ORA", .cycles = 4, .execute = &CPU::ORA, .fetch = &CPU::ZeroPageX};
	instructions[0x0D] = Instruction{.name = "ORA", .cycles = 4, .execute = &CPU::ORA, .fetch = &CPU::Absolute};
	instructions[0x1D] = Instruction{.name = "ORA", .cycles = 4, .execute = &CPU::ORA, .fetch = &CPU::AbsoluteX};
	instructions[0x19] = Instruction{.name = "ORA", .cycles = 4, .execute = &CPU::ORA, .fetch = &CPU::AbsoluteY};
	instructions[0x01] = Instruction{.name = "ORA", .cycles = 6, .execute = &CPU::ORA, .fetch = &CPU::IndirectX};
	instructions[0x11] = Instruction{.name = "ORA", .cycles = 5, .execute = &CPU::ORA, .fetch = &CPU::IndirectY};

	instructions[0x24] = Instruction{.name = "BIT", .cycles = 3, .execute = &CPU::BIT, .fetch = &CPU::ZeroPage};
	instructions[0x2C] = Instruction{.name = "BIT", .cycles = 4, .execute = &CPU::BIT, .fetch = &CPU::Absolute};

	instructions[0x69] = Instruction{.name = "ADC", .cycles = 2, .execute = &CPU::ADC, .fetch = &CPU::Immediate};
	instructions[0x65] = Instruction{.name = "ADC", .cycles = 3, .execute = &CPU::ADC, .fetch = &CPU::ZeroPage};
	instructions[0x75] = Instruction{.name = "ADC", .cycles = 4, .execute = &CPU::ADC, .fetch = &CPU::ZeroPageX};
	instructions[0x6D] = Instruction{.name = "ADC", .cycles = 4, .execute = &CPU::ADC, .fetch = &CPU::Absolute};
	instructions[0x7D] = Instruction{.name = "ADC", .cycles = 4, .execute = &CPU::ADC, .fetch = &CPU::AbsoluteX};
	instructions[0x79] = Instruction{.name = "ADC", .cycles = 4, .execute = &CPU::ADC, .fetch = &CPU::AbsoluteY};
	instructions[0x61] = Instruction{.name = "ADC", .cycles = 6, .execute = &CPU::ADC, .fetch = &CPU::IndirectX};
	instructions[0x71] = Instruction{.name = "ADC", .cycles = 5, .execute = &CPU::ADC, .fetch = &CPU::IndirectY};

	instructions[0xE9] = Instruction{.name = "SBC", .cycles = 2, .execute = &CPU::SBC, .fetch = &CPU::Immediate};
	instructions[0xE5] = Instruction{.name = "SBC", .cycles = 3, .execute = &CPU::SBC, .fetch = &CPU::ZeroPage};
	instructions[0xF5] = Instruction{.name = "SBC", .cycles = 4, .execute = &CPU::SBC, .fetch = &CPU::ZeroPageX};
	instructions[0xED] = Instruction{.name = "SBC", .cycles = 4, .execute = &CPU::SBC, .fetch = &CPU::Absolute};
	instructions[0xFD] = Instruction{.name = "SBC", .cycles = 4, .execute = &CPU::SBC, .fetch = &CPU::AbsoluteX};
	instructions[0xF9] = Instruction{.name = "SBC", .cycles = 4, .execute = &CPU::SBC, .fetch = &CPU::AbsoluteY};
	instructions[0xE1] = Instruction{.name = "SBC", .cycles = 6, .execute = &CPU::SBC, .fetch = &CPU::IndirectX};
	instructions[0xF1] = Instruction{.name = "SBC", .cycles = 5, .execute = &CPU::SBC, .fetch = &CPU::IndirectY};

