03-2

    .text
    .global sort_by_age

swap:
    @r0 == N
    @r1 == *person_tsons
    @r2 == ind_1
    @r3 == ind_2
    push {r4, r5, r6, lr}
    mov r4, #0
swap_loop:
    cmp r4, #12
    beq swap_ret
    ldr r5, [r1, r2]
    ldr r6, [r1, r3]
    str r5, [r1, r3]
    str r6, [r1, r2]
    add r2, #4
    add r3, #4
    add r4, #1
    b swap_loop
swap_ret:
    sub r2, #48
    sub r3, #48
    pop {r4, r5, r6, pc}


sort_by_age:
    push {r4, r5, r6, lr}
    mov r4, #48
    mul r0, r4
    mov r4, #0
main_loop:
    cmp r4, r0
    beq ret
    mov r2, #0
    add r3, r2, #48
second_loop:
    cmp r3, r0
    beq second_loop_end
    add r2, #4
    add r3, #4
    ldrb r5, [r1, r2]
    ldrb r6, [r1, r3]
    sub r2, #4
    sub r3, #4
    cmp r6, r5
    bllt swap
    add r2, #48
    add r3, #48
    b second_loop
second_loop_end:
    add r4, #48
    b main_loop
ret:
    pop {r4, r5, r6, pc}