using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;

namespace MCEmuCore.GBMonolith
{
    public struct OpCode
    {
        public readonly byte Instruction;
        public byte? Arg1;
        public byte? Arg2;
    }
    class Cpu
    {
        private readonly CpuRegisters registers;
        #region OpCodes

        private readonly List<Func<OpCode, int>> OpCodeArray;
        #endregion

        public Cpu()
        {
            registers = new CpuRegisters();

            OpCodeArray = new List<Func<OpCode, int>>()
            {
                #region OpCodes
                #region OpCodes 0x00-0x0F
                // 0x00
                (op) => {
                    // NOP
                    registers.PC += 1;
                    return 4;
                },
                // 0x01
                (op) => {
                    // LD BC,d16
                    if (op.Arg1.HasValue && op.Arg2.HasValue)
                    {
                        registers.BC = (ushort)(op.Arg2 + (op.Arg1 << 8));
                        registers.PC += 3;
                        return 12;
                    }
                    else
                    {
                        throw new IllegalInstructionException(op, "Missing arguments for LD BC");
                    }
                },
                // 0x02
                (op) => {
                    // LD (BC), A
                    throw new NotImplementedException("LD (BC), A");
                },
                // 0x03
                (op) => {
                    registers.BC += 1;
                    registers.PC += 1;
                    return 8;
                },
                // 0x04
                (op) => {
                    // INC B
                    registers.B = IncrementRegister(registers.B);

                    return 4;
                },
                // 0x05
                (op) => {
                    // DEC B
                    registers.B = DecrementRegister(registers.B);

                    return 4;
                },
                // 0x06
                (op) => {
                    // LD B,d8
                    if (op.Arg1.HasValue)
                    {
                        registers.B = op.Arg1.Value;
                        registers.PC += 2;
                        return 8;
                    }
                    else
                    {
                        throw new IllegalInstructionException(op, "Missing arguments for LD B");
                    }
                },
                // 0x07
                (op) => {
                    // RLCA
                    registers.Flags.Zero = false;
                    registers.Flags.Subtract = false;
                    registers.Flags.HalfCarry = false;
                    registers.Flags.Carry = (registers.A & 0b1000_0000) != 0;

                    registers.A = (byte)((registers.A << 1) + (registers.A >> 7));
                    registers.PC += 1;
                    return 4;
                },
                // 0x08
                (op) => {
                    // LD (a16), SP
                    // Load SP into address
                    throw new NotImplementedException("LD (a16), SP");
                },
                // 0x09
                (op) => {
                    // ADD HL, BC
                    registers.HL = AddWideRegisters(registers.HL, registers.BC);

                    return 8;
                },
                // 0x0A
                (op) => {
                    // LD A, (BC)
                    // Load byte at address stored in BC into A
                    throw new NotImplementedException("LD A, (BC)");
                },
                // 0x0B
                (op) => {
                    // DEC BC
                    registers.BC -= 1;
                    registers.PC += 1;
                    return 8;
                },
                // 0x0C
                (op) => {
                    // INC C
                    registers.C = IncrementRegister(registers.C);

                    return 4;
                },
                // 0x0D
                (op) => {
                    // DEC C
                    registers.C = DecrementRegister(registers.C);

                    return 4;
                },
                // 0x0E
                (op) => {
                    // LD C,d8
                    if (op.Arg1.HasValue)
                    {
                        registers.C = op.Arg1.Value;
                        registers.PC += 2;
                        return 8;
                    }
                    else
                    {
                        throw new IllegalInstructionException(op, "Missing argument for LD B");
                    }
                },
                // 0x0F
                (op) => {
                    // RRCA
                    registers.Flags.Zero = false;
                    registers.Flags.Subtract = false;
                    registers.Flags.HalfCarry = false;
                    registers.Flags.Carry = (registers.A & 0b0000_0001) != 0;

