Pass1 Algorithm

Pass 1 code:

def Pass1(assembly_code):​

# Initialize the Location Counter (LC) and Symbol Table​

LC = 0             ​

SymbolTable = {}     ​

​

# Iterate over each line of the assembly code​

for line in assembly_code:​

     ​

     # Check if the line contains a label (a label is followed by ':')​

     if ":" in line:​

         # Extract label from the line​

         label = line.split(":")[0].strip()  # Label is before the ':'​

         ​

         # Add the label and its corresponding LC to the Symbol Table​

         SymbolTable[label] = LC​

         ​

# Continue to the next line without incrementing LC for labels​​

         continue​​

     ​​

     # If the line contains data or instruction, determine its type​​

     # (e.g., if it's a directive like `.word`, `.space`, or an instruction like `ADD`)​​

     if line.startswith("."):  # If it's a directive (e.g., .word, .data)​​

         LC += size_of_data(line)  # Update LC based on data size (e.g., 4 bytes for `.word`)​​

     else:  # If it's an instruction (e.g., ADD, LDR, etc.)​​

         LC += 4  # ARM instructions are usually 4 bytes in length​​

​​

# Return the Symbol Table with labels and their resolved addresses​​

return SymbolTable​