//
// Copyright (c) Adrian Conlon. All rights reserved.
//
namespace EightBit
{
using System;
public class Z80 : IntelProcessor
{
private readonly InputOutput ports;
private readonly Register16[] accumulatorFlags = { new Register16(), new Register16() };
private readonly Register16[,] registers =
{
{
new Register16(), new Register16(), new Register16(),
},
{
new Register16(), new Register16(), new Register16(),
},
};
private readonly Register16 intermediate = new Register16();
private RefreshRegister refresh = new RefreshRegister(0x7f);
private bool prefixCB = false;
private bool prefixDD = false;
private bool prefixED = false;
private PinLevel nmiLine = PinLevel.Low;
private PinLevel m1Line = PinLevel.Low;
private PinLevel iorqLine = PinLevel.Low;
private PinLevel rdLine = PinLevel.Low;
private PinLevel wrLine = PinLevel.Low;
private int accumulatorFlagsSet = 0;
private int registerSet = 0;
private sbyte displacement = 0;
private bool displaced = false;
public Z80(Bus bus, InputOutput ports)
: base(bus) => this.ports = ports;
public event EventHandler ExecutingInstruction;
public event EventHandler ExecutedInstruction;
public event EventHandler RaisingNMI;
public event EventHandler RaisedNMI;
public event EventHandler LoweringNMI;
public event EventHandler LoweredNMI;
public event EventHandler RaisingM1;
public event EventHandler RaisedM1;
public event EventHandler LoweringM1;
public event EventHandler LoweredM1;
public event EventHandler RaisingIORQ;
public event EventHandler RaisedIORQ;
public event EventHandler LoweringIORQ;
public event EventHandler LoweredIORQ;
public event EventHandler RaisingRD;
public event EventHandler RaisedRD;
public event EventHandler LoweringRD;
public event EventHandler LoweredRD;
public event EventHandler RaisingWR;
public event EventHandler RaisedWR;
public event EventHandler LoweringWR;
public event EventHandler LoweredWR;
public byte IV { get; set; } = 0xff;
public int IM { get; set; } = 0;
public bool IFF1 { get; set; } = false;
public bool IFF2 { get; set; } = false;
public override Register16 AF => this.accumulatorFlags[this.accumulatorFlagsSet];
public override Register16 BC => this.registers[this.registerSet, (int)RegisterIndex.IndexBC];
public override Register16 DE => this.registers[this.registerSet, (int)RegisterIndex.IndexDE];
public override Register16 HL => this.registers[this.registerSet, (int)RegisterIndex.IndexHL];
public Register16 IX { get; } = new Register16(0xffff);
public byte IXH { get => this.IX.High; set => this.IX.High = value; }
public byte IXL { get => this.IX.Low; set => this.IX.Low = value; }
public Register16 IY { get; } = new Register16(0xffff);
public byte IYH { get => this.IY.High; set => this.IY.High = value; }
public byte IYL { get => this.IY.Low; set => this.IY.Low = value; }
public ref RefreshRegister REFRESH => ref this.refresh;
public ref PinLevel NMI => ref this.nmiLine;
public ref PinLevel M1 => ref this.m1Line;
public ref PinLevel IORQ => ref this.iorqLine;
public ref PinLevel RD => ref this.rdLine;
public ref PinLevel WR => ref this.wrLine;
private ushort DisplacedAddress
{
get
{
var returned = (this.prefixDD ? this.IX : this.IY).Word + this.displacement;
return this.MEMPTR.Word = (ushort)returned;
}
}
public void Exx() => this.registerSet ^= 1;
public void ExxAF() => this.accumulatorFlagsSet ^= 1;
public virtual void RaiseNMI()
{
if (this.NMI.Lowered())
{
this.OnRaisingNMI();
this.NMI.Raise();
this.OnRaisedNMI();
}
}
public virtual void LowerNMI()
{
if (this.NMI.Raised())
{
this.OnLoweringNMI();
this.NMI.Lower();
this.OnLoweredNMI();
}
}
public virtual void RaiseM1()
{
if (this.M1.Lowered())
{
this.OnRaisingM1();
this.M1.Raise();
this.OnRaisedM1();
}
}
public virtual void LowerM1()
{
if (this.M1.Raised())
{
this.OnLoweringM1();
this.M1.Lower();
this.OnLoweredM1();
}
}
public virtual void RaiseIORQ()
{
if (this.IORQ.Lowered())
{
this.OnRaisingIORQ();
this.IORQ.Raise();
this.OnRaisedIORQ();
}
}
public virtual void LowerIORQ()
{
if (this.IORQ.Raised())
{
this.OnLoweringIORQ();
this.IORQ.Lower();
this.OnLoweredIORQ();
}
}
public virtual void RaiseRD()
{
if (this.RD.Lowered())
{
this.OnRaisingRD();
this.RD.Raise();
this.OnRaisedRD();
}
}
public virtual void LowerRD()
{
if (this.RD.Raised())
{
this.OnLoweringRD();
this.RD.Lower();
this.OnLoweredRD();
}
}
public virtual void RaiseWR()
{
if (this.WR.Lowered())
{
this.OnRaisingWR();
this.WR.Raise();
this.OnRaisedWR();
}
}
public virtual void LowerWR()
{
if (this.WR.Raised())
{
this.OnLoweringWR();
this.WR.Lower();
this.OnLoweredWR();
}
}
public override int Execute()
{
this.RaiseM1();
var decoded = this.GetDecodedOpCode(this.OpCode);
var x = decoded.X;
var y = decoded.Y;
var z = decoded.Z;
var p = decoded.P;
var q = decoded.Q;
if (this.prefixCB)
{
this.ExecuteCB(x, y, z);
}
else if (this.prefixED)
{
this.ExecuteED(x, y, z, p, q);
}
else
{
this.ExecuteOther(x, y, z, p, q);
}
return this.Cycles;
}
public override int Step()
{
this.ResetCycles();
this.OnExecutingInstruction();
if (this.Powered)
{
this.displaced = this.prefixCB = this.prefixDD = this.prefixED = false;
var handled = false;
if (this.RESET.Lowered())
{
this.HandleRESET();
handled = true;
}
else if (this.NMI.Lowered())
{
this.HandleNMI();
handled = true;
}
else if (this.INT.Lowered())
{
