Question

Write a MIPS program that executes the statement: s = (a + b) – (c + 101), where a, b, and c are

user provided integer inputs, and s is computed and printed as an output. Answer the following:

a. Suppose the user enters a = 5, b = 10, and c = -30, what is the expected value of s?

b. Which instruction in your program computed the value of s and which register is used?

c. What is the address of this instruction in memory?

d. Put a breakpoint at this instruction and write the value of the register used for computing s in

decimal and hexadecimal.

Answer 1

MIPS PROGRAM

.data
   askA: .asciiz "Enter value of a: "
   askB: .asciiz "Enter value of b: "
   askC: .asciiz "Enter value of c: "
   msgS: .asciiz "Result s: "
.text
   # Prompt user to enter value of a
   li $v0, 4
   la $a0, askA
   syscall
   # Get user input
   li $v0, 5
   syscall
   #store the result in t0
   move $t0, $v0
  
   # Prompt user to enter value of b
   li $v0, 4
   la $a0, askB
   syscall
   # Get user input
   li $v0, 5
   syscall
   #store the result in t1
   move $t1, $v0
  
   add $t2, $t0, $t1
  
   # Prompt user to enter value of c
   li $v0, 4
   la $a0, askC
   syscall
   # Get user input
   li $v0, 5
   syscall
   #store the result in t0
   move $t0, $v0
  
   add $t1,$t0,101
  
   sub $t0,$t2,$t1
  
   li $v0, 4
   la $a0, msgS
   syscall
   #print or show the age
   li $v0, 1
   move $a0, $t0
   syscall

Explanation

$t0 = a

$t1 = b

$2 = $t0 + $t1

$t0 = c

$t1 = $t0 + 101

$t0 = $t2 - $t1

Qa Ans) -56

Qc Ans )

Qb Ans)

sub $t0,$t2,$t1

Qd Ans)

Hexadecimal

Decimal