public static Operand Parse(string text)
{
//v=LABEL | ($ff | 255 | %10101010) | ($ffff | 64000 | %1010101010101010
//v
//[v]
//[[v]]
//[v,X]
//[[v,X]]
//[[v],X]
AddressingModes addressingMode = AddressingModes.Implied;
string parsed = text;
if (parsed != null)
{
bool isAddress = false;
bool isIndirect = false;
bool isIndexed = false;
bool isPreIndexed = false;
bool isPostIndexed = false;
if (parsed[0] == '[')
{
if (parsed[parsed.Length - 1] != ']')
{
throw new InvalidOperationException("can't parse {" + text + "}");
}
isAddress = true;
parsed = parsed.Substring(1, parsed.Length - 2);
if (parsed[0] == '[')
{
isIndirect = true;
if (parsed.Substring(parsed.Length - 3, 3) == ",X]")
{
isPreIndexed = true;
parsed = parsed.Substring(1, parsed.Length - 4);
}
else if (parsed.Substring(parsed.Length - 3, 3) == "],X")
{
isPostIndexed = true;
parsed = parsed.Substring(1, parsed.Length - 4);
}
else if (parsed[parsed.Length - 1] == ']')
{
parsed = parsed.Substring(1, parsed.Length - 2);
}
else
{
throw new InvalidOperationException("can't parse {" + text + "}");
}
}
if (parsed.Substring(parsed.Length - 2, 2) == ",X")
{
isIndexed = true;
parsed = parsed.Substring(0, parsed.Length - 2);
}
}
if (parsed.Length == 0)
{
throw new InvalidOperationException("can't parse {" + text + "}");
}
//parse label or literal
UInt ui = null;
string name = null;
if (char.IsLetter(parsed[0]) || parsed[0] == '_')
{
if (!parsed.All(c => char.IsLetterOrDigit(c) || c == '_'))
{
throw new InvalidOperationException("can't parse {" + text + "}");
}
name = parsed;
}
else
{
ui = UInt.Parse(parsed);
if (isAddress && ui is U8)
{
ui = new U16(((U8)ui).Read());
}
}
if (isAddress)
{
//address literal or pointer (label)
if (isIndirect)
{
if (isPreIndexed)
{
addressingMode = AddressingModes.IndirectPreIndexed;
}
else if (isPostIndexed)
{
addressingMode = AddressingModes.IndirectPostIndexed;
}
else
{
addressingMode = AddressingModes.Indirect;
}
}
else
{
if (isIndexed)
{
addressingMode = AddressingModes.Indexed;
}
else
{
addressingMode = AddressingModes.Absolute;
}
}
Value value = null;
if (ui != null)
{
value = new Literal(ui);
}
else
{
value = new Pointer(name);
}
return(new Operand(value, addressingMode));
}
else
{
//immediate literal or constant (label)
if (ui != null)
{
if (ui is U8)
{
addressingMode = AddressingModes.Immediate;
}
else if (ui is U16)
{
addressingMode = AddressingModes.BigImmediate;
}
else
{
throw new NotSupportedException("only U8 and U16 supported");
}
return(new Operand(new Literal(ui), addressingMode));
}
else
{
//how to tell if a constant label is 8 or 16?
//TODO: look up .EQU in symbol table
return(new Operand(new Constant(name, null), addressingMode));
}
}
}
else
{
//implied
return(new Operand());
}
}
public static Operand Parse(string text)
{
//v=LABEL | ($ff | 255 | %10101010) | ($ffff | 64000 | %1010101010101010
//v
//[v]
//[[v]]
//[v,X]
//[[v,X]]
//[[v],X]
AddressingModes addressingMode = AddressingModes.Implied;
string parsed = text;
if (parsed != null)
{
bool isAddress = false;
bool isIndirect = false;
bool isIndexed = false;
bool isPreIndexed = false;
bool isPostIndexed = false;
if (parsed[0] == '[')
{
if (parsed[parsed.Length - 1] != ']') throw new InvalidOperationException("can't parse {" + text + "}");
isAddress = true;
parsed = parsed.Substring(1, parsed.Length - 2);
if (parsed[0] == '[')
{
isIndirect = true;
if (parsed.Substring(parsed.Length - 3, 3) == ",X]")
{
isPreIndexed = true;
parsed = parsed.Substring(1, parsed.Length - 4);
}
else if (parsed.Substring(parsed.Length - 3, 3) == "],X")
{
isPostIndexed = true;
parsed = parsed.Substring(1, parsed.Length - 4);
}
else if (parsed[parsed.Length - 1] == ']')
{
parsed = parsed.Substring(1, parsed.Length - 2);
}
else
{
throw new InvalidOperationException("can't parse {" + text + "}");
}
}
if (parsed.Substring(parsed.Length - 2, 2) == ",X")
{
isIndexed = true;
parsed = parsed.Substring(0, parsed.Length - 2);
}
}
if (parsed.Length == 0) throw new InvalidOperationException("can't parse {" + text + "}");
//parse label or literal
UInt ui = null;
string name = null;
if (char.IsLetter(parsed[0])||parsed[0]=='_')
{
if (!parsed.All(c => char.IsLetterOrDigit(c) || c=='_')) throw new InvalidOperationException("can't parse {" + text + "}");
name = parsed;
}
else
{
ui = UInt.Parse(parsed);
if (isAddress && ui is U8)
{
ui = new U16(((U8)ui).Read());
}
}
if (isAddress)
{
//address literal or pointer (label)
if (isIndirect)
{
if (isPreIndexed) addressingMode = AddressingModes.IndirectPreIndexed;
else if (isPostIndexed) addressingMode = AddressingModes.IndirectPostIndexed;
else addressingMode = AddressingModes.Indirect;
}
else
{
if (isIndexed)
{
addressingMode = AddressingModes.Indexed;
}
else
{
addressingMode = AddressingModes.Absolute;
}
}
Value value = null;
if (ui!=null)
{
value = new Literal(ui);
}
else
{
value=new Pointer(name);
}
return new Operand(value, addressingMode);
}
else
{
//immediate literal or constant (label)
if (ui!=null)
{
if (ui is U8)
{
addressingMode = AddressingModes.Immediate;
}
else if (ui is U16)
{
addressingMode = AddressingModes.BigImmediate;
}
else
{
throw new NotSupportedException("only U8 and U16 supported");
}
return new Operand(new Literal(ui), addressingMode);
}
else
{
//how to tell if a constant label is 8 or 16?
//TODO: look up .EQU in symbol table
return new Operand(new Constant(name,null), addressingMode);
}
}
}
else
{
//implied
return new Operand();
}
}