                    registers.A = (byte)((registers.A >> 1) + (registers.A << 7));
                    registers.PC += 1;
                    return 4;
                },
                #endregion
                #region OpCodes 0x10-0x1F
                // 0x10
                (op) => {
                    // STOP 0
                    // Halts CPU & LCD until button pressed
                    throw new NotImplementedException("STOP");
                },
                // 0x11
                (op) => {
                    // LD DE, d16
                    if (op.Arg1.HasValue && op.Arg2.HasValue)
                    {
                        registers.DE = (ushort)(op.Arg2 + (op.Arg1 << 8));
                        registers.PC += 3;
                        return 12;
                    }
                    else
                    {
                        throw new IllegalInstructionException(op, "Missing arguments for LD DE");
                    }
                },
                // 0x12
                (op) => {
                    // LD (DE), A
                    throw new NotImplementedException("0x12");
                },
                // 0x13
                (op) => {
                    // INC DE
                    registers.DE += 1;
                    registers.PC += 1;
                    return 8;
                },
                // 0x14
                (op) => {
                    registers.D = IncrementRegister(registers.D);

                    return 4;
                },
                // 0x15
                (op) => {
                    registers.D = DecrementRegister(registers.D);

                    return 4;
                },
                // 0x16
                (op) => {
                    if (op.Arg1.HasValue)
                    {
                        registers.D = op.Arg1.Value;
                        registers.PC += 2;
                        return 8;
                    }
                    else
                    {
                        throw new IllegalInstructionException(op, "Missing arguments for LD D");
                    }
                },
                // 0x17
                (op) => {
                    // RLA
                    int carryBit = registers.Flags.Carry ? 1 : 0;

                    registers.Flags.Zero = false;
                    registers.Flags.Subtract = false;
                    registers.Flags.HalfCarry = false;
                    registers.Flags.Carry = (registers.A & 0b1000_0000) != 0;

                    registers.A = (byte)((registers.A << 1) + carryBit);
                    registers.PC += 1;
                    return 4;
                },
                // 0x18
                (op) => {
                    if (op.Arg1.HasValue)
                    {
                        byte relativeJump = op.Arg1.Value;
                        registers.PC += (ushort)(1 + relativeJump);
                        return 12;
                    }
                    else
                    {
                        throw new IllegalInstructionException(op, "Missing argument for JR r");
                    }
                },
                // 0x19
                (op) => {
                    // ADD HL, DE
                    registers.HL = AddWideRegisters(registers.HL, registers.DE);

                    return 8;
                },
                // 0x1A
                (op) => {
                    // LD A, (DE)
                    // Load byte at address stored in DE into A
                    throw new NotImplementedException("LD A, (DE)");
                },
                // 0x1B
                (op) => {
                    // DEC DE
                    registers.DE -= 1;
                    registers.PC += 1;

                    return 8;
                },
                // 0x1C
                (op) => {
                    registers.E = IncrementRegister(registers.E);

                    return 4;
                },
                // 0x1D
                (op) => {
                    registers.E = IncrementRegister(registers.E);

                    return 4;
                },
                // 0x1E
                (op) => {
                    if (op.Arg1.HasValue)
                    {
                        registers.E = op.Arg1.Value;
                        registers.PC += 2;
                        return 8;
                    }
                    else
                    {
                        throw new IllegalInstructionException(op, "Missing arguments for LD E");
                    }
                },
                // 0x1F
                (op) => {
                    // RRA
                    int carryBit = registers.Flags.Carry ? 1 : 0;

                    registers.Flags.Zero = false;
                    registers.Flags.Subtract = false;
                    registers.Flags.HalfCarry = false;
                    registers.Flags.Carry = (registers.A & 0b0000_0001) != 0;