this.RaiseHALT();
if (handled = this.IFF1)
{
this.HandleINT();
}
}
else if (this.HALT.Lowered())
{
this.Execute(0); // NOP
}
if (!handled)
{
this.LowerM1();
this.Execute(this.FetchByte());
}
}
this.OnExecutedInstruction();
return this.Cycles;
}
protected override void OnRaisedPOWER()
{
this.RaiseM1();
this.RaiseIORQ();
this.RaiseRD();
this.RaiseWR();
this.DisableInterrupts();
this.IM = 0;
this.REFRESH = new RefreshRegister(0);
this.IV = (byte)Mask.Mask8;
this.AF.Word = this.IX.Word = this.IY.Word = this.BC.Word = this.DE.Word = this.HL.Word = (ushort)Mask.Mask16;
this.ExxAF();
this.Exx();
this.prefixCB = this.prefixDD = this.prefixED = false;
base.OnRaisedPOWER();
}
protected virtual void OnExecutingInstruction() => this.ExecutingInstruction?.Invoke(this, EventArgs.Empty);
protected virtual void OnExecutedInstruction() => this.ExecutedInstruction?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisingNMI() => this.RaisingNMI?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisedNMI() => this.RaisedNMI?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweringNMI() => this.LoweringNMI?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweredNMI() => this.LoweredNMI?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisingM1() => this.RaisingM1?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisedM1() => this.RaisedM1?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweringM1() => this.LoweringM1?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweredM1()
{
++this.REFRESH;
this.LoweredM1?.Invoke(this, EventArgs.Empty);
}
protected virtual void OnLoweringIORQ() => this.LoweringIORQ?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweredIORQ() => this.LoweredIORQ?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisingIORQ() => this.RaisingIORQ?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisedIORQ() => this.RaisedIORQ?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweringRD() => this.LoweringRD?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweredRD() => this.LoweredRD?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisingRD() => this.RaisingRD?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisedRD() => this.RaisedRD?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweringWR() => this.LoweringWR?.Invoke(this, EventArgs.Empty);
protected virtual void OnLoweredWR() => this.LoweredWR?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisingWR() => this.RaisingWR?.Invoke(this, EventArgs.Empty);
protected virtual void OnRaisedWR() => this.RaisedWR?.Invoke(this, EventArgs.Empty);
protected override void BusWrite()
{
this.LowerWR();
base.BusWrite();
this.RaiseWR();
}
protected override byte BusRead()
{
this.LowerRD();
var returned = base.BusRead();
this.RaiseRD();
return returned;
}
protected override void HandleRESET()
{
base.HandleRESET();
this.DisableInterrupts();
this.Tick(3);
}
protected override void HandleINT()
{
base.HandleINT();
this.LowerM1();
this.LowerIORQ();
var data = this.Bus.Data;
this.RaiseIORQ();
this.RaiseM1();
this.DisableInterrupts();
switch (this.IM)
{
case 0: // i8080 equivalent
this.Execute(data);
break;
case 1:
this.Restart(7 << 3);
this.Tick(13);
break;
case 2:
this.Call(this.MEMPTR.Word = new Register16(data, this.IV).Word);
this.Tick(19);
break;
default:
throw new NotSupportedException("Invalid interrupt mode");
}
}
private static byte SetBit(byte f, StatusBits flag) => SetBit(f, (byte)flag);
private static byte SetBit(byte f, StatusBits flag, int condition) => SetBit(f, (byte)flag, condition);
private static byte SetBit(byte f, StatusBits flag, bool condition) => SetBit(f, (byte)flag, condition);
private static byte ClearBit(byte f, StatusBits flag) => ClearBit(f, (byte)flag);
private static byte ClearBit(byte f, StatusBits flag, int condition) => ClearBit(f, (byte)flag, condition);
private static byte AdjustSign(byte input, byte value) => SetBit(input, StatusBits.SF, value & (byte)StatusBits.SF);
private static byte AdjustZero(byte input, byte value) => ClearBit(input, StatusBits.ZF, value);
private static byte AdjustParity(byte input, byte value) => SetBit(input, StatusBits.PF, EvenParity(value));
private static byte AdjustSZ(byte input, byte value)
{
input = AdjustSign(input, value);
return AdjustZero(input, value);
}
private static byte AdjustSZP(byte input, byte value)
{
input = AdjustSZ(input, value);
return AdjustParity(input, value);
}
private static byte AdjustXY(byte input, byte value)
{
input = SetBit(input, StatusBits.XF, value & (byte)StatusBits.XF);
return SetBit(input, StatusBits.YF, value & (byte)StatusBits.YF);
}
private static byte AdjustSZPXY(byte input, byte value)
{
input = AdjustSZP(input, value);
return AdjustXY(input, value);
}
private static byte AdjustSZXY(byte input, byte value)
{
input = AdjustSZ(input, value);
return AdjustXY(input, value);
}
private static byte AdjustHalfCarryAdd(byte input, byte before, byte value, int calculation) => SetBit(input, StatusBits.HC, CalculateHalfCarryAdd(before, value, calculation));
private static byte AdjustHalfCarrySub(byte input, byte before, byte value, int calculation) => SetBit(input, StatusBits.HC, CalculateHalfCarrySub(before, value, calculation));
private static byte AdjustOverflowAdd(byte input, int beforeNegative, int valueNegative, int afterNegative)
