// decodes a parameter and adds it to bytecode stream.
// return either DataElement, int, double, or String (for type checking)
private Object DecodeAndAddParameter(DataArea locals, String p)
{
// this must be a label address difference
if ((!p.StartsWith("'")) && p.Contains(':'))
{
currentobject.AddLabelDifference(p);
return(999999999); // only compatible with 32bit numbers
}
// this must be a variable
else if ((p[0] >= 'A' && p[0] <= 'Z') || p[0] == '_')
{
// check if have offset suffix
int offset = 0;
int plusidx = p.IndexOf('+');
if (plusidx >= 0)
{
if (Int32.TryParse(p.Substring(plusidx + 1), NumberStyles.Integer, CultureInfo.InvariantCulture, out offset))
{
p = p.Substring(0, plusidx);
}
}
DataElement e = null;
bool local = true;
if (locals != null)
{
e = locals.Get(p);
}
if (e == null)
{
e = globals.Get(p);
local = false;
}
if (e == null)
{
throw new AssemblerException("Unknown identifier " + p);
}
currentobject.AddVariableReference(e.position + offset, local);
return(e);
}
// this must be a constant numeric value
else if ((p[0] >= '0' && p[0] <= '9') || p[0] == '-')
{
Int32 c;
double d;
if (Int32.TryParse(p, NumberStyles.Integer, CultureInfo.InvariantCulture, out c))
{
currentobject.AddConstant(c);
return(c);
}
if (double.TryParse(p, NumberStyles.Float, CultureInfo.InvariantCulture, out d))
{
currentobject.AddFloatConstant(d);
return(d);
}
throw new AssemblerException("Can not decode number: " + p);
}
// this must be a string literal
else if (p[0] == '\'')
{
String l = p.Substring(1, p.Length - 2);
currentobject.AddStringLiteral(l);
return(l);
}
else
{
throw new AssemblerException("Invalid parameter value");
}
}