                    registers.A = (byte)((registers.A >> 1) + (carryBit << 7));
                    registers.PC += 1;
                    return 4;
                },
                #endregion
                #region OpCodes 0x20-0x2F
                // 0x20
                (op) => {
                    throw new NotImplementedException("0x20");
                },
                // 0x21
                (op) => {
                    throw new NotImplementedException("0x21");
                },
                // 0x22
                (op) => {
                    throw new NotImplementedException("0x22");
                },
                // 0x23
                (op) => {
                    throw new NotImplementedException("0x23");
                },
                // 0x24
                (op) => {
                    throw new NotImplementedException("0x24");
                },
                // 0x25
                (op) => {
                    throw new NotImplementedException("0x25");
                },
                // 0x26
                (op) => {
                    throw new NotImplementedException("0x26");
                },
                // 0x27
                (op) => {
                    throw new NotImplementedException("0x27");
                },
                // 0x28
                (op) => {
                    throw new NotImplementedException("0x28");
                },
                // 0x29
                (op) => {
                    throw new NotImplementedException("0x29");
                },
                // 0x2A
                (op) => {
                    throw new NotImplementedException("0x2A");
                },
                // 0x2B
                (op) => {
                    throw new NotImplementedException("0x2B");
                },
                // 0x2C
                (op) => {
                    throw new NotImplementedException("0x2C");
                },
                // 0x2D
                (op) => {
                    throw new NotImplementedException("0x2D");
                },
                // 0x2E
                (op) => {
                    throw new NotImplementedException("0x2E");
                },
                // 0x2F
                (op) => {
                    throw new NotImplementedException("0x2F");
                },
                #endregion
                #region OpCodes 0x30-0x3F
                // 0x30
                (op) => {
                    throw new NotImplementedException("0x30");
                },
                // 0x31
                (op) => {
                    throw new NotImplementedException("0x31");
                },
                // 0x32
                (op) => {
                    throw new NotImplementedException("0x32");
                },
                // 0x33
                (op) => {
                    throw new NotImplementedException("0x33");
                },
                // 0x34
                (op) => {
                    throw new NotImplementedException("0x34");
                },
                // 0x35
                (op) => {
                    throw new NotImplementedException("0x35");
                },
                // 0x36
                (op) => {
                    throw new NotImplementedException("0x36");
                },
                // 0x37
                (op) => {
                    throw new NotImplementedException("0x37");
                },
                // 0x38
                (op) => {
                    throw new NotImplementedException("0x38");
                },
                // 0x39
                (op) => {
                    throw new NotImplementedException("0x39");
                },
                // 0x3A
                (op) => {
                    throw new NotImplementedException("0x3A");
                },
                // 0x3B
                (op) => {
                    throw new NotImplementedException("0x3B");
                },
                // 0x3C
                (op) => {
                    throw new NotImplementedException("0x3C");
                },
                // 0x3D
                (op) => {
                    throw new NotImplementedException("0x3D");
                },
                // 0x3E
                (op) => {
                    throw new NotImplementedException("0x3E");
                },
                // 0x3F
                (op) => {
                    throw new NotImplementedException("0x3F");
                },
                #endregion
                #region OpCodes 0x40-0x4F
                // 0x40
                (op) => {
                    throw new NotImplementedException("0x40");
                },
                // 0x41
                (op) => {
                    throw new NotImplementedException("0x41");
                },
                // 0x42
                (op) => {
                    throw new NotImplementedException("0x42");
                },
                // 0x43
                (op) => {
                    throw new NotImplementedException("0x43");
                },
                // 0x44
                (op) => {
                    throw new NotImplementedException("0x44");
                },
                // 0x45
                (op) => {
                    throw new NotImplementedException("0x45");
                },
                // 0x46
                (op) => {
                    throw new NotImplementedException("0x46");
                },
                // 0x47
                (op) => {
                    throw new NotImplementedException("0x47");
                },
                // 0x48
                (op) => {
                    throw new NotImplementedException("0x48");
                },
                // 0x49
                (op) => {
                    throw new NotImplementedException("0x49");
                },
                // 0x4A
                (op) => {
                    throw new NotImplementedException("0x4A");
                },
                // 0x4B
                (op) => {
                    throw new NotImplementedException("0x4B");
                },
                // 0x4C
                (op) => {
                    throw new NotImplementedException("0x4C");
                },
                // 0x4D
                (op) => {
                    throw new NotImplementedException("0x4D");
                },
                // 0x4E
                (op) => {
                    throw new NotImplementedException("0x4E");
                },
                // 0x4F
                (op) => {
                    throw new NotImplementedException("0x4F");
                },
                #endregion
                #region OpCodes 0x50-0x5F
                // 0x50
                (op) => {
                    throw new NotImplementedException("0x50");
                },
                // 0x51
                (op) => {
                    throw new NotImplementedException("0x51");
                },
                // 0x52
                (op) => {
                    throw new NotImplementedException("0x52");
                },
                // 0x53
                (op) => {
                    throw new NotImplementedException("0x53");
                },
                // 0x54
                (op) => {
                    throw new NotImplementedException("0x54");
                },
                // 0x55
                (op) => {