	instructions[0xC9] = Instruction{.name = "CMP", .cycles = 2, .execute = &CPU::CMP, .fetch = &CPU::Immediate};
	instructions[0xC5] = Instruction{.name = "CMP", .cycles = 3, .execute = &CPU::CMP, .fetch = &CPU::ZeroPage};
	instructions[0xD5] = Instruction{.name = "CMP", .cycles = 4, .execute = &CPU::CMP, .fetch = &CPU::ZeroPageX};
	instructions[0xCD] = Instruction{.name = "CMP", .cycles = 4, .execute = &CPU::CMP, .fetch = &CPU::Absolute};
	instructions[0xDD] = Instruction{.name = "CMP", .cycles = 4, .execute = &CPU::CMP, .fetch = &CPU::AbsoluteX};
	instructions[0xD9] = Instruction{.name = "CMP", .cycles = 4, .execute = &CPU::CMP, .fetch = &CPU::AbsoluteY};
	instructions[0xC1] = Instruction{.name = "CMP", .cycles = 6, .execute = &CPU::CMP, .fetch = &CPU::IndirectX};
	instructions[0xD1] = Instruction{.name = "CMP", .cycles = 5, .execute = &CPU::CMP, .fetch = &CPU::IndirectY};

	instructions[0xE0] = Instruction{.name = "CPX", .cycles = 2, .execute = &CPU::CPX, .fetch = &CPU::Immediate};
	instructions[0xE4] = Instruction{.name = "CPX", .cycles = 3, .execute = &CPU::CPX, .fetch = &CPU::ZeroPage};
	instructions[0xEC] = Instruction{.name = "CPX", .cycles = 4, .execute = &CPU::CPX, .fetch = &CPU::Absolute};

	instructions[0xC0] = Instruction{.name = "CPY", .cycles = 2, .execute = &CPU::CPY, .fetch = &CPU::Immediate};
	instructions[0xC4] = Instruction{.name = "CPY", .cycles = 3, .execute = &CPU::CPY, .fetch = &CPU::ZeroPage};
	instructions[0xCC] = Instruction{.name = "CPY", .cycles = 4, .execute = &CPU::CPY, .fetch = &CPU::Absolute};

	instructions[0xE6] = Instruction{.name = "INC", .cycles = 5, .execute = &CPU::INC, .fetch = &CPU::ZeroPage};
	instructions[0xF6] = Instruction{.name = "INC", .cycles = 6, .execute = &CPU::INC, .fetch = &CPU::ZeroPageX};
	instructions[0xEE] = Instruction{.name = "INC", .cycles = 6, .execute = &CPU::INC, .fetch = &CPU::Absolute};
	instructions[0xFE] = Instruction{.name = "INC", .cycles = 7, .execute = &CPU::INC, .fetch = &CPU::AbsoluteX};

	instructions[0xE8] = Instruction{.name = "INX", .cycles = 2, .execute = &CPU::INX, .fetch = &CPU::Implicit};

	instructions[0xC8] = Instruction{.name = "INY", .cycles = 2, .execute = &CPU::INY, .fetch = &CPU::Implicit};

	instructions[0xC6] = Instruction{.name = "DEC", .cycles = 5, .execute = &CPU::DEC, .fetch = &CPU::ZeroPage};
	instructions[0xD6] = Instruction{.name = "DEC", .cycles = 6, .execute = &CPU::DEC, .fetch = &CPU::ZeroPageX};
	instructions[0xCE] = Instruction{.name = "DEC", .cycles = 6, .execute = &CPU::DEC, .fetch = &CPU::Absolute};
	instructions[0xDE] = Instruction{.name = "DEC", .cycles = 7, .execute = &CPU::DEC, .fetch = &CPU::AbsoluteX};

	instructions[0xCA] = Instruction{.name = "DEX", .cycles = 2, .execute = &CPU::DEX, .fetch = &CPU::Implicit};

	instructions[0x88] = Instruction{.name = "DEY", .cycles = 2, .execute = &CPU::DEY, .fetch = &CPU::Implicit};

