28. Example adding three numbers

• 
  # Add three numbers in memory and print the result
  
      .data
  
  # string to print before the result
  STR_PROMPT: .asciiz "Result: "
  
  # numbers to add
  nums:   .word -77, 13, -5    # numbers to add
  result: .word 0              # result
  
      .text
  
       # print the initial string
       li      $v0, 4          # ask for print string service
       la      $a0, STR_PROMPT
       syscall
  
       # load three numbers into registers
       la     $t0, nums
       lw     $t1, 0($t0)      # lw $t1, nums
       lw     $t2, 4($t0)      # lw $t2, nums + 4
       lw     $t3, 8($t0)      # lw $t3, nums + 8
       
       # add and store the result in $a0 for printing
       add     $a0, $t1, $t2   # add the first two numbers
       add     $a0, $a0, $t3   # add the third to the sum
       
       # save a0 in memory
       sw      $a0, result
  
       # print the result
       li      $v0, 1          # ask for $a0 print service
       syscall
       
       # exit
       li      $v0, 10         # ask for exit service
       syscall