{
var overflow = (beforeNegative == valueNegative) && (beforeNegative != afterNegative);
return SetBit(input, StatusBits.VF, overflow);
}
private static byte AdjustOverflowAdd(byte input, byte before, byte value, byte calculation) => AdjustOverflowAdd(input, before & (byte)StatusBits.SF, value & (byte)StatusBits.SF, calculation & (byte)StatusBits.SF);
private static byte AdjustOverflowSub(byte input, int beforeNegative, int valueNegative, int afterNegative)
{
var overflow = (beforeNegative != valueNegative) && (beforeNegative != afterNegative);
return SetBit(input, StatusBits.VF, overflow);
}
private static byte AdjustOverflowSub(byte input, byte before, byte value, byte calculation) => AdjustOverflowSub(input, before & (byte)StatusBits.SF, value & (byte)StatusBits.SF, calculation & (byte)StatusBits.SF);
private static byte RES(int n, byte operand) => ClearBit(operand, Bit(n));
private static byte SET(int n, byte operand) => SetBit(operand, Bit(n));
private void DisableInterrupts() => this.IFF1 = this.IFF2 = false;
private void EnableInterrupts() => this.IFF1 = this.IFF2 = true;
private Register16 HL2()
{
if (!this.displaced)
{
return this.HL;
}
if (this.prefixDD)
{
return this.IX;
}
// Must be FD prefix
return this.IY;
}
private Register16 RP(int rp)
{
switch (rp)
{
case 0:
return this.BC;
case 1:
return this.DE;
case 2:
return this.HL2();
case 3:
return this.SP;
default:
throw new ArgumentOutOfRangeException(nameof(rp));
}
}
private Register16 RP2(int rp)
{
switch (rp)
{
case 0:
return this.BC;
case 1:
return this.DE;
case 2:
return this.HL2();
case 3:
return this.AF;
default:
throw new ArgumentOutOfRangeException(nameof(rp));
}
}
private byte R(int r)
{
switch (r)
{
case 0:
return this.B;
case 1:
return this.C;
case 2:
return this.D;
case 3:
return this.E;
case 4:
return this.HL2().High;
case 5:
return this.HL2().Low;
case 6:
return this.BusRead(this.displaced ? this.DisplacedAddress : this.HL.Word);
case 7:
return this.A;
default:
throw new ArgumentOutOfRangeException(nameof(r));
}
}
private void R(int r, byte value)
{
switch (r)
{
case 0:
this.B = value;
break;
case 1:
this.C = value;
break;
case 2:
this.D = value;
break;
case 3:
this.E = value;
break;
case 4:
this.HL2().High = value;
break;
case 5:
this.HL2().Low = value;
break;
case 6:
this.BusWrite(this.displaced ? this.DisplacedAddress : this.HL.Word, value);
break;
case 7:
this.A = value;
break;
default:
throw new ArgumentOutOfRangeException(nameof(r));
}
}
private void R2(int r, byte value)
{
switch (r)
{
case 0:
this.B = value;
break;
case 1:
this.C = value;
break;
case 2:
this.D = value;
break;
case 3:
this.E = value;
break;
case 4:
this.H = value;
break;
case 5:
this.L = value;
break;
case 6:
this.BusWrite(this.HL, value);
break;
case 7:
this.A = value;
break;
default:
throw new ArgumentOutOfRangeException(nameof(r));
}
}
private void ExecuteCB(int x, int y, int z)
{
var memoryZ = z == 6;
var indirect = (!this.displaced && memoryZ) || this.displaced;
var direct = !indirect;
var operand = !this.displaced ? this.R(z) : this.BusRead(this.DisplacedAddress);
var update = x != 1; // BIT does not update
switch (x)
{
case 0: // rot[y] r[z]
switch (y)
{
case 0:
operand = this.RLC(operand);
break;
case 1:
operand = this.RRC(operand);
break;
case 2:
operand = this.RL(operand);
break;
case 3:
operand = this.RR(operand);
break;
case 4:
operand = this.SLA(operand);
break;
case 5:
operand = this.SRA(operand);
break;
case 6:
operand = this.SLL(operand);
break;
case 7:
operand = this.SRL(operand);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.F = AdjustSZP(this.F, operand);
this.Tick(8);
break;
case 1: // BIT y, r[z]
this.Tick(8);
this.BIT(y, operand);
if (direct)
{
this.F = AdjustXY(this.F, operand);
}
else
{
this.F = AdjustXY(this.F, this.MEMPTR.High);
this.Tick(4);
}
break;
case 2: // RES y, r[z]
this.Tick(8);
operand = RES(y, operand);
break;
case 3: // SET y, r[z]
this.Tick(8);
operand = SET(y, operand);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
if (update)
{
if (!this.displaced)
{
this.R(z, operand);
if (memoryZ)
{
this.Tick(7);
}
}
else
{
this.BusWrite(operand);
if (!memoryZ)
{
this.R2(z, operand);
}
this.Tick(15);
}
}
}
private void ExecuteED(int x, int y, int z, int p, int q)
{
switch (x)
{
case 0:
case 3: // Invalid instruction, equivalent to NONI followed by NOP
this.Tick(8);
break;
case 1:
switch (z)
{
case 0: // Input from port with 16-bit address
this.MEMPTR.Word = this.Bus.Address.Word = this.BC.Word;
this.MEMPTR.Word++;
this.ReadPort();
if (y != 6)
{
this.R(y, this.Bus.Data); // IN r[y],(C)
}
this.F = AdjustSZPXY(this.F, this.Bus.Data);
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.Tick(12);
break;
case 1: // Output to port with 16-bit address
this.MEMPTR.Word = this.Bus.Address.Word = this.BC.Word;
this.MEMPTR.Word++;
this.Bus.Data = y != 6 ? this.R(y) : (byte)0;
this.WritePort();
this.Tick(12);
break;
case 2: // 16-bit add/subtract with carry
switch (q)
{
case 0: // SBC HL, rp[p]
this.HL2().Word = this.SBC(this.HL2(), this.RP(p));
break;
case 1: // ADC HL, rp[p]
this.HL2().Word = this.ADC(this.HL2(), this.RP(p));
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.Tick(15);
break;
case 3: // Retrieve/store register pair from/to immediate address