	instructions[0x0A] = Instruction{.name = "ASL", .cycles = 2, .execute = &CPU::ASL, .fetch = &CPU::Implicit};
	instructions[0x06] = Instruction{.name = "ASL", .cycles = 5, .execute = &CPU::ASL, .fetch = &CPU::ZeroPage};
	instructions[0x16] = Instruction{.name = "ASL", .cycles = 6, .execute = &CPU::ASL, .fetch = &CPU::ZeroPageX};
	instructions[0x0E] = Instruction{.name = "ASL", .cycles = 6, .execute = &CPU::ASL, .fetch = &CPU::Absolute};
	instructions[0x1E] = Instruction{.name = "ASL", .cycles = 7, .execute = &CPU::ASL, .fetch = &CPU::AbsoluteX};

	instructions[0x4A] = Instruction{.name = "LSR", .cycles = 2, .execute = &CPU::LSR, .fetch = &CPU::Implicit};
	instructions[0x46] = Instruction{.name = "LSR", .cycles = 5, .execute = &CPU::LSR, .fetch = &CPU::ZeroPage};
	instructions[0x56] = Instruction{.name = "LSR", .cycles = 6, .execute = &CPU::LSR, .fetch = &CPU::ZeroPageX};
	instructions[0x4E] = Instruction{.name = "LSR", .cycles = 6, .execute = &CPU::LSR, .fetch = &CPU::Absolute};
	instructions[0x5E] = Instruction{.name = "LSR", .cycles = 7, .execute = &CPU::LSR, .fetch = &CPU::AbsoluteX};

	instructions[0x2A] = Instruction{.name = "ROL", .cycles = 2, .execute = &CPU::ROL, .fetch = &CPU::Implicit};
	instructions[0x26] = Instruction{.name = "ROL", .cycles = 5, .execute = &CPU::ROL, .fetch = &CPU::ZeroPage};
	instructions[0x36] = Instruction{.name = "ROL", .cycles = 6, .execute = &CPU::ROL, .fetch = &CPU::ZeroPageX};
	instructions[0x2E] = Instruction{.name = "ROL", .cycles = 6, .execute = &CPU::ROL, .fetch = &CPU::Absolute};
	instructions[0x3E] = Instruction{.name = "ROL", .cycles = 7, .execute = &CPU::ROL, .fetch = &CPU::AbsoluteX};

	instructions[0x6A] = Instruction{.name = "ROR", .cycles = 2, .execute = &CPU::ROR, .fetch = &CPU::Implicit};
	instructions[0x66] = Instruction{.name = "ROR", .cycles = 5, .execute = &CPU::ROR, .fetch = &CPU::ZeroPage};
	instructions[0x76] = Instruction{.name = "ROR", .cycles = 6, .execute = &CPU::ROR, .fetch = &CPU::ZeroPageX};
	instructions[0x6E] = Instruction{.name = "ROR", .cycles = 6, .execute = &CPU::ROR, .fetch = &CPU::Absolute};
	instructions[0x7E] = Instruction{.name = "ROR", .cycles = 7, .execute = &CPU::ROR, .fetch = &CPU::AbsoluteX};

	instructions[0x4C] = Instruction{.name = "JMP", .cycles = 3, .execute = &CPU::JMP, .fetch = &CPU::Absolute};
	instructions[0x6C] = Instruction{.name = "JMP", .cycles = 5, .execute = &CPU::JMP, .fetch = &CPU::Indirect};

	instructions[0x20] = Instruction{.name = "JSR", .cycles = 6, .execute = &CPU::JSR, .fetch = &CPU::Absolute};

	instructions[0x60] = Instruction{.name = "RTS", .cycles = 6, .execute = &CPU::RTS, .fetch = &CPU::Implicit};

