Question

Write a MIPS program that multiples every element in an array of size 10 by 4 without using the multiply instruction.

Answer 1

.data
arr: .word 1, 2, 3, 4, 5, 6, 7, 8, 9, 10   # array with 10 elements
.text
.globl main
main:
   la $t0, arr                      # loading base address of arr to $t0
   li $t1, 10               # loading array size to $t1
   li $t2, 0                                           # initializing loop counter to 0
  
multiply:
   beq $t2, $t1, end              # if counter>array size, break the loop
   sll $t3, $t2, 2                                # calculating offset address
   add $t3, $t3, $t0                            # adding offset address and base address to get effective address
   lw $t4, ($t3)                                   # getting value from the array
   sll $t4, $t4, 2                               # multiplying the value by 2, using shift instruction
   sw $t4, ($t3)                                 # storing number back to array
   addi $t2, $t2, 1           # increamenting counter
   j multiply              # looping again

end:
   li $v0, 10
   syscall