                    throw new NotImplementedException("0x55");
                },
                // 0x56
                (op) => {
                    throw new NotImplementedException("0x56");
                },
                // 0x57
                (op) => {
                    throw new NotImplementedException("0x57");
                },
                // 0x58
                (op) => {
                    throw new NotImplementedException("0x58");
                },
                // 0x59
                (op) => {
                    throw new NotImplementedException("0x59");
                },
                // 0x5A
                (op) => {
                    throw new NotImplementedException("0x5A");
                },
                // 0x5B
                (op) => {
                    throw new NotImplementedException("0x5B");
                },
                // 0x5C
                (op) => {
                    throw new NotImplementedException("0x5C");
                },
                // 0x5D
                (op) => {
                    throw new NotImplementedException("0x5D");
                },
                // 0x5E
                (op) => {
                    throw new NotImplementedException("0x5E");
                },
                // 0x5F
                (op) => {
                    throw new NotImplementedException("0x5F");
                },
                #endregion
                #region OpCodes 0x60-0x6F
                // 0x60
                (op) => {
                    throw new NotImplementedException("0x60");
                },
                // 0x61
                (op) => {
                    throw new NotImplementedException("0x61");
                },
                // 0x62
                (op) => {
                    throw new NotImplementedException("0x62");
                },
                // 0x63
                (op) => {
                    throw new NotImplementedException("0x63");
                },
                // 0x64
                (op) => {
                    throw new NotImplementedException("0x64");
                },
                // 0x65
                (op) => {
                    throw new NotImplementedException("0x65");
                },
                // 0x66
                (op) => {
                    throw new NotImplementedException("0x66");
                },
                // 0x67
                (op) => {
                    throw new NotImplementedException("0x67");
                },
                // 0x68
                (op) => {
                    throw new NotImplementedException("0x68");
                },
                // 0x69
                (op) => {
                    throw new NotImplementedException("0x69");
                },
                // 0x6A
                (op) => {
                    throw new NotImplementedException("0x6A");
                },
                // 0x6B
                (op) => {
                    throw new NotImplementedException("0x6B");
                },
                // 0x6C
                (op) => {
                    throw new NotImplementedException("0x6C");
                },
                // 0x6D
                (op) => {
                    throw new NotImplementedException("0x6D");
                },
                // 0x6E
                (op) => {
                    throw new NotImplementedException("0x6E");
                },
                // 0x6F
                (op) => {
                    throw new NotImplementedException("0x6F");
                },
                #endregion
                #region OpCodes 0x70-0x7F
                // 0x70
                (op) => {
                    throw new NotImplementedException("0x70");
                },
                // 0x71
                (op) => {
                    throw new NotImplementedException("0x71");
                },
                // 0x72
                (op) => {
                    throw new NotImplementedException("0x72");
                },
                // 0x73
                (op) => {
                    throw new NotImplementedException("0x73");
                },
                // 0x74
                (op) => {
                    throw new NotImplementedException("0x74");
                },
                // 0x75
                (op) => {
                    throw new NotImplementedException("0x75");
                },
                // 0x76
                (op) => {
                    throw new NotImplementedException("0x76");
                },
                // 0x77
                (op) => {
                    throw new NotImplementedException("0x77");
                },
                // 0x78
                (op) => {
                    throw new NotImplementedException("0x78");
                },
                // 0x79
                (op) => {
                    throw new NotImplementedException("0x79");
                },
                // 0x7A
                (op) => {
                    throw new NotImplementedException("0x7A");
                },
                // 0x7B
                (op) => {
                    throw new NotImplementedException("0x7B");
                },
                // 0x7C
                (op) => {
                    throw new NotImplementedException("0x7C");
                },
                // 0x7D
                (op) => {
                    throw new NotImplementedException("0x7D");
                },
                // 0x7E
                (op) => {
                    throw new NotImplementedException("0x7E");
                },
                // 0x7F
                (op) => {
                    throw new NotImplementedException("0x7F");
                },
                #endregion
                #region OpCodes 0x80-0x8F
                // 0x80
                (op) => {
                    throw new NotImplementedException("0x80");
                },
                // 0x81
                (op) => {
                    throw new NotImplementedException("0x81");
                },
                // 0x82
                (op) => {
                    throw new NotImplementedException("0x82");
                },
                // 0x83
                (op) => {
                    throw new NotImplementedException("0x83");
                },
                // 0x84
                (op) => {
                    throw new NotImplementedException("0x84");
                },
                // 0x85
                (op) => {
                    throw new NotImplementedException("0x85");
                },
                // 0x86
                (op) => {
                    throw new NotImplementedException("0x86");
                },
                // 0x87
                (op) => {
                    throw new NotImplementedException("0x87");
                },
                // 0x88
                (op) => {
                    throw new NotImplementedException("0x88");
                },
                // 0x89
                (op) => {
                    throw new NotImplementedException("0x89");
                },
                // 0x8A
                (op) => {
                    throw new NotImplementedException("0x8A");
                },
                // 0x8B
                (op) => {
                    throw new NotImplementedException("0x8B");
                },
                // 0x8C
                (op) => {
                    throw new NotImplementedException("0x8C");
                },