	instructions[0x90] = Instruction{.name = "BCC", .cycles = 2, .execute = &CPU::BCC, .fetch = &CPU::Relative};
	instructions[0xB0] = Instruction{.name = "BCS", .cycles = 2, .execute = &CPU::BCS, .fetch = &CPU::Relative};
	instructions[0xF0] = Instruction{.name = "BEQ", .cycles = 2, .execute = &CPU::BEQ, .fetch = &CPU::Relative};
	instructions[0x30] = Instruction{.name = "BMI", .cycles = 2, .execute = &CPU::BMI, .fetch = &CPU::Relative};
	instructions[0xD0] = Instruction{.name = "BNE", .cycles = 2, .execute = &CPU::BNE, .fetch = &CPU::Relative};
	instructions[0x10] = Instruction{.name = "BPL", .cycles = 2, .execute = &CPU::BPL, .fetch = &CPU::Relative};
	instructions[0x50] = Instruction{.name = "BVC", .cycles = 2, .execute = &CPU::BVC, .fetch = &CPU::Relative};
	instructions[0x70] = Instruction{.name = "BVS", .cycles = 2, .execute = &CPU::BVS, .fetch = &CPU::Relative};

	instructions[0x18] = Instruction{.name = "CLC", .cycles = 2, .execute = &CPU::CLC, .fetch = &CPU::Implicit};
	instructions[0xD8] = Instruction{.name = "CLD", .cycles = 2, .execute = &CPU::CLD, .fetch = &CPU::Implicit};
	instructions[0x58] = Instruction{.name = "CLI", .cycles = 2, .execute = &CPU::CLI, .fetch = &CPU::Implicit};
	instructions[0xB8] = Instruction{.name = "CLV", .cycles = 2, .execute = &CPU::CLV, .fetch = &CPU::Implicit};
	instructions[0x38] = Instruction{.name = "SEC", .cycles = 2, .execute = &CPU::SEC, .fetch = &CPU::Implicit};
	instructions[0xF8] = Instruction{.name = "SED", .cycles = 2, .execute = &CPU::SED, .fetch = &CPU::Implicit};
	instructions[0x78] = Instruction{.name = "SEI", .cycles = 2, .execute = &CPU::SEI, .fetch = &CPU::Implicit};

	instructions[0x00] = Instruction{.name = "BRK", .cycles = 7, .execute = &CPU::BRK, .fetch = &CPU::Immediate};
	instructions[0xEA] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x40] = Instruction{.name = "RTI", .cycles = 6, .execute = &CPU::RTI, .fetch = &CPU::Implicit};

	instructions[0x1A] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x3A] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x5A] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x7A] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0xDA] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0xFA] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x80] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Immediate};
	instructions[0x82] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Immediate};
	instructions[0x89] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Immediate};
	instructions[0xC2] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Immediate};
	instructions[0xE2] = Instruction{.name = "NOP", .cycles = 2, .execute = &CPU::NOP, .fetch = &CPU::Immediate};
	instructions[0x04] = Instruction{.name = "NOP", .cycles = 3, .execute = &CPU::NOP, .fetch = &CPU::ZeroPage};
	instructions[0x44] = Instruction{.name = "NOP", .cycles = 3, .execute = &CPU::NOP, .fetch = &CPU::ZeroPage};
	instructions[0x64] = Instruction{.name = "NOP", .cycles = 3, .execute = &CPU::NOP, .fetch = &CPU::ZeroPage};
	instructions[0x14] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::ZeroPageX};
	instructions[0x34] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::ZeroPageX};
	instructions[0x54] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::ZeroPageX};
	instructions[0x74] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::ZeroPageX};
	instructions[0xD4] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::ZeroPageX};
	instructions[0xF4] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::ZeroPageX};
	instructions[0x0C] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::Absolute};
	instructions[0x1C] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::AbsoluteX};
	instructions[0x3C] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::AbsoluteX};
	instructions[0x5C] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::AbsoluteX};
	instructions[0x7C] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::AbsoluteX};
	instructions[0xDC] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::AbsoluteX};
	instructions[0xFC] = Instruction{.name = "NOP", .cycles = 4, .execute = &CPU::NOP, .fetch = &CPU::AbsoluteX};

