Menge-Push Character

Di tahap berikutnya, character yang berasal dari buffer di push ke dalam stack. Character kemudian ditest apakah null atau tidak, kalau tidak maka character akan dimasukkan ke stack, kalau iya maka loop akan berhenti.

# Reverse and output a user-supplied string
#
# Settings: Load delays OFF; Branch delays OFF,
#           Trap file    ON; Pseudoinstructions ON   
#
# $t0 --- character pushed or popped
# $t1 --- index into string buffer str

        .text
        .globl  main

main:   #input the string
        li      $v0,8          # service code
        la      $a0,str        # address of buffer
        li      $a1,128        # buffer length 
        syscall
        
        li      $t0,0          # push a null 
        subu    $sp,$sp,4      # onto the stack
        sw      $t0,($sp)      # to signal its bottom
        li      $t1,0          # index of first char in str buffer
        
        # push each character onto the stack
pushl:
        lbu     $t0,str($t1)   # get current char into
                               # a full word
             $t0,stend    # null byte: end of string
        
        subu    $sp,$sp,4      # push the full word
              $t0,($sp)   # holding the char
        
        addu    $t1,1          # inc the index
        j                 # loop

stend:           
        . . . . .

        # pop chars from stack back into the buffer

        # print the reversed string
        
        .data
str:    .space  128            # character buffer 

Quest 13: Fill in the blank