Pass2 Algorithm

Pass 2 code

def Pass2(assembly_code, SymbolTable): ​

# Initialize an empty list for the machine code output​

​

machine_code = []​

• # Iterate through each line of the assembly code (Intermediate Representation)​

for line in assembly_code:​

     # Remove any leading/trailing whitespaces​

     line = line.strip()​

• ​

     # Handle label resolutions for instructions​

     if ":" in line:  # It's a label (skip it in code generation)​

         line = line.split(":")[1].strip()  ​

# Check if the line is an instruction (e.g., ADD, LDR, MOV, etc.)​

     if line.startswith("LDR") or line.startswith("ADD") or line.startswith("MOV"):  ​

         # Extract the instruction and operands (e.g., "LDR R1, =num1")​

         parts = line.split()  # Split by space to separate instruction and operands                  instruction = parts[0]  ​

       operands = part s[1:] ​

# Process operands to resolve labels​

         for i in range(len(operands)):​

             operand = operands[i]​

             ​

             if operand.startswith("="):  # It's a label reference (e.g., "=num1")​

                 label = operand[1:]  # Strip the '=' sign to get the label (e.g., "num1")​

                 if label in SymbolTable:  # If the label exists in the Symbol Table​

                     # Replace the label with its corresponding address​

                     operands[i] = hex(SymbolTable[label])  # Use hex address from Symbol Table​

                 else:​

                     raise ValueError(f"Label {label} not found in Symbol Table.")

     # Translate the instruction into machine code (this is a simplified example)​

         # The translation process can be more complex based on the instruction set architecture​

         if instruction == "LDR":​

             # Example: translating LDR R1, =num1 to a machine code instruction​

             # For simplicity, assume we're directly generating a machine code byte sequence (this is highly simplified)​

             machine_code.append(f"LDR {operands[0]}, {operands[1]}")  # For demonstration​

         elif instruction == "ADD":​

             # Similar translation for ADD​

             machine_code.append(f"ADD {operands[0]}, {operands[1]}, {operands[2]}")​

         elif instruction == "MOV":​

             # Translate MOV instruction​

             machine_code.append(f"MOV {operands[0]}, {operands[1]}")​

​

     # Add more cases for different instructions as needed...​

​

# Return the list of machine code instructions​

return machine_code