	instructions[0x07] = Instruction{.name = "SLO", .cycles = 5, .execute = &CPU::SLO, .fetch = &CPU::ZeroPage};
	instructions[0x17] = Instruction{.name = "SLO", .cycles = 6, .execute = &CPU::SLO, .fetch = &CPU::ZeroPageX};
	instructions[0x0F] = Instruction{.name = "SLO", .cycles = 6, .execute = &CPU::SLO, .fetch = &CPU::Absolute};
	instructions[0x1F] = Instruction{.name = "SLO", .cycles = 7, .execute = &CPU::SLO, .fetch = &CPU::AbsoluteX};
	instructions[0x1B] = Instruction{.name = "SLO", .cycles = 7, .execute = &CPU::SLO, .fetch = &CPU::AbsoluteY};
	instructions[0x03] = Instruction{.name = "SLO", .cycles = 8, .execute = &CPU::SLO, .fetch = &CPU::IndirectX};
	instructions[0x13] = Instruction{.name = "SLO", .cycles = 8, .execute = &CPU::SLO, .fetch = &CPU::IndirectY};

	instructions[0x27] = Instruction{.name = "RLA", .cycles = 5, .execute = &CPU::RLA, .fetch = &CPU::ZeroPage};
	instructions[0x37] = Instruction{.name = "RLA", .cycles = 6, .execute = &CPU::RLA, .fetch = &CPU::ZeroPageX};
	instructions[0x2F] = Instruction{.name = "RLA", .cycles = 6, .execute = &CPU::RLA, .fetch = &CPU::Absolute};
	instructions[0x3F] = Instruction{.name = "RLA", .cycles = 7, .execute = &CPU::RLA, .fetch = &CPU::AbsoluteX};
	instructions[0x3B] = Instruction{.name = "RLA", .cycles = 7, .execute = &CPU::RLA, .fetch = &CPU::AbsoluteY};
	instructions[0x23] = Instruction{.name = "RLA", .cycles = 8, .execute = &CPU::RLA, .fetch = &CPU::IndirectX};
	instructions[0x33] = Instruction{.name = "RLA", .cycles = 8, .execute = &CPU::RLA, .fetch = &CPU::IndirectY};

	instructions[0x47] = Instruction{.name = "SRE", .cycles = 5, .execute = &CPU::SRE, .fetch = &CPU::ZeroPage};
	instructions[0x57] = Instruction{.name = "SRE", .cycles = 6, .execute = &CPU::SRE, .fetch = &CPU::ZeroPageX};
	instructions[0x4F] = Instruction{.name = "SRE", .cycles = 6, .execute = &CPU::SRE, .fetch = &CPU::Absolute};
	instructions[0x5F] = Instruction{.name = "SRE", .cycles = 7, .execute = &CPU::SRE, .fetch = &CPU::AbsoluteX};
	instructions[0x5B] = Instruction{.name = "SRE", .cycles = 7, .execute = &CPU::SRE, .fetch = &CPU::AbsoluteY};
	instructions[0x43] = Instruction{.name = "SRE", .cycles = 8, .execute = &CPU::SRE, .fetch = &CPU::IndirectX};
	instructions[0x53] = Instruction{.name = "SRE", .cycles = 8, .execute = &CPU::SRE, .fetch = &CPU::IndirectY};

	instructions[0x67] = Instruction{.name = "RRA", .cycles = 5, .execute = &CPU::RRA, .fetch = &CPU::ZeroPage};
	instructions[0x77] = Instruction{.name = "RRA", .cycles = 6, .execute = &CPU::RRA, .fetch = &CPU::ZeroPageX};
	instructions[0x6F] = Instruction{.name = "RRA", .cycles = 6, .execute = &CPU::RRA, .fetch = &CPU::Absolute};
	instructions[0x7F] = Instruction{.name = "RRA", .cycles = 7, .execute = &CPU::RRA, .fetch = &CPU::AbsoluteX};
	instructions[0x7B] = Instruction{.name = "RRA", .cycles = 7, .execute = &CPU::RRA, .fetch = &CPU::AbsoluteY};
	instructions[0x63] = Instruction{.name = "RRA", .cycles = 8, .execute = &CPU::RRA, .fetch = &CPU::IndirectX};
	instructions[0x73] = Instruction{.name = "RRA", .cycles = 8, .execute = &CPU::RRA, .fetch = &CPU::IndirectY};