                // 0x8D
                (op) => {
                    throw new NotImplementedException("0x8D");
                },
                // 0x8E
                (op) => {
                    throw new NotImplementedException("0x8E");
                },
                // 0x8F
                (op) => {
                    throw new NotImplementedException("0x8F");
                },
                #endregion
                #region OpCodes 0x90-0x9F
                // 0x90
                (op) => {
                    throw new NotImplementedException("0x90");
                },
                // 0x91
                (op) => {
                    throw new NotImplementedException("0x91");
                },
                // 0x92
                (op) => {
                    throw new NotImplementedException("0x92");
                },
                // 0x93
                (op) => {
                    throw new NotImplementedException("0x93");
                },
                // 0x94
                (op) => {
                    throw new NotImplementedException("0x94");
                },
                // 0x95
                (op) => {
                    throw new NotImplementedException("0x95");
                },
                // 0x96
                (op) => {
                    throw new NotImplementedException("0x96");
                },
                // 0x97
                (op) => {
                    throw new NotImplementedException("0x97");
                },
                // 0x98
                (op) => {
                    throw new NotImplementedException("0x98");
                },
                // 0x99
                (op) => {
                    throw new NotImplementedException("0x99");
                },
                // 0x9A
                (op) => {
                    throw new NotImplementedException("0x9A");
                },
                // 0x9B
                (op) => {
                    throw new NotImplementedException("0x9B");
                },
                // 0x9C
                (op) => {
                    throw new NotImplementedException("0x9C");
                },
                // 0x9D
                (op) => {
                    throw new NotImplementedException("0x9D");
                },
                // 0x9E
                (op) => {
                    throw new NotImplementedException("0x9E");
                },
                // 0x9F
                (op) => {
                    throw new NotImplementedException("0x9F");
                },
                #endregion
                #region OpCodes 0xA0-0xAF
                // 0xA0
                (op) => {
                    throw new NotImplementedException("0xA0");
                },
                // 0xA1
                (op) => {
                    throw new NotImplementedException("0xA1");
                },
                // 0xA2
                (op) => {
                    throw new NotImplementedException("0xA2");
                },
                // 0xA3
                (op) => {
                    throw new NotImplementedException("0xA3");
                },
                // 0xA4
                (op) => {
                    throw new NotImplementedException("0xA4");
                },
                // 0xA5
                (op) => {
                    throw new NotImplementedException("0xA5");
                },
                // 0xA6
                (op) => {
                    throw new NotImplementedException("0xA6");
                },
                // 0xA7
                (op) => {
                    throw new NotImplementedException("0xA7");
                },
                // 0xA8
                (op) => {
                    throw new NotImplementedException("0xA8");
                },
                // 0xA9
                (op) => {
                    throw new NotImplementedException("0xA9");
                },
                // 0xAA
                (op) => {
                    throw new NotImplementedException("0xAA");
                },
                // 0xAB
                (op) => {
                    throw new NotImplementedException("0xAB");
                },
                // 0xAC
                (op) => {
                    throw new NotImplementedException("0xAC");
                },
                // 0xAD
                (op) => {
                    throw new NotImplementedException("0xAD");
                },
                // 0xAE
                (op) => {
                    throw new NotImplementedException("0xAE");
                },
                // 0xAF
                (op) => {
                    throw new NotImplementedException("0xAF");
                },
                #endregion
                #region OpCodes 0xB0-0xBF
                // 0xB0
                (op) => {
                    throw new NotImplementedException("0xB0");
                },
                // 0xB1
                (op) => {
                    throw new NotImplementedException("0xB1");
                },
                // 0xB2
                (op) => {
                    throw new NotImplementedException("0xB2");
                },
                // 0xB3
                (op) => {
                    throw new NotImplementedException("0xB3");
                },
                // 0xB4
                (op) => {
                    throw new NotImplementedException("0xB4");
                },
                // 0xB5
                (op) => {
                    throw new NotImplementedException("0xB5");
                },
                // 0xB6
                (op) => {
                    throw new NotImplementedException("0xB6");
                },
                // 0xB7
                (op) => {
                    throw new NotImplementedException("0xB7");
                },
                // 0xB8
                (op) => {
                    throw new NotImplementedException("0xB8");
                },
                // 0xB9
                (op) => {
                    throw new NotImplementedException("0xB9");
                },
                // 0xBA
                (op) => {
                    throw new NotImplementedException("0xBA");
                },
                // 0xBB
                (op) => {
                    throw new NotImplementedException("0xBB");
                },
                // 0xBC
                (op) => {
                    throw new NotImplementedException("0xBC");
                },
                // 0xBD
                (op) => {
                    throw new NotImplementedException("0xBD");
                },
                // 0xBE
                (op) => {
                    throw new NotImplementedException("0xBE");
                },
                // 0xBF
                (op) => {
                    throw new NotImplementedException("0xBF");
                },
                #endregion
                #region OpCodes 0xC0-0xCF
                // 0xC0
                (op) => {
                    throw new NotImplementedException("0xC0");
                },
                // 0xC1
                (op) => {
                    throw new NotImplementedException("0xC1");
                },
                // 0xC2
                (op) => {
                    throw new NotImplementedException("0xC2");
                },
                // 0xC3
                (op) => {
                    throw new NotImplementedException("0xC3");
