UMBC CMSC 313, Computer Organization & Assembly Language, Fall 2002, Section 0101

Project 1: Bleeper

Also available in PDF.

Due: Thursday September 19, 2002


This project is a finger-warming exercise to make sure that everyone can compile an assembly language program, run it through the debugger and submit the requisite files using the systems in place for the programming projects.


For this project, you must do the following:
  1. Modify the assembly language program 'toupper.asm' as follows. Replace all occurrences of the punctuation marks !, @, # and % with a period. For example, the input string
    What the @#!%!! is going on here?
    should be converted to
    What the ...... is going on here?
    Alphabetic characters, digits and punctuation marks other than !, @, # and % should be left unchanged. Also, you will find the conditional jump instructions je and jne to be useful.
  2. Using the UNIX script command, record some sample runs of your program and a debugging session using gdb. In this session, you should fully exercise the debugger. You must set several breakpoints, single step through some instructions, use the automatic display function and examine the contents of memory before and after processing. The script command is initiated by the command script. This puts you in a new UNIX shell which records every character typed or printed to the screen. You exit from this shell by typing exit at the UNIX prompt. A file named typescript is placed in the current directory.
The source code for toupper.asm is available on the GL file system in: /afs/

Turning in your program

Use the UNIX submit command on the GL system to turn in your project. You should submit two files: 1) the modified assembly language program and 2) the typescript file of your debugging session. The class name for submit is cs313-0101 and the project name is proj1. The UNIX command to do this should look something like:

submit cs313-0101 proj1 bleeper.asm typescript


Additional help on running NASM, gdb and making system calls in Linux are available on the assembly language programming web page for this course.

Recall that the project policy states that programming assignments must be the result of individual effort. You are not allowed to work together. Also, your projects will be graded on five criteria: correctness, design, style, documentation and efficiency. So, it is not sufficient to turn in programs that assemble and run. Assembly language programming can be a messy affair --- neatness counts.

Last Modified: 12 Sep 2002 11:56:43 EDT by Richard Chang
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