Python Assembler

This python program processes a text file containing the basic computer assembly instructions (the one from the 70s) and generates machine code in different formats (binary, hexadecimal, or decimal). The output is saved in the same working directory in output.txt.

Features

• Parses basic computer assembly code to generate machine code.
• Supports labels and builds a symbol-address table during the first pass.
• Allows output customization with multiple format flags.
• Provides detailed error messages for invalid syntax and file handling issues.
• Includes a pretty-printed symbol-address table.

Usage

To execute the program, simply use the following command:

python <file_name> file.txt output.txt [flags]

Where:

• asm.txt is the assembly file you want to process.
• output.txt is the name which you want the output to be.

Flags

• -b: Outputs machine code in binary (default).
• -h: Outputs machine code in hexadecimal.
• -d: Outputs machine code in decimal.
• -st: Displays the Symbolic Table in the terminal in a pretty-printed format.

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Example Usage

python .\main.py asm-instr.txt output.txt -h -st

This will

1. Generate machine code in hexadecimal format
2. Displays the symbol-address table in the terminal.

How it works

1. First Pass: The program scans the input file to build a symbol-address table for all labels defined in the assembly code.

2. Second Pass: The program processes instructions, translates them to machine code, and applies the selected output format.

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Example Input

        ORG 100 /Origin is at memory location 100
        LDA SUB /Load 'SUB' into AC
        CME     /Complement AC
        INC     /Increment AC
        ADD MIN /ADD 'MIN' to AC
        STA DIF /Store the result in 'DIF'
        HLT     /Halt Computer
MIN,    DEC 83  /Minuend
SUB,    DEC -23 /Subtrahend
DIF,    HEX 0   /Result
        END     /End of symbolic program

Example Ouput (using -h flag)

100	2107
101	7100
102	7020
103	1106
104	3108
105	7001
106	0053
107	FFE9
108	0000

Dependencies

• prettytable: For displaying the symbolic table in a user-friendly way.
  • To install, use:

   pip install prettytable

Project Structure

• main.py: The main entry point.
• helpers.py: Contains the instruction table necessary to translate the code (MRI and Non-MRI).

Suggested Improvements

• Using python to run the assembly code. Outputs the variables' latest state or sth.