.data
format:
    .asciz  "<%d>\n"

    .text
    .align  2
    .global main
main:
    push    {r5, fp, lr}
    mov     fp, sp
    mov     r5, #0
    sub     sp, sp, #4
loop:
    sub     sp, sp, #4
    bl      getchar

    cmp     r0, #-1
    add     r5, r5, #1
    strne   r0, [sp]
    bne     loop

    b       reverse_loop

reverse_loop:
    sub     r5, r5, #1
    cmp     r5, #0
    beq     default

    add     sp, sp, #4
    ldr     r0, [sp]
    bl      putchar

    b       reverse_loop

default:
    //mov       r1, r5
    //ldr       r0, =format
    //bl        printf

    mov     sp, fp
    pop     {r5, fp, lr}
    bx      lr