CS274: Computer Architecture - MIPS Iteration

Activity Goals

The goals of this activity are:
  1. To implement iterative algorithms using the MIPS assembly language

The Activity

Directions

Consider the activity models and answer the questions provided. First reflect on these questions on your own briefly, before discussing and comparing your thoughts with your group. Appoint one member of your group to discuss your findings with the class, and the rest of the group should help that member prepare their response. Answer each question individually from the activity, and compare with your group to prepare for our whole-class discussion. After class, think about the questions in the reflective prompt and respond to those individually in your notebook. Report out on areas of disagreement or items for which you and your group identified alternative approaches. Write down and report out questions you encountered along the way for group discussion.

Model 1: An iterative MIPS program

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
.text
.globl main
  
main:
    # print user prompt string
    li $v0, 4
    la $a0, input
    syscall   
     
guess:
    # read integer - will be copied to v0
    li $v0, 5
    syscall
     
    # our secret number is 7!
    li $s0, 7
     
    # if v0 == our secret number s0
    beq $s0, $v0, correct
     
    # incorrect code
    li $v0, 4
    la $a0, wrong
    syscall      
     
    # loop until the user gets it right
    j guess
 
correct:
    li $v0, 4
    la $a0, right
    syscall      
     
exit:
    # exit
    li $v0, 10
    syscall 
     
.data
    input: .asciiz "Can you guess my secret number between 1 and 10?  Enter it below\n"
    wrong: .asciiz "Not quite!\n"
    right: .asciiz "You guessed it!\n"

Questions

  1. What kind of loop do you see depicted in this program?

Model 2: Implementing Loops in MIPS

?
1
2
3
4
5
6
7
8
9
10
int main(void) {
    int sum = 0;
    int i = 0;
     
    for(i = 0; i < 10; i++) {
        sum = sum + 1;
    }
     
    printf("%d", sum);
}

?
1
2
3
4
5
6
7
int main(void) {
    int num = 0;
    do {
        printf("Enter a number between 1 and 10\n");
        scanf(" %d", &num);
    } while(num < 1 || num > 10);
}

Questions

  1. Translate each of the above C code listings into a MIPS assembly program

Submission

I encourage you to submit your answers to the questions (and ask your own questions!) using the Class Activity Questions discussion board. You may also respond to questions or comments made by others, or ask follow-up questions there. Answer any reflective prompt questions in the Reflective Journal section of your OneNote Classroom personal section. You can find the link to the class notebook on the syllabus.