public override Tlcs90Instruction Decode(uint bPrev, Tlcs90Disassembler dasm)
{
Tlcs90Instruction instr;
Constant offset = null;
RegisterStorage baseReg = null;
RegisterStorage idxReg = null;
switch (format[0])
{
case 'E':
switch (format[1])
{
case 'S': baseReg = Registers.sp; break;
case 'X': baseReg = Registers.ix; break;
case 'Y': baseReg = Registers.iy; break;
case 'H': baseReg = Registers.hl; idxReg = Registers.a; break;
default: throw new NotImplementedException(string.Format("Tlcs-90: src {0}", format));
}
;
if (idxReg == null)
{
if (!dasm.rdr.TryReadByte(out byte bOff))
{
return(null);
}
offset = Constant.SByte((sbyte)bOff);
}
break;
case 'B': baseReg = Registers.bc; break;
case 'D': baseReg = Registers.de; break;
case 'H': baseReg = Registers.hl; break;
case 'S': baseReg = Registers.sp; break;
case 'X': baseReg = Registers.ix; break;
case 'Y': baseReg = Registers.iy; break;
case 'M':
ushort us;
if (!dasm.rdr.TryReadLeUInt16(out us))
{
return(null);
}
offset = Constant.UInt16(us);
break;
case 'm':
byte pageAddr;
if (!dasm.rdr.TryReadByte(out pageAddr))
{
return(null);
}
offset = Constant.UInt16((ushort)(0xFF00 | pageAddr));
break;
default: throw new NotImplementedException(string.Format("Tlcs-90: src {0}", format));
}
if (!dasm.rdr.TryReadByte(out byte b))
{
return(null);
}
instr = srcEncodings[b].Decode(b, dasm);
if (instr == null)
{
return(null);
}
var operand = new MemoryOperand(dasm.dataWidth)
{
Base = baseReg,
Index = idxReg,
Offset = offset
};
if (dasm.backPatchOp == 0)
{
if (instr.Operands.Length == 1)
{
instr.Operands = new MachineOperand[] { operand, instr.Operands[0] };
}
else
{
instr.Operands = new MachineOperand[] { operand };
}
if (instr.Operands.Length >= 2)
{
operand.Width = instr.Operands[1].Width;
}
}
else if (dasm.backPatchOp == 1)
{
if (operand != null)
{
instr.Operands = new MachineOperand[] { instr.Operands[0], operand };
}
operand.Width = instr.Operands[0].Width;
}
else
{
return(null);
}
return(instr);
}
private Tlcs90Instruction DecodeOperands(byte b, Opcode opcode, string format)
{
int op = 0;
var ops = new MachineOperand[2];
Constant c;
PrimitiveType size;
for (int i = 0; i < format.Length; ++i)
{
switch (format[i])
{
case ',':
continue;
case 'a':
this.dataWidth = PrimitiveType.Byte;
ops[op] = new RegisterOperand(Registers.a);
break;
case '@':
this.dataWidth = PrimitiveType.Word16;
ops[op] = new RegisterOperand(Registers.af_);
break;
case 'A':
this.dataWidth = PrimitiveType.Word16;
ops[op] = new RegisterOperand(Registers.af);
break;
case 'B':
this.dataWidth = PrimitiveType.Word16;
ops[op] = new RegisterOperand(Registers.bc);
break;
case 'c':
ops[op] = new ConditionOperand((CondCode)(b & 0xF));
break;
case 'D':
this.dataWidth = PrimitiveType.Word16;
ops[op] = new RegisterOperand(Registers.de);
break;
case 'I':
// Immediate value
this.dataWidth = GetSize(format[++i]);
if (!rdr.TryReadLe(this.dataWidth, out c))
{
return(null);
}
ops[op] = new ImmediateOperand(c);
break;
case 'i': // immediate value from opcode bits
ops[op] = ImmediateOperand.Byte((byte)(b & 0x7));
break;
case 'g':
Debug.Assert(byteReg != null);
ops[op] = this.byteReg;
break;
case 'G':
Debug.Assert(wordReg != null);
ops[op] = this.wordReg;
break;
case 'H':
ops[op] = new RegisterOperand(Registers.hl);
break;
case 'J':
// Absolute jump.
size = GetSize(format[++i]);
if (!rdr.TryReadLe(size, out c))
{
return(null);
}
ops[op] = AddressOperand.Ptr16(c.ToUInt16());
break;
case 'j':
// relative jump
size = GetSize(format[++i]);
Address dest;
if (size.Size == 1)
{
if (!rdr.TryReadByte(out b))
{
return(null);
}
dest = rdr.Address + (sbyte)b;
}
else
{
if (!rdr.TryReadLeInt16(out short off))
{
return(null);
}
dest = rdr.Address + off;
}
ops[op] = AddressOperand.Create(dest);
break;
case 'M':
this.dataWidth = GetSize(format[++i]);
ushort absAddr;
if (!rdr.TryReadLeUInt16(out absAddr))
{
return(null);
}
ops[op] = MemoryOperand.Absolute(this.dataWidth, absAddr);
break;
case 'm':
size = GetSize(format[++i]);
byte pageAddr;
if (!rdr.TryReadByte(out pageAddr))
{
return(null);
}
ops[op] = MemoryOperand.Absolute(size, (ushort)(0xFF00 | pageAddr));
break;
case 'S':
this.dataWidth = PrimitiveType.Word16;
ops[op] = new RegisterOperand(Registers.sp);
break;
case 'X':
this.dataWidth = PrimitiveType.Word16;
ops[op] = new RegisterOperand(Registers.ix);
break;
case 'Y':
this.dataWidth = PrimitiveType.Word16;
ops[op] = new RegisterOperand(Registers.iy);
break;
case 'r':
// Register encoded in low 3 bits of b.
