public override M6809Instruction Decode(uint wInstr, M6809Disassembler dasm)
{
if (!dasm.rdr.TryReadByte(out byte opcode))
{
return(dasm.CreateInvalidInstruction());
}
return(subDecoders[opcode].Decode(opcode, dasm));
}
private static bool Iw(uint wInstr, M6809Disassembler dasm)
{
if (!dasm.rdr.TryReadBeUInt16(out ushort u))
{
return(false);
}
dasm.ops.Add(ImmediateOperand.Word16(u));
return(true);
}
private static bool Ib(uint wInstr, M6809Disassembler dasm)
{
if (!dasm.rdr.TryReadByte(out byte b))
{
return(false);
}
dasm.ops.Add(ImmediateOperand.Byte(b));
return(true);
}
private static bool PCw(uint wInstr, M6809Disassembler dasm)
{
if (!dasm.rdr.TryReadBeInt16(out short d))
{
return(false);
}
var addr = dasm.rdr.Address + d;
dasm.ops.Add(AddressOperand.Create(addr));
return(true);
}
private static bool PCb(uint wInstr, M6809Disassembler dasm)
{
if (!dasm.rdr.TryReadByte(out byte b))
{
return(false);
}
var addr = dasm.rdr.Address + (sbyte)b;
dasm.ops.Add(AddressOperand.Create(addr));
return(true);
}
private static bool Exg(uint wInstr, M6809Disassembler dasm)
{
if (!dasm.rdr.TryReadByte(out byte b))
{
return(false);
}
var r0 = exgRegs[(uint)b >> 4];
var r1 = exgRegs[b & 0xF];
if (r0 == null || r1 == null)
{
return(false);
}
dasm.ops.Add(new RegisterOperand(r0));
dasm.ops.Add(new RegisterOperand(r1));
return(true);
}
public override M6809Instruction Decode(uint wInstr, M6809Disassembler dasm)
{
foreach (var m in mutators)
{
if (!m(wInstr, dasm))
{
return(dasm.CreateInvalidInstruction());
}
}
var instr = new M6809Instruction
{
InstructionClass = iclass,
Mnemonic = mnemonic,
Operands = dasm.ops.ToArray()
};
return(instr);
}
private static bool B(uint wInstr, M6809Disassembler dasm)
{
dasm.ops.Add(new RegisterOperand(Registers.B));
return(true);
}