Description
Purpose: Become familiar with the tool chain → the assembler, linker, and debugger. Refresh
concepts regarding data representation including binary, decimal, and hex. Display values
in memory for integers, reals, and characters.
Points: 25
Assignment:
Part A:
Write a simple assembly language program to compute the following formulas:
bAns1 = bVar1 + bVar2
bAns2 = bVar1 – bVar2
wAns1 = wVar1 + wVar2
wAns2 = wVar1 – wVar2
dAns1 = dVar1 + dVar2
dAns2 = dVar1 – dVar2
Declare the following variables in the data segment (after the “.data”).
bVar1 db 59
bVar2 db 21
bAns1 db 0
bAns2 db 0
wVar1 dw 2681
wVar2 dw 1432
wAns1 dw 0
wAns2 dw 0
dVar1 dd 164641512
dVar2 dd 112356789
dVar3 dd -46524
dAns1 dd 0
dAns2 dd 0
qVar1 dq 142455214619
flt1 dd -19.125
flt2 dd 11.25
eVal dd 2.71828
myClass db “CS-218”, NULL
saying db “Its not a bug, its a feature.”, NULL
myName db “your name goes here”, NULL
Be sure to replace the “your name goes here” with your actual name (in quotes). Fail to replace
your name will result in a 10% penalty.
Part B:
Complete the Assignment #2 – Data Representation Worksheet on the class web page. Note, the
data representation worksheet will not be accepted late.
Submission:
• All source files must assemble and execute on Ubuntu with yasm.
• Submit source files
◦ Submit a copy of the program source file via the on-line submission
• Once you submit, the system will score the project and provide feedback.
◦ If you do not get full score, you can (and should) correct and resubmit.
◦ You can re-submit an unlimited number of times before the due date/time.
• Late submissions will be accepted for a period of 24 hours after the due date/time for any given
assignment. Late submissions will be subject to a ~2% reduction in points per an hour late. If
you submit 1 minute – 1 hour late -2%, 1-2 hours late -4%, … , 23-24 hours late -50%. This
means after 24 hours late submissions will receive an automatic 0.
Program Header Block
All source files must include your name, section number, assignment, NSHE number, and program
description. The required format is as follows:
; Name:
; NSHE ID:
; Section:
; Description:
Failure to include your name in this format will result in a loss of up to 20%.
Scoring Rubric
Scoring will include functionality, code quality, and documentation. Below is a summary of the
scoring rubric for this assignment.
Criteria Weight Summary
Assemble – Failure to assemble will result in a score
of 0.
Program Header 20% Must include header block in the
required format (see above).
General Comments 20% Must include an appropriate level of
program documentation.
Program Functionality
(and on-time)
60% Program must meet the functional
requirements as outlined in the
assignment. Must be submitted on time
for full score.
Debugger Commands:
Execute the program in the debugger (in the same manner as assignment #1). You should review the
DDD/GDB debugger information handout to understand the debugger commands examine memory
variables.
You may use the provided “a2in.txt” to display the variables with the debugger.
• Each byte, word, double-word sized, and quadword variable is displayed twice (once in decimal
and again in hex).
• The floating point values are display twice (once as a real value and again in hex).
• The strings are displayed twice, once showing both the decimal and ASCII values and then just
the hex values for the first six characters
A brief summary of the command to examine memory is as follows:
x/ & Examine memory location
number of locations to display, 1 is defualt.
format: d – decimal
x – hex
u – unsigned
c – character
s – string
f – floating point
unit size: b – byte (8-bits)
h – halfword (16-bits)
w – word (32-bits)
g – giant (64-bits)
For example, to display the 16-bit variable wVar2 and the 32-bit variable dVar1, the commands would
be as follows:
x/dh &wVar2
x/dw &dVar1
x/dg &qVar1
For future assignments you will need to select the correct command to display the data based on the
defined size and any guidance from the assignment.