this.Bus.Address.Word = this.FetchWord().Word;
switch (q)
{
case 0: // LD (nn), rp[p]
this.SetWord(this.RP(p));
break;
case 1: // LD rp[p], (nn)
this.RP(p).Word = this.GetWord().Word;
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.Tick(20);
break;
case 4: // Negate accumulator
this.NEG();
this.Tick(8);
break;
case 5: // Return from interrupt
switch (y)
{
case 1:
this.RetI(); // RETI
break;
default:
this.RetN(); // RETN
break;
}
this.Tick(14);
break;
case 6: // Set interrupt mode
switch (y)
{
case 0:
case 1:
case 4:
case 5:
this.IM = 0;
break;
case 2:
case 6:
this.IM = 1;
break;
case 3:
case 7:
this.IM = 2;
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.Tick(8);
break;
case 7: // Assorted ops
switch (y)
{
case 0: // LD I,A
this.IV = this.A;
this.Tick(9);
break;
case 1: // LD R,A
this.REFRESH = this.A;
this.Tick(9);
break;
case 2: // LD A,I
this.F = AdjustSZXY(this.F, this.A = this.IV);
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.F = SetBit(this.F, StatusBits.PF, this.IFF2);
this.Tick(9);
break;
case 3: // LD A,R
this.F = AdjustSZXY(this.F, this.A = this.REFRESH);
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.F = SetBit(this.F, StatusBits.PF, this.IFF2);
this.Tick(9);
break;
case 4: // RRD
this.RRD();
this.Tick(18);
break;
case 5: // RLD
this.RLD();
this.Tick(18);
break;
case 6: // NOP
case 7: // NOP
this.Tick(4);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 2:
switch (z)
{
case 0: // LD
switch (y)
{
case 4: // LDI
this.LDI();
break;
case 5: // LDD
this.LDD();
break;
case 6: // LDIR
if (this.LDIR())
{
this.MEMPTR.Word = --this.PC.Word;
--this.PC.Word;
this.Tick(5);
}
break;
case 7: // LDDR
if (this.LDDR())
{
this.MEMPTR.Word = --this.PC.Word;
--this.PC.Word;
this.Tick(5);
}
break;
}
break;
case 1: // CP
switch (y)
{
case 4: // CPI
this.CPI();
break;
case 5: // CPD
this.CPD();
break;
case 6: // CPIR
if (this.CPIR())
{
this.MEMPTR.Word = --this.PC.Word;
--this.PC.Word;
this.Tick(5);
}
break;
case 7: // CPDR
if (this.CPDR())
{
this.MEMPTR.Word = --this.PC.Word;
--this.PC.Word;
this.Tick(5);
}
else
{
this.MEMPTR.Word = (ushort)(this.PC.Word - 2);
}
break;
}
break;
case 2: // IN
switch (y)
{
case 4: // INI
this.INI();
break;
case 5: // IND
this.IND();
break;
case 6: // INIR
if (this.INIR())
{
this.PC.Word -= 2;
this.Tick(5);
}
break;
case 7: // INDR
if (this.INDR())
{
this.PC.Word -= 2;
this.Tick(5);
}
break;
}
break;
case 3: // OUT
switch (y)
{
case 4: // OUTI
this.OUTI();
break;
case 5: // OUTD
this.OUTD();
break;
case 6: // OTIR
if (this.OTIR())
{
this.PC.Word -= 2;
this.Tick(5);
}
break;
case 7: // OTDR
if (this.OTDR())
{
this.PC.Word -= 2;
this.Tick(5);
}
break;
}
break;
}
this.Tick(16);
break;
}
}
private void ExecuteOther(int x, int y, int z, int p, int q)
{
var memoryY = y == 6;
var memoryZ = z == 6;
switch (x)
{
case 0:
switch (z)
{
case 0: // Relative jumps and assorted ops
switch (y)
{
case 0: // NOP
if (this.prefixDD)
{
this.Tick(4);
}
this.Tick(4);
break;
case 1: // EX AF AF'
this.ExxAF();
this.Tick(4);
break;
case 2: // DJNZ d
if (this.JumpRelativeConditional(--this.B != 0))
{
this.Tick(5);
}
this.Tick(8);
break;
case 3: // JR d
this.JumpRelative((sbyte)this.FetchByte());
this.Tick(12);
break;
case 4: // JR cc,d
case 5:
case 6:
case 7:
if (this.JumpRelativeConditionalFlag(y - 4))
{
this.Tick(5);
}
this.Tick(5);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 1: // 16-bit load immediate/add
switch (q)
{
case 0: // LD rp,nn
this.RP(p).Word = this.FetchWord().Word;
this.Tick(10);
break;
case 1: // ADD HL,rp
this.HL2().Word = this.Add(this.HL2(), this.RP(p));
this.Tick(11);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 2: // Indirect loading
switch (q)
{
case 0:
switch (p)
{
case 0: // LD (BC),A
this.MEMPTR.Word = this.Bus.Address.Word = this.BC.Word;
++this.MEMPTR.Word;
this.MEMPTR.High = this.Bus.Data = this.A;
this.BusWrite();
this.Tick(7);
break;
case 1: // LD (DE),A
this.MEMPTR.Word = this.Bus.Address.Word = this.DE.Word;
++this.MEMPTR.Word;
this.MEMPTR.High = this.Bus.Data = this.A;
this.BusWrite();
this.Tick(7);
break;
case 2: // LD (nn),HL
this.Bus.Address.Word = this.FetchWord().Word;
this.SetWord(this.HL2());
this.Tick(16);
break;
case 3: // LD (nn),A
this.MEMPTR.Word = this.Bus.Address.Word = this.FetchWord().Word;
++this.MEMPTR.Word;
this.MEMPTR.High = this.Bus.Data = this.A;
this.BusWrite();
this.Tick(13);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 1:
switch (p)
{
case 0: // LD A,(BC)
this.MEMPTR.Word = this.Bus.Address.Word = this.BC.Word;
++this.MEMPTR.Word;
this.A = this.BusRead();
this.Tick(7);
break;
case 1: // LD A,(DE)
this.MEMPTR.Word = this.Bus.Address.Word = this.DE.Word;
++this.MEMPTR.Word;
this.A = this.BusRead();
this.Tick(7);
break;
case 2: // LD HL,(nn)
this.Bus.Address.Word = this.FetchWord().Word;
this.HL2().Word = this.GetWord().Word;
this.Tick(16);
break;
case 3: // LD A,(nn)
this.MEMPTR.Word = this.Bus.Address.Word = this.FetchWord().Word;
++this.MEMPTR.Word;
this.A = this.BusRead();
this.Tick(13);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 3: // 16-bit INC/DEC
switch (q)
{
case 0: // INC rp
++this.RP(p).Word;
break;
case 1: // DEC rp
--this.RP(p).Word;
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.Tick(6);
break;
case 4: // 8-bit INC
if (this.displaced && memoryY)