	instructions[0x87] = Instruction{.name = "SAX", .cycles = 3, .execute = &CPU::SAX, .fetch = &CPU::ZeroPage};
	instructions[0x97] = Instruction{.name = "SAX", .cycles = 4, .execute = &CPU::SAX, .fetch = &CPU::ZeroPageY};
	instructions[0x8F] = Instruction{.name = "SAX", .cycles = 4, .execute = &CPU::SAX, .fetch = &CPU::Absolute};
	instructions[0x83] = Instruction{.name = "SAX", .cycles = 6, .execute = &CPU::SAX, .fetch = &CPU::IndirectX};

	instructions[0xEB] = Instruction{.name = "SBC", .cycles = 2, .execute = &CPU::SBC, .fetch = &CPU::Immediate};

	instructions[0xAB] = Instruction{.name = "LAX", .cycles = 2, .execute = &CPU::LAX, .fetch = &CPU::Immediate};
	instructions[0xA7] = Instruction{.name = "LAX", .cycles = 3, .execute = &CPU::LAX, .fetch = &CPU::ZeroPage};
	instructions[0xB7] = Instruction{.name = "LAX", .cycles = 4, .execute = &CPU::LAX, .fetch = &CPU::ZeroPageY};
	instructions[0xAF] = Instruction{.name = "LAX", .cycles = 4, .execute = &CPU::LAX, .fetch = &CPU::Absolute};
	instructions[0xBF] = Instruction{.name = "LAX", .cycles = 4, .execute = &CPU::LAX, .fetch = &CPU::AbsoluteY};
	instructions[0xA3] = Instruction{.name = "LAX", .cycles = 6, .execute = &CPU::LAX, .fetch = &CPU::IndirectX};
	instructions[0xB3] = Instruction{.name = "LAX", .cycles = 5, .execute = &CPU::LAX, .fetch = &CPU::IndirectY};

	instructions[0xC7] = Instruction{.name = "DCP", .cycles = 5, .execute = &CPU::DCP, .fetch = &CPU::ZeroPage};
	instructions[0xD7] = Instruction{.name = "DCP", .cycles = 6, .execute = &CPU::DCP, .fetch = &CPU::ZeroPageX};
	instructions[0xCF] = Instruction{.name = "DCP", .cycles = 6, .execute = &CPU::DCP, .fetch = &CPU::Absolute};
	instructions[0xDF] = Instruction{.name = "DCP", .cycles = 7, .execute = &CPU::DCP, .fetch = &CPU::AbsoluteX};
	instructions[0xDB] = Instruction{.name = "DCP", .cycles = 7, .execute = &CPU::DCP, .fetch = &CPU::AbsoluteY};
	instructions[0xC3] = Instruction{.name = "DCP", .cycles = 8, .execute = &CPU::DCP, .fetch = &CPU::IndirectX};
	instructions[0xD3] = Instruction{.name = "DCP", .cycles = 8, .execute = &CPU::DCP, .fetch = &CPU::IndirectY};

