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 void Assemble(string[] lines, IOutput output)
{
Beboputer.Bebop.Reset();
bool errors = false;
for (int i = 0; i < lines.Length; ++i)
{
//FOO: .EQU $FF # this is a comment
//FOO: .BYTE $FF,$FF,$FF # this is a comment
//FOO: LDA $FF # this is a comment
//{LABEL} {DIR|INS} {UINT|OPERAND} {COMMENT}
try
{
string[] parts = lines[i].Split((char[])null, StringSplitOptions.RemoveEmptyEntries);
int p = 0;
string label = null;
string comment = null;
Line line = null;
if (parts.Length > 0 && parts[0].Length > 0)
{
//label
if (char.IsLetter(parts[p][0]) || parts[p][0] == '_')
{
if (parts[p][parts[p].Length - 1] == ':')
{
label = parts[p].Substring(0, parts[p].Length - 1);
++p;
}
}
if (parts[p][0] == '.') //directive
{
if (parts[p].Length == 1)
{
throw new InvalidOperationException("can't parse line " + i + " {" + lines[i] + "}");
}
string dir = parts[p].Substring(1, parts[p].Length - 1);
if (Beboputer.Directives.ContainsKey(dir))
{
++p;
string parm = null;
if (p < parts.Length)
{
if (parts[p][0] != '#')
{
parm = parts[p];
++p;
}
}
Directive directive = (Directive)Activator.CreateInstance(Beboputer.Directives[dir]);
if (parm != null)
{
directive.Value = UInt.Parse(parm);
}
line = directive;
}
else
{
throw new InvalidOperationException("unknown directive line " + i + " {" + lines[i] + "}");
}
}
else if (Beboputer.Instructions.ContainsKey(parts[p])) //instruction
{
string ins = parts[p];
++p;
string parm = null;
if (p < parts.Length)
{
if (parts[p][0] != '#')
{
parm = parts[p];
++p;
}
}
Instruction instruction = (Instruction)Activator.CreateInstance(Beboputer.Instructions[ins]);
if (parm != null)
{
instruction.Operand = Operand.Parse(parm);
}
line = instruction;
}
else if (parts[p][0] == '#') //comment only line
{
//this is okay
}
else
{
throw new InvalidOperationException("unknown instruction line " + i + " {" + lines[i] + "}");
}
if (p < parts.Length)
{
if (parts[p][0] == '#')
{
parts[p] = parts[p].Substring(1, parts[p].Length - 1);
comment = "";
for (int j = p; j < (parts.Length); ++j)
{
if (comment != "")
{
comment += " ";
}
comment += parts[j];
}
}
else
{
throw new InvalidOperationException("unknown syntax line " + i + " {" + lines[i] + "}");
}
}
}
if (line == null)
{
if (comment != null)
{
line = new Comment();
}
else
{
if (lines[i].Trim().Length != 0)
{
throw new InvalidOperationException("can't parse line " + i + " {" + lines[i] + "}");
}
line = new Line();
}
}
line.Text = lines[i];
if (line is Statement)
{
((Statement)line).Label = label;
((Statement)line).Comment = comment;
if (label != null)
{
if (Beboputer.Bebop.Labels.ContainsKey(label))
{
throw new InvalidOperationException("label {" + label + "} already exists line " + i + " {" + lines[i] + "}");
}
Beboputer.Bebop.Labels.Add(label, (Statement)line);
}
}
else
{
if (label != null)
{
throw new InvalidOperationException("label invalid for line " + i + " {" + lines[i] + "}");
}
}
Beboputer.Bebop.Lines.Add(line);
output.Out(i + ":\t" + line.ToString());
}
catch (Exception ex)
{
errors = true;
output.Out("ERROR: " + i + ":\t" + ex.Message);
}
}
//load
ushort address = 0;
foreach (Line line in Beboputer.Bebop.Lines)
{
if (line is ORG)
{
address = ((U16)((ORG)line).Value).Read();
}
else if (line is Instruction)
{
Instruction ins = (Instruction)line;
byte opcode;
if (Beboputer.Opcodes.ContainsKey(Instruction.GetOpcodeKey(ins.Mnemonic, ins.AddressingMode)))
{
opcode = Beboputer.Opcodes[Instruction.GetOpcodeKey(ins.Mnemonic, ins.AddressingMode)];
}
else
{
throw new InvalidOperationException("no opcode for {" + ins.ToString() + "}");
}
Beboputer.Bebop.RAM.Write(address, opcode);
++address;
if (ins.Operand != null)
{
if (ins.Operand.Value is Literal)
{
Literal l = (Literal)ins.Operand.Value;
if (l.Value is U8)
{
Beboputer.Bebop.RAM.Write(address, ((U8)l.Value).Read());
++address;
}
else if (l.Value is U16)
{
ushort v = ((U16)l.Value).Read();
Beboputer.Bebop.RAM.Write(address, (byte)((v & 0xFF00) >> 8));
++address;
Beboputer.Bebop.RAM.Write(address, (byte)(v & 0xFF));
++address;
}
}
else
{
throw new NotImplementedException("not yet");
}
}
}
}
//refresh windows
Beboputer.Bebop.Load();
}