private void Load(string[] operands)
{
if (operands.Length == 2)
{
if (RegisterSyntax.TryParse(operands[0], out var register) && AddressSyntax.TryParse(operands[1], _symbolTable, out var address))
{
_bytes.Add(((byte)Opcode.ImmediateLoad, register.Index).Combine(), _currentLineNumber);
_bytes.Add(address, _currentLineNumber);
return;
}
if (RegisterSyntax.TryParse(operands[0], out register) && AddressSyntax.TryParse(operands[1], _symbolTable, out address, BracketExpectation.Present))
{
_bytes.Add(((byte)Opcode.DirectLoad, register.Index).Combine(), _currentLineNumber);
_bytes.Add(address, _currentLineNumber);
return;
}
if (RegisterSyntax.TryParse(operands[0], out var register1) && RegisterSyntax.TryParse(operands[1], out var register2, BracketExpectation.Present))
{
_bytes.Add(((byte)Opcode.IndirectLoad, (byte)0x0).Combine(), _currentLineNumber);
_bytes.Add((register1.Index, register2.Index).Combine(), _currentLineNumber);
return;
}
}
throw new AssemblyException("Invalid operands for load instruction.", _currentLineNumber);
}
public static bool TryParse(string input, out RegisterSyntax registerSyntax, BracketExpectation bracketExpectation = BracketExpectation.NotPresent)
{
bool isSuccess;
bool isRegister = Regex.IsMatch(input, @"^\[?R[0-9A-F]\]?$");
bool isSurroundedByBrackets = input.StartsWith("[") && input.EndsWith("]");
if (bracketExpectation == BracketExpectation.Present)
{
isSuccess = isRegister && isSurroundedByBrackets;
}
else
{
isSuccess = isRegister && !isSurroundedByBrackets;
}
if (isSuccess)
{
registerSyntax = new RegisterSyntax(input.Trim('[', ']'));
}
else
{
registerSyntax = null;
}
return(isSuccess);
}
private void Xor(string[] operands)
{
if (operands.Length == 3)
{
if (RegisterSyntax.TryParse(operands[0], out var register1) && RegisterSyntax.TryParse(operands[1], out var register2) && RegisterSyntax.TryParse(operands[2], out var register3))
{
_bytes.Add(((byte)Opcode.Xor, register1.Index).Combine(), _currentLineNumber);
_bytes.Add((register2.Index, register3.Index).Combine(), _currentLineNumber);
return;
}
}
throw new AssemblyException("Invalid operands for xor instruction.", _currentLineNumber);
}
private void JmpLE(string[] operands)
{
if (operands.Length == 2)
{
if (RegisterSyntax.TryParse(operands[0].Split('<', '=')[0], out var register) && AddressSyntax.TryParse(operands[1], _symbolTable, out var address))
{
_bytes.Add(((byte)Opcode.JumpLessEqual, register.Index).Combine(), _currentLineNumber);
_bytes.Add(address, _currentLineNumber);
return;
}
}
throw new AssemblyException("Invalid operands for jmple instruction.", _currentLineNumber);
}
private void Ror(string[] operands)
{
if (operands.Length == 2)
{
if (RegisterSyntax.TryParse(operands[0], out var register) && NumberSyntax.TryParse(operands[1], out byte number))
{
if (number < 16)
{
_bytes.Add(((byte)Opcode.Ror, register.Index).Combine(), _currentLineNumber);
_bytes.Add(((byte)0x0, number).Combine(), _currentLineNumber);
return;
}
else
{
throw new AssemblyException("Number cannot be larger than 15.", _currentLineNumber);
}
}
}
throw new AssemblyException("Invalid operands for ror instruction.", _currentLineNumber);
}
private void JmpEQ(string[] operands)
{
if (operands.Length == 2)
{
string[] registers = operands[0].Split('=');
if (!RegisterSyntax.TryParse(registers[1], out var rightRegister) || rightRegister.Index != 0)
{
throw new AssemblyException("Expected a comparison with R0.", _currentLineNumber);
}
if (RegisterSyntax.TryParse(registers[0], out var leftRegister) && AddressSyntax.TryParse(operands[1], _symbolTable, out var address))
{
_bytes.Add(((byte)Opcode.JumpEqual, leftRegister.Index).Combine(), _currentLineNumber);
_bytes.Add(address, _currentLineNumber);
return;
}
}
throw new AssemblyException("Invalid operands for jmpeq instruction.", _currentLineNumber);
}