	instructions[0xE7] = Instruction{.name = "ISC", .cycles = 5, .execute = &CPU::ISC, .fetch = &CPU::ZeroPage};
	instructions[0xF7] = Instruction{.name = "ISC", .cycles = 6, .execute = &CPU::ISC, .fetch = &CPU::ZeroPageX};
	instructions[0xEF] = Instruction{.name = "ISC", .cycles = 6, .execute = &CPU::ISC, .fetch = &CPU::Absolute};
	instructions[0xFF] = Instruction{.name = "ISC", .cycles = 7, .execute = &CPU::ISC, .fetch = &CPU::AbsoluteX};
	instructions[0xFB] = Instruction{.name = "ISC", .cycles = 7, .execute = &CPU::ISC, .fetch = &CPU::AbsoluteY};
	instructions[0xE3] = Instruction{.name = "ISC", .cycles = 8, .execute = &CPU::ISC, .fetch = &CPU::IndirectX};
	instructions[0xF3] = Instruction{.name = "ISC", .cycles = 8, .execute = &CPU::ISC, .fetch = &CPU::IndirectY};

	instructions[0x0B] = Instruction{.name = "ANC", .cycles = 2, .execute = &CPU::ANC, .fetch = &CPU::Immediate};
	instructions[0x2B] = Instruction{.name = "ANC", .cycles = 2, .execute = &CPU::ANC, .fetch = &CPU::Immediate};
	instructions[0x4B] = Instruction{.name = "ALR", .cycles = 0, .execute = &CPU::ALR, .fetch = &CPU::Immediate};
	instructions[0x6B] = Instruction{.name = "ARR", .cycles = 0, .execute = &CPU::ARR, .fetch = &CPU::Immediate};
	instructions[0xCB] = Instruction{.name = "AXS", .cycles = 0, .execute = &CPU::AXS, .fetch = &CPU::Immediate};

	// Unused by NES
	instructions[0x9C] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x9E] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x8B] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x93] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x9B] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x9F] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0xBB] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x02] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x12] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x22] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x32] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x42] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x52] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x62] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x72] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0x92] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0xB2] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0xD2] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
	instructions[0xF2] = Instruction{.name = "ILL", .cycles = 0, .execute = &CPU::NOP, .fetch = &CPU::Implicit};
}

void CPU::Reset()
{
	uint8_t startAddressLsb = ReadMemory(RESET_VECTOR_LSB);
	uint8_t startAddressMsb = ReadMemory(RESET_VECTOR_MSB);
	uint16_t startAddress = ComposeAddress(startAddressMsb, startAddressLsb);

	pc = startAddress;
	cycles = 7u;
	status.SetByte(0x34u);
	sp = 0xFDu;
	memset(ram, 0, RAM_SIZE);
}

void CPU::StackPush(uint8_t val)
{
	// Pointing to free space; get address before decrement
	uint16_t address = STACK_START_ADDRESS | sp;
	--sp;

	WriteMemory(address, val);
}

uint8_t CPU::StackPop()
{
	// Pointing to free space; get address after increment
	++sp;
	uint16_t address = STACK_START_ADDRESS | sp;

	return ReadMemory(address);
}

uint64_t CPU::Cycle()
{
	if (nes->nmi)
	{
		NMI();
	}

	opcode = ReadMemory(pc);

	//Log();

	pageBoundaryCrossed = false;
	prevCycles = cycles;

	((*this).*(instructions[opcode].fetch))();

	((*this).*(instructions[opcode].execute))();

	cycles += instructions[opcode].cycles;

	return cycles - prevCycles;
}

void CPU::NMI()
{
	nes->nmi = false;

	uint8_t pcMsb = (pc & 0xFF00u) >> 8u;
	uint8_t pcLsb = pc & 0xFFu;

	StackPush(pcMsb);
	StackPush(pcLsb);

	Status statusCopy = status;
	statusCopy.b1 = 1u;
	statusCopy.b0 = 0u;

