Parse_Mem_Operand(string token, bool isCapitals = false)
{
int length = token.Length;
if (length < 3)
{
return(Valid : false, BaseReg : Rn.NOREG, IndexReg : Rn.NOREG, Scale : 0, Displacement : 0, NBits : 0, ErrorMessage : null); // do not return a error message because the provided token can be a label
}
if (!isCapitals)
{
token = token.ToUpper();
}
// 1] select everything between []
int beginPos = length;
for (int i = 0; i < length; ++i)
{
if (token[i] == '[')
{
beginPos = i + 1;
}
}
int endPos = length;
for (int i = beginPos; i < length; ++i)
{
if (token[i] == ']')
{
endPos = i;
}
}
int nBits = Get_Nbits_Mem_Operand(token);
token = token.Substring(beginPos, endPos - beginPos).Trim();
length = token.Length;
if (length == 0)
{
return(Valid : false, BaseReg : Rn.NOREG, IndexReg : Rn.NOREG, Scale : 0, Displacement : 0, NBits : 0, ErrorMessage : null);// do not return a error message because the provided token can be a label
}
// 2] check if the displacement is negative
bool negativeDisplacement = token.Contains('-');
if (negativeDisplacement)
{
token = token.Replace('-', '+');
}
// 3] remove superfluous initial +
if (token[0] == '+')
{
token = token.Substring(1, length - 1).Trim();
}
// 4] split based on +
string[] x = token.Split('+');
Rn baseRn = Rn.NOREG;
Rn indexRn = Rn.NOREG;
int scale = 0;
long displacement = 0;
bool foundDisplacement = false;
for (int i = 0; i < x.Length; ++i)
{
string y = x[i].Trim();
var(Valid, Value, NBits) = ExpressionEvaluator.Parse_Constant(y, true);
if (Valid)
{
if (foundDisplacement)
{
// found an second displacement, error
return(Valid : false, BaseReg : Rn.NOREG, IndexReg : Rn.NOREG, Scale : 0, Displacement : 0, NBits : 0, ErrorMessage : "Multiple displacements");
}
else
{
foundDisplacement = true;
displacement = (negativeDisplacement) ? -(long)Value : (long)Value;
}
}
else
{
Rn t1 = RegisterTools.ParseRn(y, true);
if (t1 != Rn.NOREG)
{
if (baseRn == Rn.NOREG)
{
baseRn = t1;
}
else
{
indexRn = t1;
scale = 1;
}
}
if (y.Contains('*'))
{
string[] z = y.Split('*');
string z0 = z[0].Trim();
string z1 = z[1].Trim();
string scaleRaw = null;
Rn z0r = RegisterTools.ParseRn(z0, true);
if (z0r != Rn.NOREG)
{
indexRn = z0r;
scaleRaw = z1;
scale = ParseScale(z1);
}
else
{
Rn z1r = RegisterTools.ParseRn(z1, true);
if (z1r != Rn.NOREG)
{
indexRn = z1r;
scaleRaw = z0;
scale = ParseScale(z0);
}
}
if (scale == -1)
{
return(Valid : false, BaseReg : Rn.NOREG, IndexReg : Rn.NOREG, Scale : 0, Displacement : 0, NBits : 0, ErrorMessage : "Invalid scale " + scaleRaw);
}
}
}
}
if ((baseRn != Rn.NOREG) && (indexRn != Rn.NOREG))
{
if (RegisterTools.NBits(baseRn) != RegisterTools.NBits(indexRn))
{
return(Valid : false, BaseReg : Rn.NOREG, IndexReg : Rn.NOREG, Scale : 0, Displacement : 0, NBits : 0, ErrorMessage : "Number of bits of base register " + baseRn + " is not equal to number of bits of index register " + indexRn);
}
}
return(Valid : true, BaseReg : baseRn, IndexReg : indexRn, Scale : scale, Displacement : displacement, NBits : nBits, ErrorMessage : null);
#region Local Methods
int ParseScale(string str)
{
switch (str)
{
case "1": return(1);
case "2": return(2);
case "4": return(4);
case "8": return(8);
default: return(-1);
}
}
/// <summary> Return the number of bits of the provided operand (assumes 64-bits) </summary>
int Get_Nbits_Mem_Operand(string token2)
{
string s = token2.TrimStart();
if (s.StartsWith("PTR"))
{
s = s.Substring(3, token.Length - 3).TrimStart();
}
if (s.StartsWith("BYTE"))
{
return(8); //nasm
}
if (s.StartsWith("SBYTE"))
{
return(8);
}
if (s.StartsWith("WORD"))
{
return(16); //nasm
}
if (s.StartsWith("SWORD"))
{
return(16);
}
if (s.StartsWith("DWORD"))
{
return(32); //nasm
}
if (s.StartsWith("SDWORD"))
{
return(32);
}
if (s.StartsWith("QWORD"))
{
return(64); //nasm
}
if (s.StartsWith("TWORD"))
{
return(80); //nasm
}
if (s.StartsWith("DQWORD"))
{
return(128);
}
if (s.StartsWith("OWORD"))
{
return(128); //nasm
}
if (s.StartsWith("XMMWORD"))
{
return(128);
}
if (s.StartsWith("XWORD"))
{
return(128);
}
if (s.StartsWith("YMMWORD"))
{
return(256);
}
if (s.StartsWith("YWORD"))
{
return(256); //nasm
}
if (s.StartsWith("ZMMWORD"))
{
return(512);
}
if (s.StartsWith("ZWORD"))
{
return(512); //nasm
}
//Console.WriteLine("AsmSourceTools:GetNbitsMemOperand: could not determine nBits in token " + token + " assuming 32 bits");
return(32);
}
#endregion
}
/// <summary> Check if the provided string is a constant by parsing it. Does not evaluate arithmetic in the string.</summary>
public static (bool Valid, ulong Value, int NBits) Parse_Constant(string token, bool isCapitals = false)
{
return(ExpressionEvaluator.Parse_Constant(token, isCapitals));
}