{
this.FetchDisplacement();
}
this.R(y, this.Increment(this.R(y)));
this.Tick(4);
break;
case 5: // 8-bit DEC
if (memoryY)
{
this.Tick(7);
if (this.displaced)
{
this.FetchDisplacement();
}
}
this.R(y, this.Decrement(this.R(y)));
this.Tick(4);
break;
case 6: // 8-bit load immediate
if (memoryY)
{
this.Tick(3);
if (this.displaced)
{
this.FetchDisplacement();
}
}
this.R(y, this.FetchByte()); // LD r,n
this.Tick(7);
break;
case 7: // Assorted operations on accumulator/flags
switch (y)
{
case 0:
this.A = this.RLC(this.A);
break;
case 1:
this.A = this.RRC(this.A);
break;
case 2:
this.A = this.RL(this.A);
break;
case 3:
this.A = this.RR(this.A);
break;
case 4:
this.DAA();
break;
case 5:
this.CPL();
break;
case 6:
this.SCF();
break;
case 7:
this.CCF();
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.Tick(4);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 1: // 8-bit loading
if (!(memoryZ && memoryY))
{
var normal = true;
if (this.displaced)
{
if (memoryZ || memoryY)
{
this.FetchDisplacement();
}
if (memoryZ)
{
switch (y)
{
case 4:
this.H = this.R(z);
normal = false;
break;
case 5:
this.L = this.R(z);
normal = false;
break;
}
}
if (memoryY)
{
switch (z)
{
case 4:
this.R(y, this.H);
normal = false;
break;
case 5:
this.R(y, this.L);
normal = false;
break;
}
}
}
if (normal)
{
this.R(y, this.R(z));
}
// M operations
if (memoryY || memoryZ)
{
this.Tick(3);
}
}
else
{
this.LowerHALT(); // Exception (replaces LD (HL), (HL))
}
this.Tick(4);
break;
case 2:
{ // Operate on accumulator and register/memory location
if (memoryZ)
{
this.Tick(3);
if (this.displaced)
{
this.FetchDisplacement();
}
}
var value = this.R(z);
switch (y)
{
case 0: // ADD A,r
this.A = this.Add(this.A, value);
break;
case 1: // ADC A,r
this.A = this.ADC(this.A, value);
break;
case 2: // SUB r
this.A = this.SUB(this.A, value);
break;
case 3: // SBC A,r
this.A = this.SBC(this.A, value);
break;
case 4: // AND r
this.AndR(value);
break;
case 5: // XOR r
this.XorR(value);
break;
case 6: // OR r
this.OrR(value);
break;
case 7: // CP r
this.Compare(value);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.Tick(4);
break;
}
case 3:
switch (z)
{
case 0: // Conditional return
if (this.ReturnConditionalFlag(y))
{
this.Tick(6);
}
this.Tick(5);
break;
case 1: // POP & various ops
switch (q)
{
case 0: // POP rp2[p]
this.RP2(p).Word = this.PopWord().Word;
this.Tick(10);
break;
case 1:
switch (p)
{
case 0: // RET
this.Return();
this.Tick(10);
break;
case 1: // EXX
this.Exx();
this.Tick(4);
break;
case 2: // JP HL
this.Jump(this.HL2().Word);
this.Tick(4);
break;
case 3: // LD SP,HL
this.SP.Word = this.HL2().Word;
this.Tick(4);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 2: // Conditional jump
this.JumpConditionalFlag(y);
this.Tick(10);
break;
case 3: // Assorted operations
switch (y)
{
case 0: // JP nn
this.Jump(this.MEMPTR.Word = this.FetchWord().Word);
this.Tick(10);
break;
case 1: // CB prefix
this.prefixCB = true;
if (this.displaced)
{
this.FetchDisplacement();
}
else
{
this.LowerM1();
}
this.Execute(this.FetchByte());
break;
case 2: // OUT (n),A
this.WritePort(this.FetchByte());
this.Tick(11);
break;
case 3: // IN A,(n)
this.A = this.ReadPort(this.FetchByte());
this.Tick(11);
break;
case 4: // EX (SP),HL
this.XHTL(this.HL2());
this.Tick(19);
break;
case 5: // EX DE,HL
(this.DE.Word, this.HL.Word) = (this.HL.Word, this.DE.Word);
this.Tick(4);
break;
case 6: // DI
this.DisableInterrupts();
this.Tick(4);
break;
case 7: // EI
this.EnableInterrupts();
this.Tick(4);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 4: // Conditional call: CALL cc[y], nn
if (this.CallConditionalFlag(y))
{
this.Tick(7);
}
this.Tick(10);
break;
case 5: // PUSH & various ops
switch (q)
{
case 0: // PUSH rp2[p]
this.PushWord(this.RP2(p));
this.Tick(11);
break;
case 1:
switch (p)
{
case 0: // CALL nn
this.Call(this.MEMPTR.Word = this.FetchWord().Word);
this.Tick(17);
break;
case 1: // DD prefix
this.displaced = this.prefixDD = true;
this.LowerM1();
this.Execute(this.FetchByte());
break;
case 2: // ED prefix
this.prefixED = true;
this.LowerM1();
this.Execute(this.FetchByte());
break;
case 3: // FD prefix
this.displaced = true;
this.LowerM1();
this.Execute(this.FetchByte());
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
case 6:
{ // Operate on accumulator and immediate operand: alu[y] n
var operand = this.FetchByte();
switch (y)
{
case 0: // ADD A,n
this.A = this.Add(this.A, operand);
break;
case 1: // ADC A,n
this.A = this.ADC(this.A, operand);
break;
case 2: // SUB n
this.A = this.SUB(this.A, operand);
break;
case 3: // SBC A,n
this.A = this.SBC(this.A, operand);
break;
case 4: // AND n
this.AndR(operand);
break;
case 5: // XOR n
this.XorR(operand);
break;
case 6: // OR n
this.OrR(operand);
break;
case 7: // CP n
this.Compare(operand);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
this.Tick(7);
break;
}
case 7: // Restart: RST y * 8
this.Restart((byte)(y << 3));
this.Tick(11);
break;
default:
throw new NotSupportedException("Invalid operation mode");
}
break;
}
}
private void HandleNMI()
{
this.RaiseNMI();
this.RaiseHALT();
this.IFF1 = false;
this.LowerM1();
var discarded = this.Bus.Data;
this.RaiseM1();
this.Restart(0x66);
this.Tick(13);
}
private void FetchDisplacement() => this.displacement = (sbyte)this.FetchByte();
