protected void AssertTokenExist(Token token)
{
if (token == null)
{
var last = _stream.Last();
// Next char position
var start = last.Position.Start.ToTuple();
var end = last.Position.End.ToTuple();
start.Item2 += 1;
end.Item2 += 1;
var prettyPos = new Position(start, end);
throw SyntaxError.Make(SyntaxErrorMessages.UNEXPECTED_EOS(), prettyPos);
}
}
private AssemblyOperation ParseAssemblyOperation()
{
var asterisk = NextToken(false);
if (asterisk.IsOperator(Operator.Asterisk))
{
_stream.Next();
}
else
{
asterisk = null;
}
var reg = ParseRegister();
var allowedOps = new HashSet <string>()
{
Operator.Assign,
Operator.AssignPlus,
Operator.AssignMinus,
Operator.AssignShiftRight,
Operator.AssignShiftLeft,
Operator.AssignOr,
Operator.AssignAnd,
Operator.AssignXor,
Operator.AssignLess,
Operator.AssignGreater,
Operator.AssignCond
};
var op = NextToken();
if (op.Type != TokenType.Operator || !allowedOps.Contains(op.Value))
{
throw SyntaxError.Make(SyntaxErrorMessages.INVALID_TOKEN, op);
}
var node = new AssemblyOperation(op);
if (asterisk != null)
{
var deref = new Dereference(asterisk);
deref.AddChild(reg);
node.AddChild(deref);
}
else
{
node.AddChild(reg);
asterisk = NextToken(false);
if (asterisk.IsOperator(Operator.Asterisk))
{
_stream.Next();
}
else
{
asterisk = null;
}
}
// If we have two dereferences in the statement ParseRegister will fail
reg = ParseRegister();
if (asterisk != null)
{
var deref = new Dereference(asterisk);
deref.AddChild(reg);
node.AddChild(deref);
}
else
{
node.AddChild(reg);
}
if (!op.IsOperator(Operator.Assign) && asterisk != null)
{
throw SyntaxError.Make(SyntaxErrorMessages.INVALID_ASM_DEREFERENCE_USE(), node.Position);
}
return(node);
}
