private void DecodeBTypeInstruction(Instruction i, string[] immediate, int currentInstructionNumber)
{
BTypeInstruction b = (BTypeInstruction)i;
bool containsLabel = DetermineIfContainsLabel(0, immediate[0]);
if (containsLabel)
{
int immed = 0;
labels.TryGetValue(immediate[0], out immed);
b.immediateValue = immed - currentInstructionNumber - 1;
}
else
{
b.immediateValue = DetermineRegistersUsed(immediate, b.instructionSubType)[0] - 1;
}
}
// Sets the conditional bits
private void SetConditional(Instruction i, Conditional cond)
{
switch (i.instructionType)
{
case InstructionType.RType:
RTypeInstruction r = (RTypeInstruction)i;
r.cond = cond;
break;
case InstructionType.BType:
BTypeInstruction b = (BTypeInstruction)i;
b.cond = cond;
break;
case InstructionType.DType:
DTypeInstruction d = (DTypeInstruction)i;
d.cond = cond;
break;
}
}
// Determines which type of instruction to create based on if instruction is in a specific dictionary
// and creates a new instruction of that type. Instructions are in the form of lw, sw, add, bal, etc.
private Instruction CreateCorrectTypeOfInstruction(string instruction, int lineNum)
{
InstructionSubType subType;
Instruction i = null;
if (JInstructions.TryGetValue(instruction, out subType))
{
JTypeInstruction j = new JTypeInstruction();
j.instructionSubType = subType;
i = j;
}
else if (BInstructions.TryGetValue(instruction, out subType))
{
BTypeInstruction b = new BTypeInstruction();
b.instructionSubType = subType;
i = b;
}
else if (DInstructions.TryGetValue(instruction, out subType))
{
DTypeInstruction d = new DTypeInstruction();
d.instructionSubType = subType;
i = d;
}
else if (RInstructions.TryGetValue(instruction, out subType))
{
RTypeInstruction r = new RTypeInstruction();
r.instructionSubType = subType;
// Determines what the OpX bits should be based on the instruction given in the form add, sub, xor, etc.
r.OpX = (RTypeInstruction.Opx)Enum.Parse(typeof(RTypeInstruction.Opx), instruction);
i = r;
}
else
{
throw new InvalidInstructionException(String.Format("The instruction on line {0} is an invalid instruction.", lineNum));
}
return(i);
}