	StackPush(statusCopy.GetByte());

	pcMsb = ReadMemory(NMI_VECTOR_MSB);
	pcLsb = ReadMemory(NMI_VECTOR_LSB);

	pc = ComposeAddress(pcMsb, pcLsb);
}

void CPU::Log()
{
	Instruction& instruction = instructions[opcode];

	printf("%04X  ", pc);

	if (instruction.fetch == &CPU::Implicit)
	{
		printf("%02X        %s                             ", ReadMemory(pc), instruction.name);
	}
	else if (instruction.fetch == &CPU::Immediate)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand = ReadMemory(pc + 1);

		printf("%02X %02X     %s #$%02X                        ", op, operand, instruction.name, operand);
	}
	else if (instruction.fetch == &CPU::ZeroPage)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand = ReadMemory(pc + 1);
		printf("%02X %02X     %s $%02X                         ", op, operand, instruction.name, operand);
	}
	else if (instruction.fetch == &CPU::ZeroPageX)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand = ReadMemory(pc + 1);
		printf("%02X %02X     %s $%02X,X    ", op, operand, instruction.name, operand);
	}
	else if (instruction.fetch == &CPU::ZeroPageY)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand = ReadMemory(pc + 1);
		printf("%02X %02X     %s $%02X,Y    ", op, operand, instruction.name, operand);
	}
	else if (instruction.fetch == &CPU::IndirectX)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand = ReadMemory(pc + 1);
		printf("%02X %02X     %s ($%02X,X)                     ", op, operand, instruction.name, operand);
	}
	else if (instruction.fetch == &CPU::Relative)
	{
		uint8_t op = ReadMemory(pc);
		int8_t operand = ReadMemory(pc + 1);
		uint16_t address = pc + 2 + operand;
		printf("%02X %02X     %s $%04X                       ", op, (uint8_t)operand, instruction.name, address);
	}
	else if (instruction.fetch == &CPU::IndirectY)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand = ReadMemory(pc + 1);
		printf("%02X %02X     %s ($%02X),Y                     ", op, operand, instruction.name, operand);
	}
	else if (instruction.fetch == &CPU::Absolute)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand1 = ReadMemory(pc + 1);
		uint8_t operand2 = ReadMemory(pc + 2);
		printf("%02X %02X %02X  %s $%02X%02X                       ", op, operand1, operand2, instruction.name, operand2, operand1);
	}
	else if (instruction.fetch == &CPU::Indirect)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand1 = ReadMemory(pc + 1);
		uint8_t operand2 = ReadMemory(pc + 2);
		printf("%02X %02X %02X  %s ($%02X%02X)                     ", op, operand1, operand2, instruction.name, operand2, operand1);
	}
	else if (instruction.fetch == &CPU::AbsoluteX)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand1 = ReadMemory(pc + 1);
		uint8_t operand2 = ReadMemory(pc + 2);
		printf("%02X %02X %02X  %s $%02X%02X,X                     ", op, operand1, operand2, instruction.name, operand2, operand1);
	}
	else if (instruction.fetch == &CPU::AbsoluteY)
	{
		uint8_t op = ReadMemory(pc);
		uint8_t operand1 = ReadMemory(pc + 1);
		uint8_t operand2 = ReadMemory(pc + 2);
		printf("%02X %02X %02X  %s $%02X%02X,Y                     ", op, operand1, operand2, instruction.name, operand2, operand1);
	}

	printf("A:%02X X:%02X Y:%02X P:%02X SP:%02X CYC:%lu\n", acc, x, y, status.GetByte(), sp, cycles);
}

bool CPU::TestBits(uint8_t value, uint8_t bits)
{
	return (value & bits) == bits;
}

bool CPU::IsNegative(uint8_t value)
{
	// Bit 7 is set
	return TestBits(value, 1u << 7u);
}

bool CPU::IsPageBoundaryCrossed(uint16_t before, uint16_t after)
{
	// Any bits in upper byte indicates a page boundary crossing (pages are 0xFF)
	return (before & 0xFF00u) != (after & 0xFF00u);
}

uint16_t CPU::ComposeAddress(uint8_t msb, uint8_t lsb)
{
	return (msb << 8u) | lsb;
}

void CPU::WriteMemory(uint16_t address, uint8_t value)
{
	nes->Write(BusSource::CPU, address, value);
}

uint8_t CPU::ReadMemory(uint16_t address)
{
	return nes->Read(BusSource::CPU, address);
}