private Z80CPU.Op DecodeOp(State state)
{
while (true)
{
var b = z80.Memory.ReadByte(state.Address++);
switch (b)
{
case 0xDD:
manipulateDecoded = input => input.Replace("(HL)", "(IXx)").Replace("HL", "IX");
state.IndexerRegister = Z80CPU.IndexerRegister.IX;
continue;
case 0xFD:
manipulateDecoded = input => input.Replace("(HL)", "(IYx)").Replace("HL", "IY");
state.IndexerRegister = Z80CPU.IndexerRegister.IY;
continue;
case 0xCB:
if (state.IndexerRegister != Z80CPU.IndexerRegister.HL)
state.IndexerOffset = (SByte) z80.Memory.ReadByte(state.Address++);
return z80.opCB[z80.Memory.ReadByte(state.Address++)];
case 0xED:
return z80.opED[z80.Memory.ReadByte(state.Address++)];
default:
return z80.op[b];
}
}
}
private String DecodeText(State state, Z80CPU.Op op)
{
if (op == null)
return String.Format("DEFB " + HexByte, z80.Memory.ReadByte(state.Address));
var text = op.Name;
if (manipulateDecoded != null)
{
text = manipulateDecoded.Invoke(text);
manipulateDecoded = null;
}
if (text.Contains("x"))
{
var x = state.IndexerOffset ?? (SByte)z80.Memory.ReadByte(state.Address++);
text = text.Replace("x", x.ToString("+;-;") + String.Format(HexByte, x));
}
if (text.Contains("e"))
{
var e = (SByte)(z80.Memory.ReadByte(state.Address++));
text = text.Replace("e", "$" + new LEWord((UInt16)(state.Address + e)));
// + " (" + e.ToString("+0;-0;0") + ")");
}
if (text.Contains("nn"))
{
var nn = z80.Memory.ReadWord(state.Address);
state.Address += 2;
text = text.Replace("nn", String.Format(HexWord, nn));
}
if (text.Contains("n"))
{
var n = z80.Memory.ReadByte(state.Address++);
text = text.Replace("n", String.Format(HexByte, n));
}
return text;
}