//Extract adress according to register offset specification
int DecodeRegisterOffset()
{
char Rm = (char)ExtractBits(code, 0, 3);
char Sh = (char)ExtractBits(code, 5, 6);
int shiftVal = ExtractBits(code, 7, 11);
shiftVal *= U ? 1 : -1;
stringValue = ", " + (shiftVal == 0 ? (U ? "" : "-") : "") + "r" + (int)Rm;
int regval = Regs.ReadWord(GetReg(Rm));
if (Rm == 15)
{
regval += 8;
}
if (shiftVal != 0)
{
stringValue += ", " + BarrelShifter.CodeToString(Sh) + " #" + shiftVal;
}
else if (!U)
{
regval *= -1;
}
return(BarrelShifter.ShiftByCode(regval, shiftVal, Sh));
}
//Calcultes and returns the immediate shift operand
int CalulateImmediateValue()
{
short shift = Convert.ToInt16(ExtractBits(code, 8, 11));
shift *= 2;
int immediate = ExtractBits(code, 0, 7);
immediate = BarrelShifter.ShiftByCode(immediate, shift, (char)3);
strVal = "#" + immediate;
return(immediate);
}
//Calcultes and returns the register shift operand
int CalculateRegisterOperand3()
{
int shiftVal;
Rm = (char)ExtractBits(code, 0, 3);
char Sh = (char)ExtractBits(code, 5, 6);
bool bit4 = TestFlag(code, 4);
char Rs = '0';
strShift = "r" + (int)Rm;
if (!bit4)
{
shiftVal = ExtractBits(code, 7, 11);
}
else
{
Rs = (char)ExtractBits(code, 8, 11);
shiftVal = Regs.ReadWord(GetReg(Rs));
if (Rs == 15)
{
shiftVal += 8;
}
}
if (shiftVal != 0)
{
strShift += ", " + BarrelShifter.CodeToString(Sh) + (bit4 ? " r" + (int)Rs : " #" + shiftVal);
}
int val = Regs.ReadWord(GetReg(Rm));
if (Rm == 15)
{
val += 8;
}
return(BarrelShifter.ShiftByCode(val, shiftVal, Sh));
}