                },
                // 0xC4
                (op) => {
                    throw new NotImplementedException("0xC4");
                },
                // 0xC5
                (op) => {
                    throw new NotImplementedException("0xC5");
                },
                // 0xC6
                (op) => {
                    throw new NotImplementedException("0xC6");
                },
                // 0xC7
                (op) => {
                    throw new NotImplementedException("0xC7");
                },
                // 0xC8
                (op) => {
                    throw new NotImplementedException("0xC8");
                },
                // 0xC9
                (op) => {
                    throw new NotImplementedException("0xC9");
                },
                // 0xCA
                (op) => {
                    throw new NotImplementedException("0xCA");
                },
                // 0xCB
                (op) => {
                    throw new NotImplementedException("0xCB");
                },
                // 0xCC
                (op) => {
                    throw new NotImplementedException("0xCC");
                },
                // 0xCD
                (op) => {
                    throw new NotImplementedException("0xCD");
                },
                // 0xCE
                (op) => {
                    throw new NotImplementedException("0xCE");
                },
                // 0xCF
                (op) => {
                    throw new NotImplementedException("0xCF");
                },
                #endregion
                #region OpCodes 0xD0-0xDF
                // 0xD0
                (op) => {
                    throw new NotImplementedException("0xD0");
                },
                // 0xD1
                (op) => {
                    throw new NotImplementedException("0xD1");
                },
                // 0xD2
                (op) => {
                    throw new NotImplementedException("0xD2");
                },
                // 0xD3
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xD4
                (op) => {
                    throw new NotImplementedException("0xD4");
                },
                // 0xD5
                (op) => {
                    throw new NotImplementedException("0xD5");
                },
                // 0xD6
                (op) => {
                    throw new NotImplementedException("0xD6");
                },
                // 0xD7
                (op) => {
                    throw new NotImplementedException("0xD7");
                },
                // 0xD8
                (op) => {
                    throw new NotImplementedException("0xD8");
                },
                // 0xD9
                (op) => {
                    throw new NotImplementedException("0xD9");
                },
                // 0xDA
                (op) => {
                    throw new NotImplementedException("0xDA");
                },
                // 0xDB
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xDC
                (op) => {
                    throw new NotImplementedException("0xDC");
                },
                // 0xDD
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xDE
                (op) => {
                    throw new NotImplementedException("0xDE");
                },
                // 0xDF
                (op) => {
                    throw new NotImplementedException("0xDF");
                },
                #endregion
                #region OpCodes 0xE0-0xEF
                // 0xE0
                (op) => {
                    throw new NotImplementedException("0xE0");
                },
                // 0xE1
                (op) => {
                    throw new NotImplementedException("0xE1");
                },
                // 0xE2
                (op) => {
                    throw new NotImplementedException("0xE2");
                },
                // 0xE3
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xE4
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xE5
                (op) => {
                    throw new NotImplementedException("0xE5");
                },
                // 0xE6
                (op) => {
                    throw new NotImplementedException("0xE6");
                },
                // 0xE7
                (op) => {
                    throw new NotImplementedException("0xE7");
                },
                // 0xE8
                (op) => {
                    throw new NotImplementedException("0xE8");
                },
                // 0xE9
                (op) => {
                    throw new NotImplementedException("0xE9");
                },
                // 0xEA
                (op) => {
                    throw new NotImplementedException("0xEA");
                },
                // 0xEB
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xEC
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xED
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xEE
                (op) => {
                    throw new NotImplementedException("0xEE");
                },
                // 0xEF
                (op) => {
                    throw new NotImplementedException("0xEF");
                },
                #endregion
                #region OpCodes 0xF0-0xFF
                // 0xF0
                (op) => {
                    throw new NotImplementedException("0xF0");
                },
                // 0xF1
                (op) => {
                    throw new NotImplementedException("0xF1");
                },
                // 0xF2
                (op) => {
                    throw new NotImplementedException("0xF2");
                },
                // 0xF3
                (op) => {
                    throw new NotImplementedException("0xF3");
                },
                // 0xF4
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xF5
                (op) => {
                    throw new NotImplementedException("0xF5");
                },
                // 0xF6
                (op) => {
                    throw new NotImplementedException("0xF6");
                },
                // 0xF7
                (op) => {
                    throw new NotImplementedException("0xF7");
                },
                // 0xF8
                (op) => {
                    throw new NotImplementedException("0xF8");
                },
                // 0xF9
                (op) => {
                    throw new NotImplementedException("0xF9");
                },
                // 0xFA
                (op) => {
                    throw new NotImplementedException("0xFA");
                },
                // 0xFB
                (op) => {
                    throw new NotImplementedException("0xFB");
                },
                // 0xFC
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xFD
                (op) => {
                    throw new IllegalInstructionException(op, "Instruction does not exist");
                },
                // 0xFE
                (op) => {
                    throw new NotImplementedException("0xFE");
                },
                // 0xFF
                (op) => {
                    throw new NotImplementedException("0xFF");
                }
                #endregion
                #endregion
            };
        }

