/// <summary>
/// The LDIR instruction.
/// </summary>
byte LDIR()
{
FetchFinished();
var sourceAddress = Registers.HL;
var destAddress = Registers.DE;
var counter = Registers.BC;
var value = ProcessorAgent.ReadFromMemory(sourceAddress.ToUShort());
ProcessorAgent.WriteToMemory(destAddress.ToUShort(), value);
Registers.HL = sourceAddress.Inc();
Registers.DE = destAddress.Inc();
counter = counter.Dec();
Registers.BC = counter;
Registers.HF = 0;
Registers.NF = 0;
Registers.PF = (counter != 0);
var valuePlusA = value.Add(Registers.A).GetLowByte();
Registers.Flag3 = valuePlusA.GetBit(3);
Registers.Flag5 = valuePlusA.GetBit(1);
if (counter != 0)
{
Registers.PC = Registers.PC.Sub(2);
return(21);
}
return(16);
}
/// <summary>
/// The INDR instruction.
/// </summary>
byte INDR()
{
FetchFinished();
var portNumber = Registers.C;
var address = Registers.HL;
var value = ProcessorAgent.ReadFromPort(portNumber);
ProcessorAgent.WriteToMemory((ushort)address, value);
Registers.HL--;
var counter = Registers.B;
counter = (byte)(counter - 1);
Registers.B = counter;
Registers.ZF = (counter == 0);
Registers.NF = 1;
Registers.SF = counter.GetBit(7);
SetFlags3and5From(counter);
if (counter != 0)
{
Registers.PC = (ushort)(Registers.PC - 2);
return(21);
}
return(16);
}
/// <summary>
/// The INDR instruction.
/// </summary>
byte INDR()
{
FetchFinished();
var portNumber = Registers.C;
var address = Registers.HL;
var value = ProcessorAgent.ReadFromPort(portNumber);
ProcessorAgent.WriteToMemory(address.ToUShort(), value);
Registers.HL = address.Dec();
var counter = Registers.B;
counter = counter.Dec();
Registers.B = counter;
Registers.ZF = (counter == 0);
Registers.NF = 1;
Registers.SF = counter.GetBit(7);
SetFlags3and5From(counter);
if (counter != 0)
{
Registers.PC = Registers.PC.Sub(2);
return(21);
}
return(16);
}
/// <summary>
/// The LDIR instruction.
/// </summary>
byte LDIR()
{
FetchFinished();
var sourceAddress = Registers.HL;
var destAddress = Registers.DE;
var counter = Registers.BC;
var value = ProcessorAgent.ReadFromMemory((ushort)sourceAddress);
ProcessorAgent.WriteToMemory((ushort)destAddress, value);
Registers.HL = (short)(sourceAddress + 1);
Registers.DE = (short)(destAddress + 1);
counter--;
Registers.BC = counter;
Registers.HF = 0;
Registers.NF = 0;
Registers.PF = (counter != 0);
var valuePlusA = (byte)(value + Registers.A);
Registers.Flag3 = valuePlusA.GetBit(3);
Registers.Flag5 = valuePlusA.GetBit(1);
if (counter != 0)
{
Registers.PC = (ushort)(Registers.PC - 2);
return(21);
}
return(16);
}
/// <summary>
/// The LD (nn),A instruction.
/// </summary>
private byte LD_aa_A()
{
var address = FetchWord().ToUShort();
FetchFinished();
ProcessorAgent.WriteToMemory(address, Registers.A);
return(13);
}
/// <summary>
/// The LD (DE),A instruction.
/// </summary>
byte LD_aDE_A()
{
FetchFinished();
var newValue = Registers.A;
var address = Registers.DE.ToUShort();
ProcessorAgent.WriteToMemory(address, newValue);
return(7);
}
/// <summary>
/// The LD (HL),A instruction.
/// </summary>
byte LD_aHL_A()
{
FetchFinished();
var newValue = Registers.A;
var address = (ushort)Registers.HL;
ProcessorAgent.WriteToMemory(address, newValue);
return(7);
}
/// <summary>
/// The LD (HL),n instruction.
/// </summary>
private byte LD_aHL_N()
{
var newValue = ProcessorAgent.FetchNextOpcode();
FetchFinished();
var address = (ushort)Registers.HL;
ProcessorAgent.WriteToMemory(address, newValue);
return(10);
}
/// <summary>
/// The LD (IY+n),L instruction.
/// </summary>
byte LD_aIY_plus_n_L()
{
var offset = ProcessorAgent.FetchNextOpcode();
FetchFinished();
var newValue = Registers.L;
var address = Registers.IY.ToUShort().Add(offset.ToSignedByte());
ProcessorAgent.WriteToMemory(address, newValue);
return(19);
}
/// <summary>
/// The LD (IY+n),L instruction.
/// </summary>
byte LD_aIY_plus_n_L()
{
var offset = ProcessorAgent.FetchNextOpcode();
FetchFinished();
var newValue = Registers.L;
var address = (ushort)(Registers.IY + (SByte)offset);
ProcessorAgent.WriteToMemory(address, newValue);
return(19);
}
/// <summary>
/// The PUSH DE instruction.
/// </summary>
private byte PUSH_DE()
{
FetchFinished();
var valueToPush = Registers.DE;
var sp = Registers.SP.Dec();
ProcessorAgent.WriteToMemory(sp.ToUShort(), valueToPush.GetHighByte());
sp = sp.Dec();
ProcessorAgent.WriteToMemory(sp.ToUShort(), valueToPush.GetLowByte());
Registers.SP = sp;
return(11);
}
/// <summary>
/// The PUSH DE instruction.
