num dcd 27 ; 0b11011 mov r0, #num ldr r0, [r0] mov r2, r0 mov r1, #32 loop and r4, r2, #1 cmp r4, #1 bne itszero add r3, r3, #1 itszero lsr r2, r2, #1 sub r1, r1, #1 cmp r1, #0 bne loop end