        private byte IncrementRegister(byte register)
        {
            byte reg = (byte)(register + 1);

            registers.Flags.Subtract = false;
            registers.Flags.Zero = reg == 0;
            // This logic only works for the increment operation
            registers.Flags.HalfCarry = reg == 16;

            registers.PC += 1;
            return reg;
        }

        private byte DecrementRegister(byte register)
        {
            byte reg = (byte)((uint)register - 1);

            registers.Flags.Subtract = true;
            registers.Flags.Zero = reg == 0;
            // This logic only works for the decrement operation
            registers.Flags.HalfCarry = reg == 15;

            registers.PC += 1;
            return reg;
        }

        private ushort AddWideRegisters(ushort wideRegister1, ushort wideRegister2)
        {
            // ADD HL, BC
            registers.Flags.Subtract = false;
            registers.Flags.HalfCarry = (((wideRegister1 & 0x0FFF) + (wideRegister2 & 0x0FFF) & 0x1000) == 0x1000);
            registers.Flags.Carry = (((wideRegister1 + wideRegister2) & 0x10000) == 0x10000);

            registers.PC += 1;

            return (ushort)(wideRegister1 + wideRegister2);
        }
    }


    [Serializable]
    public class IllegalInstructionException : Exception
    {
        public OpCode OpCode { get; set; }
        public IllegalInstructionException() { }
        public IllegalInstructionException(OpCode opCode, string message) : base(message)
        {
            OpCode = opCode;
        }
        public IllegalInstructionException(string message) : base(message) { }
        public IllegalInstructionException(string message, Exception inner) : base(message, inner) { }
        protected IllegalInstructionException(
          System.Runtime.Serialization.SerializationInfo info,
          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
    }
}