/// </summary>
private byte PUSH_DE()
{
FetchFinished();
var valueToPush = Registers.DE;
var sp = (ushort)(Registers.SP - 1);
ProcessorAgent.WriteToMemory(sp, valueToPush.GetHighByte());
sp--;
ProcessorAgent.WriteToMemory(sp, valueToPush.GetLowByte());
Registers.SP = (short)sp;
return(11);
}
/// <summary>
/// The RST 20h instruction.
/// </summary>
private byte RST_20()
{
FetchFinished();
var valueToPush = (short)Registers.PC;
var sp = (ushort)(Registers.SP - 1);
ProcessorAgent.WriteToMemory(sp, valueToPush.GetHighByte());
sp--;
ProcessorAgent.WriteToMemory(sp, valueToPush.GetLowByte());
Registers.SP = (short)sp;
Registers.PC = 0x20;
return(11);
}
/// <summary>
/// The CALL instruction.
/// </summary>
private byte CALL_nn()
{
var newAddress = FetchWord().ToUShort();
FetchFinished();
var valueToPush = Registers.PC.ToShort();
var sp = Registers.SP.Dec();
ProcessorAgent.WriteToMemory(sp.ToUShort(), valueToPush.GetHighByte());
sp = sp.Dec();
ProcessorAgent.WriteToMemory(sp.ToUShort(), valueToPush.GetLowByte());
Registers.SP = sp;
Registers.PC = newAddress;
return(17);
}
/// <summary>
/// The CALL instruction.
/// </summary>
private byte CALL_nn()
{
var newAddress = (ushort)FetchWord();
FetchFinished();
var valueToPush = (short)Registers.PC;
var sp = (ushort)(Registers.SP - 1);
ProcessorAgent.WriteToMemory(sp, valueToPush.GetHighByte());
sp--;
ProcessorAgent.WriteToMemory(sp, valueToPush.GetLowByte());
Registers.SP = (short)sp;
Registers.PC = newAddress;
return(17);
}
/// <summary>
/// The DEC (HL) instruction.
/// </summary>
private byte DEC_aHL()
{
FetchFinished();
var address = Registers.HL.ToUShort();
var oldValue = ProcessorAgent.ReadFromMemory(address);
var newValue = oldValue.Dec();
ProcessorAgent.WriteToMemory(address, newValue);
Registers.SF = newValue.GetBit(7);
Registers.ZF = (newValue == 0);
Registers.HF = ((newValue & 0x0F) == 0x0F);
Registers.PF = (newValue == 0x7F);
Registers.NF = 1;
SetFlags3and5From(newValue);
return(11);
}
/// <summary>
/// The INC (HL) instruction.
/// </summary>
private byte INC_aHL()
{
FetchFinished();
var address = (ushort)Registers.HL;
var oldValue = ProcessorAgent.ReadFromMemory(address);
var newValue = (byte)(oldValue + 1);
ProcessorAgent.WriteToMemory(address, newValue);
Registers.SF = newValue.GetBit(7);
Registers.ZF = (newValue == 0);
Registers.HF = ((newValue & 0x0F) == 0x00);
Registers.PF = (newValue == 0x80);
Registers.NF = 0;
SetFlags3and5From(newValue);
return(11);
}
/// <summary>
/// The DEC (IY+n) instruction.
/// </summary>
private byte DEC_aIY_plus_n()
{
var offset = ProcessorAgent.FetchNextOpcode();
FetchFinished();
var address = Registers.IY.ToUShort().Add(offset.ToSignedByte());
var oldValue = ProcessorAgent.ReadFromMemory(address);
var newValue = oldValue.Dec();
ProcessorAgent.WriteToMemory(address, newValue);
Registers.SF = newValue.GetBit(7);
Registers.ZF = (newValue == 0);
Registers.HF = ((newValue & 0x0F) == 0x0F);
Registers.PF = (newValue == 0x7F);
Registers.NF = 1;
SetFlags3and5From(newValue);
return(23);
}
/// <summary>
/// The DEC (IY+n) instruction.
/// </summary>
private byte DEC_aIY_plus_n()
{
var offset = ProcessorAgent.FetchNextOpcode();
FetchFinished();
var address = (ushort)(Registers.IY + (SByte)offset);
var oldValue = ProcessorAgent.ReadFromMemory(address);
var newValue = (byte)(oldValue - 1);
ProcessorAgent.WriteToMemory(address, newValue);
Registers.SF = newValue.GetBit(7);
Registers.ZF = (newValue == 0);
Registers.HF = ((newValue & 0x0F) == 0x0F);
Registers.PF = (newValue == 0x7F);
Registers.NF = 1;
SetFlags3and5From(newValue);
return(23);
}
/// <summary>
/// The RLD instruction.
/// </summary>
byte RLD()
{
FetchFinished();
var memoryAddress = Registers.HL.ToUShort();
var Avalue = Registers.A;
var HLcontents = ProcessorAgent.ReadFromMemory(memoryAddress);
var newAvalue = (byte)((Avalue & 0xF0) | ((HLcontents >> 4) & 0x0F));
var newHLcontents = (byte)(((HLcontents << 4) & 0xF0) | (Avalue & 0x0F));
Registers.A = newAvalue;
ProcessorAgent.WriteToMemory(memoryAddress, newHLcontents);
Registers.SF = newAvalue.GetBit(7);
Registers.ZF = (newAvalue == 0);
Registers.HF = 0;
Registers.PF = Parity[newAvalue];
Registers.NF = 0;
SetFlags3and5From(newAvalue);
return(18);
}