Send e-mail questions to Somayeh Sardashti, somayeh@cs.wisc.edu
Due Friday, November 6, before 5pm.

Goals of this Assignment

The goal of this assignment is to understand conventions for parameter passing and register usage with respect to implementing functions. Towards that end, you will be given two separate, partial MAL assembly language programs with functions to complete.

The First Program

The first program (called ints.s) loops, requesting an integer, reading an integer, and then printing the integer entered. The printing of the integer is to be accomplished by a missing print_integer() function. Find this program at

/p/course/cs354-common/public/html/homeworks/ints.s

Do not forget to completely document the function.

The Second Program

The second program (called powers.s) has functionality similar to assignment 1, the C program. The major difference is that for this program, input is prompted from the user, instead of using command line arguments. Find this second program at

/p/course/cs354-common/public/html/homeworks/powers.s

• print_integer()
• setPowers()
setPowers() receives 4 parameters, which are exactly as defined for assignment 1. The first parameter is the user entered integer that will be raised to the various powers. The second parameter is base address of the array. The third parameter is the lower bound exponent, and the last parameter is the upper bound exponent. For each of the integers in the range, this function calls power(), and then places the return value into the array.
• power()
power() calculates and returns (in $v0) the correct power. The two parameters are exactly as defined for assignment 1: the first parameter is the base, and the second parameter is the exponent.
• print()
print() does the output for the program. For each power calculated, there is one line of output, formatted just as in assignment 1. print() receives 4 parameters, which are exactly as defined for assignment 1. The first parameter is base address of the array. The second parameter is the user entered integer that was raised to the various powers. The third parameter is the lower bound exponent, and the last parameter is the upper bound exponent. For each and every integer to be printed, this function calls print_integer().

Note that the print_integer() procedure is exactly the same for both programs. A goal of this assignment is to realize that any program that follows the conventions for parameter passing and register usage can utilize the same function code.

Also note that both setPowers() and print() are both a caller and a callee.

Requirements

1. Your code must follow style guidelines as given in Style Guidelines.

   Place your name (and your partner's name, if working in a pair) at the top of the source code within both files.

   See Guidelines for Programs to see an indication of point allocation used in program grading.

2. The two files ints.s and powers.s will be turned in. They must have these names to make the lab-supported handin program work.
3. Follow all parameter passing and register usage conventions as described in MIPS register usage. This program will have a lot of points dedicated to the following of the conventions.
4. Do not change code outside of the functions you are writing, other than to put your name(s) at the top of each file.

Notes

Remember that the I/O instructions getc, putc, and puts are implemented as functions within the operating system's code, and they overwrite registers $v0 and $4 (alias $a0).

Collaboration Policy

For this assignment, you may work in pairs (2 people). All students (whether working in a pair or not) must individually turn in the assignment by individually running the handin program. Therefore, 2 copies of the assignment will be turned in for those working as a pair. The grader will choose to grade only one copy of a pair's work, and assign the same score to both students.

If working in a pair, the names of BOTH students must appear at the top of the turned in assignment.

Handing In the Program

Your MAL source code must be in the 2 files named ints.s and powers.s. Turn in your program by running the lab-supported handin program.

Use the following command to run the handin program:

  /s/handin/bin/handin -c cs354-1 -a a4 -d .