/// <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 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 IN A,(n) instruction.
/// </summary>
byte IN_A_n()
{
var portNumber = ProcessorAgent.FetchNextOpcode();
FetchFinished();
Registers.A = ProcessorAgent.ReadFromPort(portNumber);
return(11);
}
/// <summary>
/// The IN F,(C) instruction.
/// </summary>
byte IN_F_C()
{
FetchFinished();
var value = ProcessorAgent.ReadFromPort(Registers.C);
Registers.SF = value.GetBit(7);
Registers.ZF = (value == 0);
Registers.NF = 0;
Registers.HF = 0;
Registers.PF = Parity[value];
SetFlags3and5From(value);
return(12);
}