.text
.global main
main:
    mov r1, #0
    mov r2, #1

loop:
    mov r3, #0
    add r3, r1, r2
    add r2, r2, #1
    cmp r2, #22
    bgt end
    str r3, [r1]
    b loop

end:
    ldr r0, [r3]
    bx lr