private byte Subtract(byte operand, byte value, int carry = 0)
{
this.intermediate.Word = (ushort)(operand - value - carry);
var result = this.intermediate.Low;
this.F = AdjustHalfCarrySub(this.F, operand, value, result);
this.F = AdjustOverflowSub(this.F, operand, value, result);
this.F = SetBit(this.F, StatusBits.NF);
this.F = SetBit(this.F, StatusBits.CF, this.intermediate.High & (byte)StatusBits.CF);
this.F = AdjustSZ(this.F, result);
return result;
}
private byte Increment(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF);
var result = ++operand;
this.F = AdjustSZXY(this.F, result);
this.F = SetBit(this.F, StatusBits.VF, result == (byte)Bits.Bit7);
this.F = ClearBit(this.F, StatusBits.HC, LowNibble(result));
return result;
}
private byte Decrement(byte operand)
{
this.F = SetBit(this.F, StatusBits.NF);
this.F = ClearBit(this.F, StatusBits.HC, LowNibble(operand));
var result = --operand;
this.F = AdjustSZXY(this.F, result);
this.F = SetBit(this.F, StatusBits.VF, result == (byte)Mask.Mask7);
return result;
}
private void RetN()
{
this.Return();
this.IFF1 = this.IFF2;
}
private void RetI() => this.RetN();
private bool JumpRelativeConditionalFlag(int flag)
{
switch (flag)
{
case 0: // NZ
return this.JumpRelativeConditional((this.F & (byte)StatusBits.ZF) == 0);
case 1: // Z
return this.JumpRelativeConditional((this.F & (byte)StatusBits.ZF) != 0);
case 2: // NC
return this.JumpRelativeConditional((this.F & (byte)StatusBits.CF) == 0);
case 3: // C
return this.JumpRelativeConditional((this.F & (byte)StatusBits.CF) != 0);
default:
throw new ArgumentOutOfRangeException(nameof(flag));
}
}
private bool ReturnConditionalFlag(int flag)
{
switch (flag)
{
case 0: // NZ
return this.ReturnConditional((this.F & (byte)StatusBits.ZF) == 0);
case 1: // Z
return this.ReturnConditional((this.F & (byte)StatusBits.ZF) != 0);
case 2: // NC
return this.ReturnConditional((this.F & (byte)StatusBits.CF) == 0);
case 3: // C
return this.ReturnConditional((this.F & (byte)StatusBits.CF) != 0);
case 4: // PO
return this.ReturnConditional((this.F & (byte)StatusBits.PF) == 0);
case 5: // PE
return this.ReturnConditional((this.F & (byte)StatusBits.PF) != 0);
case 6: // P
return this.ReturnConditional((this.F & (byte)StatusBits.SF) == 0);
case 7: // M
return this.ReturnConditional((this.F & (byte)StatusBits.SF) != 0);
default:
throw new ArgumentOutOfRangeException(nameof(flag));
}
}
private bool JumpConditionalFlag(int flag)
{
switch (flag)
{
case 0: // NZ
return this.JumpConditional((this.F & (byte)StatusBits.ZF) == 0);
case 1: // Z
return this.JumpConditional((this.F & (byte)StatusBits.ZF) != 0);
case 2: // NC
return this.JumpConditional((this.F & (byte)StatusBits.CF) == 0);
case 3: // C
return this.JumpConditional((this.F & (byte)StatusBits.CF) != 0);
case 4: // PO
return this.JumpConditional((this.F & (byte)StatusBits.PF) == 0);
case 5: // PE
return this.JumpConditional((this.F & (byte)StatusBits.PF) != 0);
case 6: // P
return this.JumpConditional((this.F & (byte)StatusBits.SF) == 0);
case 7: // M
return this.JumpConditional((this.F & (byte)StatusBits.SF) != 0);
default:
throw new ArgumentOutOfRangeException(nameof(flag));
}
}
private bool CallConditionalFlag(int flag)
{
switch (flag)
{
case 0: // NZ
return this.CallConditional((this.F & (byte)StatusBits.ZF) == 0);
case 1: // Z
return this.CallConditional((this.F & (byte)StatusBits.ZF) != 0);
case 2: // NC
return this.CallConditional((this.F & (byte)StatusBits.CF) == 0);
case 3: // C
return this.CallConditional((this.F & (byte)StatusBits.CF) != 0);
case 4: // PO
return this.CallConditional((this.F & (byte)StatusBits.PF) == 0);
case 5: // PE
return this.CallConditional((this.F & (byte)StatusBits.PF) != 0);
case 6: // P
return this.CallConditional((this.F & (byte)StatusBits.SF) == 0);
case 7: // M
return this.CallConditional((this.F & (byte)StatusBits.SF) != 0);
default:
throw new ArgumentOutOfRangeException(nameof(flag));
}
}
private ushort SBC(Register16 operand, Register16 value)
{
var subtraction = operand.Word - value.Word - (this.F & (byte)StatusBits.CF);
this.intermediate.Word = (ushort)subtraction;
this.F = SetBit(this.F, StatusBits.NF);
this.F = ClearBit(this.F, StatusBits.ZF, this.intermediate.Word);
this.F = SetBit(this.F, StatusBits.CF, subtraction & (int)Bits.Bit16);
this.F = AdjustHalfCarrySub(this.F, operand.High, value.High, this.intermediate.High);
this.F = AdjustXY(this.F, this.intermediate.High);
var beforeNegative = operand.High & (byte)StatusBits.SF;
var valueNegative = value.High & (byte)StatusBits.SF;
var afterNegative = this.intermediate.High & (byte)StatusBits.SF;
this.F = SetBit(this.F, StatusBits.SF, afterNegative);
this.F = AdjustOverflowSub(this.F, beforeNegative, valueNegative, afterNegative);
this.MEMPTR.Word = (ushort)(operand.Word + 1);
return this.intermediate.Word;
}
private ushort ADC(Register16 operand ,Register16 value)
{
this.Add(operand, value, this.F & (byte)StatusBits.CF); // Leaves result in intermediate anyway
this.F = ClearBit(this.F, StatusBits.ZF, this.intermediate.Word);
var beforeNegative = operand.High & (byte)StatusBits.SF;
var valueNegative = value.High & (byte)StatusBits.SF;
var afterNegative = this.intermediate.High & (byte)StatusBits.SF;
this.F = SetBit(this.F, StatusBits.SF, afterNegative);
