.text
    .global main

main:
    push {r5, r6, lr}

    mov r0, #0
    mov r1, #1

    bl realloc

    mov r5, r0 // *values
    mov r6, #1 // counter

loop:
    mov r0, r5
    mov r2, #4
    mul r1, r6, r2
    bl realloc

    mov r5, r0

    ldr r0, stdin_label
    ldr r0, [r0]
    bl fgetc

    cmp r0, #-1
    beq print_reversed

    strb r0, [r5, r6]

    add r6, #1
    b loop

print_reversed:
    cmp r6, #1
    moveq r0, r5
    popeq {r5, r6, lr}
    bleq free
    bxeq lr

print_loop:
    cmp r6, #0
    moveq r0, r5
    bleq free
    popeq {r5, r6, lr}
    bxeq lr

    ldrb r0, [r5, r6]

    ldr r1, stdout_label
    ldr r1, [r1]
    bl fputc

    sub r6, #1
    b print_loop

stdin_label:
    .word stdin

stdout_label:
    .word stdout