ops[op] = new RegisterOperand(Registers.byteRegs[b & 7]);
dataWidth = PrimitiveType.Byte;
break;
case 'x':
this.backPatchOp = op;
break;
default: throw new NotImplementedException(string.Format("Encoding '{0}' not implemented yet.", format[i]));
}
++op;
}
return(new Tlcs90Instruction
{
Opcode = opcode,
op1 = op > 0 ? ops[0] : null,
op2 = op > 1 ? ops[1] : null,
});
}
public override Tlcs90Instruction Decode(uint bPrev, Tlcs90Disassembler dasm)
{
RegisterStorage baseReg = null;
RegisterStorage idxReg = null;
ushort? absAddr = null;
Constant offset = null;
switch (format[0])
{
case 'M':
ushort a;
if (!dasm.rdr.TryReadLeUInt16(out a))
{
return(null);
}
absAddr = a;
break;
case 'm':
byte bb;
if (!dasm.rdr.TryReadByte(out bb))
{
return(null);
}
absAddr = (ushort)(0xFF00 | bb);
break;
case 'B': baseReg = Registers.bc; break;
case 'D': baseReg = Registers.de; break;
case 'H': baseReg = Registers.hl; break;
case 'X': baseReg = Registers.ix; break;
case 'Y': baseReg = Registers.iy; break;
case 'S': baseReg = Registers.sp; break;
case 'E':
switch (format[1])
{
case 'S': baseReg = Registers.sp; break;
case 'X': baseReg = Registers.ix; break;
case 'Y': baseReg = Registers.ix; break;
case 'H': baseReg = Registers.hl; idxReg = Registers.a; break;
default: throw new NotImplementedException(string.Format("Tlcs-90: dst {0}", format));
}
if (idxReg == null)
{
if (!dasm.rdr.TryReadByte(out byte bOff))
{
return(null);
}
offset = Constant.SByte((sbyte)bOff);
}
break;
default: throw new NotImplementedException(string.Format("Tlcs-90: dst {0}", format));
}
if (!dasm.rdr.TryReadByte(out byte b))
{
return(null);
}
var instr = dstEncodings[b].Decode(b, dasm);
if (instr == null)
{
return(null);
}
var operand = new MemoryOperand(dasm.dataWidth)
{
Base = baseReg,
Offset = absAddr.HasValue
? Constant.UInt16(absAddr.Value)
: offset,
};
if (dasm.backPatchOp == 0)
{
if (instr.Operands.Length == 0)
{
instr.Operands = new MachineOperand[] { operand };
}
else
{
instr.Operands = new MachineOperand[] { operand, instr.Operands[0] };
}
if (instr.Operands.Length == 2)
{
instr.Operands[0].Width = instr.Operands[1].Width;
}
}
else if (dasm.backPatchOp == 1)
{
if ((instr.Mnemonic == Mnemonic.jp || instr.Mnemonic == Mnemonic.call)
&&
operand.Base == null &&
operand.Index == null &&
operand.Offset != null)
{
// JP cc,(XXXX) should be JP cc,XXXX
var op = AddressOperand.Ptr16(operand.Offset.ToUInt16());
op.Width = PrimitiveType.Ptr16;
instr.Operands = new MachineOperand[] { instr.Operands[0], op };
}
else
{
instr.Operands = new MachineOperand[] {
instr.Operands[0],
operand
};
instr.Operands[1].Width = instr.Operands[0].Width;
}
}
else
{
return(null);
}
return(instr);
}
public override Tlcs90Instruction Decode(byte b, Tlcs90Disassembler dasm)
{
RegisterStorage baseReg = null;
RegisterStorage idxReg = null;
ushort? absAddr = null;
Constant offset = null;
switch (format[0])
{
case 'M':
ushort a;
if (!dasm.rdr.TryReadLeUInt16(out a))
{
return(null);
}
absAddr = a;
break;
case 'm':
byte bb;
if (!dasm.rdr.TryReadByte(out bb))
{
return(null);
}
absAddr = (ushort)(0xFF00 | bb);
break;
case 'B': baseReg = Registers.bc; break;
case 'D': baseReg = Registers.de; break;
case 'H': baseReg = Registers.hl; break;
case 'X': baseReg = Registers.ix; break;
case 'Y': baseReg = Registers.iy; break;
case 'S': baseReg = Registers.sp; break;
case 'E':
switch (format[1])
{
case 'S': baseReg = Registers.sp; break;
case 'X': baseReg = Registers.ix; break;
case 'Y': baseReg = Registers.ix; break;
case 'H': baseReg = Registers.hl; idxReg = Registers.a; break;
default: throw new NotImplementedException(string.Format("Tlcs-90: dst {0}", format));
}
if (idxReg == null)
{
if (!dasm.rdr.TryReadByte(out b))
{
return(null);
}
offset = Constant.SByte((sbyte)b);
}
break;
default: throw new NotImplementedException(string.Format("Tlcs-90: dst {0}", format));
}
if (!dasm.rdr.TryReadByte(out b))
{
return(null);
}
var instr = dstEncodings[b].Decode(b, dasm);
if (instr == null)
{
return(null);
}
var operand = new MemoryOperand(dasm.dataWidth)
{
Base = baseReg,
Offset = absAddr.HasValue
? Constant.UInt16(absAddr.Value)
: offset,
};
if (dasm.backPatchOp == 0)
{
instr.op1 = operand;
if (instr.op2 != null)
{
instr.op1.Width = instr.op2.Width;
}
}
else if (dasm.backPatchOp == 1)
{
instr.op2 = operand;
instr.op2.Width = instr.op1.Width;
}
else
{
return(null);
}
return(instr);
}