this.F = AdjustOverflowAdd(this.F, beforeNegative, valueNegative, afterNegative);
return this.intermediate.Word;
}
private ushort Add(Register16 operand, Register16 value, int carry = 0)
{
var addition = operand.Word + value.Word + carry;
this.intermediate.Word = (ushort)addition;
this.F = ClearBit(this.F, StatusBits.NF);
this.F = SetBit(this.F, StatusBits.CF, addition & (int)Bits.Bit16);
this.F = AdjustHalfCarryAdd(this.F, operand.High, value.High, this.intermediate.High);
this.F = AdjustXY(this.F, this.intermediate.High);
this.MEMPTR.Word = (ushort)(operand.Word + 1);
return this.intermediate.Word;
}
private byte Add(byte operand, byte value, int carry = 0)
{
this.intermediate.Word = (ushort)(operand + value + carry);
var result = this.intermediate.Low;
this.F = AdjustHalfCarryAdd(this.F, operand, value, result);
this.F = AdjustOverflowAdd(this.F, operand, value, result);
this.F = ClearBit(this.F, StatusBits.NF);
this.F = SetBit(this.F, StatusBits.CF, this.intermediate.High & (byte)StatusBits.CF);
this.F = AdjustSZXY(this.F, result);
return result;
}
private byte ADC(byte operand, byte value) => this.Add(operand, value, this.F & (byte)StatusBits.CF);
private byte SUB(byte operand, byte value, int carry = 0)
{
var subtraction = this.Subtract(operand, value, carry);
this.F = AdjustXY(this.F, subtraction);
return subtraction;
}
private byte SBC(byte operand, byte value) => this.SUB(operand, value, this.F & (byte)StatusBits.CF);
private void AndR(byte value)
{
this.F = SetBit(this.F, StatusBits.HC);
this.F = ClearBit(this.F, StatusBits.CF | StatusBits.NF);
this.F = AdjustSZPXY(this.F, this.A &= value);
}
private void XorR(byte value)
{
this.F = ClearBit(this.F, StatusBits.HC | StatusBits.CF | StatusBits.NF);
this.F = AdjustSZPXY(this.F, this.A ^= value);
}
private void OrR(byte value)
{
this.F = ClearBit(this.F, StatusBits.HC | StatusBits.CF | StatusBits.NF);
this.F = AdjustSZPXY(this.F, this.A |= value);
}
private void Compare(byte value)
{
this.Subtract(this.A, value);
this.F = AdjustXY(this.F, value);
}
private byte RLC(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
var carry = operand & (byte)Bits.Bit7;
this.F = SetBit(this.F, StatusBits.CF, carry);
var result = (byte)((operand << 1) | (carry >> 7));
this.F = AdjustXY(this.F, result);
return result;
}
private byte RRC(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
var carry = operand & (byte)Bits.Bit0;
this.F = SetBit(this.F, StatusBits.CF, carry);
var result = (byte)((operand >> 1) | (carry << 7));
this.F = AdjustXY(this.F, result);
return result;
}
private byte RL(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
var carry = this.F & (byte)StatusBits.CF;
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit7);
var result = (byte)((operand << 1) | carry);
this.F = AdjustXY(this.F, result);
return result;
}
private byte RR(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
var carry = this.F & (byte)StatusBits.CF;
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit0);
var result = (byte)((operand >> 1) | (carry << 7));
this.F = AdjustXY(this.F, result);
return result;
}
private byte SLA(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit7);
var result = (byte)(operand << 1);
this.F = AdjustXY(this.F, result);
return result;
}
private byte SRA(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit0);
var result = (byte)((operand >> 1) | (operand & (byte)Bits.Bit7));
this.F = AdjustXY(this.F, result);
return result;
}
private byte SLL(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit7);
var result = (byte)((operand << 1) | (byte)Bits.Bit0);
this.F = AdjustXY(this.F, result);
return result;
}
private byte SRL(byte operand)
{
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit0);
var result = (byte)((operand >> 1) & ~(byte)Bits.Bit7);
this.F = AdjustXY(this.F, result);
this.F = SetBit(this.F, StatusBits.ZF, result);
return result;
}
private void BIT(int n, byte operand)
{
this.F = SetBit(this.F, StatusBits.HC);
this.F = ClearBit(this.F, StatusBits.NF);
var discarded = (byte)(operand & Bit(n));
this.F = AdjustSZ(this.F, discarded);
this.F = ClearBit(this.F, StatusBits.PF, discarded);
}
private void DAA()
{
var updated = this.A;
var lowAdjust = ((this.F & (byte)StatusBits.HC) != 0) || (LowNibble(this.A) > 9);
var highAdjust = ((this.F & (byte)StatusBits.CF) != 0) || (this.A > 0x99);
if ((this.F & (byte)StatusBits.NF) != 0)
{
if (lowAdjust)
{
updated -= 6;
}
if (highAdjust)
{
updated -= 0x60;
}
}
else
{
if (lowAdjust)
{
updated += 6;
}
if (highAdjust)
{
updated += 0x60;
}
}
this.F = (byte)((this.F & (byte)(StatusBits.CF | StatusBits.NF)) | (this.A > 0x99 ? (byte)StatusBits.CF : 0) | ((this.A ^ updated) & (byte)StatusBits.HC));
this.F = AdjustSZPXY(this.F, this.A = updated);
}
private void SCF()
{
this.F = SetBit(this.F, StatusBits.CF);
this.F = ClearBit(this.F, StatusBits.HC | StatusBits.NF);
this.F = AdjustXY(this.F, this.A);
}
private void CCF()
{
this.F = ClearBit(this.F, StatusBits.NF);
var carry = this.F & (byte)StatusBits.CF;
this.F = SetBit(this.F, StatusBits.HC, carry);
this.F = ClearBit(this.F, StatusBits.CF, carry);
this.F = AdjustXY(this.F, this.A);
}
private void CPL()
{
this.F = SetBit(this.F, StatusBits.HC | StatusBits.NF);
this.F = AdjustXY(this.F, this.A = (byte)~this.A);
