Question

Prompt user to enter an integer number from console. Use 2 methods to multiply this number by factor 7, display result.

This is required to be done in MIPS Assembly Language.

Answer 1

Method 1: Multiplication is defined as add the multiplier(m) to the itself the number of time in the multiplicand(n) time. Thus a definition is the following: M(m,n) = m(when n = 1), else will be M(m, n-1) Here we are taking n=7 as we have to multiply it with 7

This is done in pseudo code here.

subprogram global main()

{

register int multiplicand

register int multiplier

register int answer

m = prompt("Enter the multiplicand")

n = prompt("Enter the multiplier")

answer = Multiply(m, n)

print("The answer is: " + answer)

}

subprogram int multiply(int m, int n)

{

if (n == 1)

return m;

return m + multiply(m,n-1)

}

Method 2: Put n=7 for multiplying by 7

.text

.globl main

main:

# register conventions

# $s0 - m

# $s1 - n

# $s2 - answer

la $a0, prompt1 # Get the multiplicand

jal PromptInt

move $s0, $v0 la $a0, prompt2 # Get the multiplier

jal PromptInt

move $s1, $v0

move $a0, $s0

move $a1, $s1

jal Multiply # Do multiplication

move $s2, $v0

la $a0, result #Print the answer

move $a1, $s2

jal PrintInt

jal Exit

Multiply:

addi $sp, $sp -8 # push the stack

sw $a0, 4($sp) #save $a0

sw $ra, 0($sp) # Save the $ra

seq $t0, $a1, $zero # if (n == 0) return

addi, $v0, $zero, 0 # set return value

bnez $t0, Return

addi $a1, $a1, -1 # set n = n-1

jal Multiply # recurse

lw $a0, 4($sp) # retrieve m

add $v0, $a0, $v0 # return m+multiply(m, n-1)

Return:

lw $ra, 0($sp) #pop the stack

addi $sp, $sp, 8

jr $ra

.data

prompt1: .asciiz "Enter the multiplicand: "

prompt2: .asciiz "Enter the multiplier: "

result: .ascii "The answer is: "

.include "utils.asm"