assignment4 - EE 306, Fall 2010 Programming Assignment 4;...

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EE 306, Fall 2010 Programming Assignment 4; Value: 20 points Due: Tuesday, December 7, 11:59 pm You must do the programming assignment by yourself. You are permitted to get help from ONLY the TAs, the instructor or one of the ECE tutors. The purpose of this assignment is to show how interrupt-driven Input/Output can interrupt a program that is running, execute the interrupt service routine, and return to the interrupted program, picking up exactly where it left off (just as if nothing had happened). In this assignment, we will use the Keyboard as the input device for interrupting the running program. The assignment consists of three parts: The user program . Your user program will consist of continually producing the "UT checkerboard" by alternately outputing two different lines. One line will consist of the pattern "UT followed by four spaces" eight times. The second line will consist of three spaces, and the pattern (UT followed by four spaces) seven times. UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT UT To ensure the output on the screen is not too fast to be seen by the naked eye, the user program should include a piece of code that will count down from 2500 each time a line is output on the screen. A simple way to do this is with the following subroutine named DELAY: DELAY ST R1, SaveR1 LD R1, COUNT REP ADD R1,R1,#-1 BRp REP LD R1, SaveR1 RET COUNT .FILL #2500 SaveR1 .BLKW 1
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The keyboard interrupt service routine . The keyboard interrupt service routine will simply write to the screen ten instances of whatever key the
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assignment4 - EE 306, Fall 2010 Programming Assignment 4;...

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