}
private void XHTL(Register16 exchange)
{
this.MEMPTR.Low = this.BusRead(this.SP.Word);
++this.Bus.Address.Word;
this.MEMPTR.High = this.BusRead();
this.BusWrite(exchange.High);
exchange.High = this.MEMPTR.High;
--this.Bus.Address.Word;
this.BusWrite(exchange.Low);
exchange.Low = this.MEMPTR.Low;
}
private void BlockCompare(ushort source, ushort counter)
{
var value = this.BusRead(source);
var result = (byte)(this.A - value);
this.F = SetBit(this.F, StatusBits.PF, counter);
this.F = AdjustSZ(this.F, result);
this.F = AdjustHalfCarrySub(this.F, this.A, value, result);
this.F = SetBit(this.F, StatusBits.NF);
result -= (byte)((this.F & (byte)StatusBits.HC) >> 4);
this.F = SetBit(this.F, StatusBits.YF, result & (byte)Bits.Bit1);
this.F = SetBit(this.F, StatusBits.XF, result & (byte)Bits.Bit3);
}
private void CPI()
{
this.BlockCompare(this.HL.Word++, --this.BC.Word);
++this.MEMPTR.Word;
}
private bool CPIR()
{
this.CPI();
return ((this.F & (byte)StatusBits.PF) != 0) && ((this.F & (byte)StatusBits.ZF) == 0); // See CPI
}
private void CPD()
{
this.BlockCompare(this.HL.Word--, --this.BC.Word);
--this.MEMPTR.Word;
}
private bool CPDR()
{
this.CPD();
return ((this.F & (byte)StatusBits.PF) != 0) && ((this.F & (byte)StatusBits.ZF) == 0); // See CPD
}
private void BlockLoad(ushort source, ushort destination, ushort counter)
{
var value = this.BusRead(source);
this.BusWrite(destination, value);
var xy = this.A + value;
this.F = SetBit(this.F, StatusBits.XF, xy & (int)Bits.Bit3);
this.F = SetBit(this.F, StatusBits.YF, xy & (int)Bits.Bit1);
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
this.F = SetBit(this.F, StatusBits.PF, counter);
}
private void LDI() => this.BlockLoad(this.HL.Word++, this.DE.Word++, --this.BC.Word);
private bool LDIR()
{
this.LDI();
return (this.F & (byte)StatusBits.PF) != 0; // See LDI
}
private void LDD() => this.BlockLoad(this.HL.Word--, this.DE.Word--, --this.BC.Word);
private bool LDDR()
{
this.LDD();
return (this.F & (byte)StatusBits.PF) != 0; // See LDD
}
private void BlockIn(Register16 source, ushort destination)
{
this.MEMPTR.Word = this.Bus.Address.Word = source.Word;
var value = this.ReadPort();
this.BusWrite(destination, value);
source.High = this.Decrement(source.High);
this.F = SetBit(this.F, StatusBits.NF);
}
private void INI()
{
this.BlockIn(this.BC, this.HL.Word++);
++this.MEMPTR.Word;
}
private bool INIR()
{
this.INI();
return (this.F & (byte)StatusBits.ZF) == 0; // See INI
}
private void IND()
{
this.BlockIn(this.BC, this.HL.Word--);
--this.MEMPTR.Word;
}
private bool INDR()
{
this.IND();
return (this.F & (byte)StatusBits.ZF) == 0; // See IND
}
private void BlockOut(ushort source, Register16 destination)
{
var value = this.BusRead(source);
destination.High = this.Decrement(destination.High);
this.Bus.Address.Word = destination.Word;
this.WritePort();
this.MEMPTR.Word = destination.Word;
this.F = SetBit(this.F, StatusBits.NF, value & (byte)Bits.Bit7);
this.F = SetBit(this.F, StatusBits.HC | StatusBits.CF, (this.L + value) > 0xff);
this.F = AdjustParity(this.F, (byte)(((value + this.L) & (int)Mask.Mask3) ^ this.B));
}
private void OUTI()
{
this.BlockOut(this.HL.Word++, this.BC);
++this.MEMPTR.Word;
}
private bool OTIR()
{
this.OUTI();
return (this.F & (byte)StatusBits.ZF) == 0; // See OUTI
}
private void OUTD()
{
this.BlockOut(this.HL.Word--, this.BC);
--this.MEMPTR.Word;
}
private bool OTDR()
{
this.OUTD();
return (this.F & (byte)StatusBits.ZF) == 0; // See OUTD
}
private void NEG()
{
this.F = SetBit(this.F, StatusBits.PF, this.A == (byte)Bits.Bit7);
this.F = SetBit(this.F, StatusBits.CF, this.A);
this.F = SetBit(this.F, StatusBits.NF);
var original = this.A;
this.A = (byte)(~this.A + 1); // two's complement
this.F = AdjustHalfCarrySub(this.F, (byte)0, original, this.A);
this.F = AdjustOverflowSub(this.F, (byte)0, original, this.A);
this.F = AdjustSZXY(this.F, this.A);
}
private void RRD()
{
this.MEMPTR.Word = this.Bus.Address.Word = this.HL.Word;
++this.MEMPTR.Word;
var memory = this.BusRead();
this.BusWrite((byte)(PromoteNibble(this.A) | HighNibble(memory)));
this.A = (byte)(HigherNibble(this.A) | LowerNibble(memory));
this.F = AdjustSZPXY(this.F, this.A);
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
}
private void RLD()
{
this.MEMPTR.Word = this.Bus.Address.Word = this.HL.Word;
++this.MEMPTR.Word;
var memory = this.BusRead();
this.BusWrite((byte)(PromoteNibble(memory) | LowNibble(this.A)));
this.A = (byte)(HigherNibble(this.A) | HighNibble(memory));
this.F = AdjustSZPXY(this.F, this.A);
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
}
private void WritePort(byte port)
{
this.MEMPTR.Word = this.Bus.Address.Word = new Register16(port, this.A).Word;
this.Bus.Data = this.A;
this.WritePort();
++this.MEMPTR.Low;
}
private void WritePort()
{
this.LowerIORQ();
this.LowerWR();
this.ports.Write(this.Bus.Address.Low, this.Bus.Data);
this.RaiseWR();
this.RaiseIORQ();
}
private byte ReadPort(byte port)
{
this.MEMPTR.Word = this.Bus.Address.Word = new Register16(port, this.A).Word;
++this.MEMPTR.Low;
return this.ReadPort();
}
private byte ReadPort()
{
this.LowerIORQ();
this.LowerRD();
var returned = this.Bus.Data = this.ports.Read(this.Bus.Address.Low);
this.RaiseRD();
this.RaiseIORQ();
return returned;
}
}
}