CS 210

PROJECT #1                                     Due: Noon Friday 02/23/07

     This project introduces students to the design of a system program, 
written in Linux assembly language, that can display some information on
the terminal screen in a prescribed format.


                           PROBLEM STATEMENT

     Write an assembly language program (named 'today.s') that will show
today's date in the 'dd mmm yyyy' format (i.e., day, month, year), where
'dd' is a two-digit number, 'mmm' is a three-letter abbreviation for the
current month, and 'yyyy' is a four-digit number for the current year:

          HERE IS A SAMPLE TERMINAL-SESSION:   

			$ ./today 
			12 FEB 2007
			$

(It is a requirement of this assignment that your 'today.s' source-file
should include all of your program-code; in other words, you should not
'link' your program to any external modules or any standard libraries.)


			     BACKGROUND

     The Linux operating system provides a system-call named 'sys_time'
that can be used by an application program to find out the exact number 
of seconds that have elapsed since midnight on January 1, 1970.  So you
could get the number of days that have passed since 1970 if you divided
by the number of seconds in each day (i.e., by 60*60*24).  Some further
arithmetic operations, based on your knowledge of the calendar, provide
your program with the current year, month, and day-of-the-month.  (Look
in a header-file named "/usr/src/linux/include/asm/unistd.h" to get the
system-call ID-number for the 'sys_time' system-call; look at the 'man'
page for the 'time()' library-function to discover what parameters this
function expects and what value it will return.)


			     WHAT TO SUBMIT

     Your project-submission has two required parts: 
	(1) a printout of your source-file (i.e., 'today.s');
	(2) electronic copies of all your program-files; 
Use the 'ljpages' utility-program (under 'System Software' on our cs210
website) to produce your printout on a laserprinter in our classroom or
in one of the Harney Fifth-Floor CS Labs -- Be sure your printout shows
YOUR NAME as the project's programmer -- and turn in your 'printout' to 
the instructor's mailbox (Mathematics Office: Harney-222).  Submit your
program files (i.e., 'today.s', 'today.o', and 'today') by copying them 
into your '/submit' directory, where your instructor can them for doing
testing and grading:

	   $ cp today* /home/submit/cs210/<your_directory>/.
________________________________________________________________________
Allan B. Cruse          University of San Francisco          Spring 2007