.device atmega168

.equ DDRB = 4
.equ PORTB = 5

ldi r16, $20 ; we're going to input data
out DDRB, r16 ; copy it to DDRB

ldi r17, $0 ; set counters to 0
ldi r18, $0 ; ^
ldi r19, $0 ; ^

jmp _start

_led_on:
    ldi r16, $20
    out PORTB, r16 ; turns on led
    ret

_led_off:
    ldi r16, $0
    out PORTB, r16 ; turns off led
    ret

_wait:
    inc r17 ; increment 17
    cpi r17, $FF ; until it hits FF
    brlo _wait ; jumps to _wait if it's not FF yet

    inc r18
    cpi r18, $FF
    brlo _wait

    inc r19
    cpi r19, $10
    brlo _wait

    ldi r17, $0
    ldi r18, $0
    ldi r19, $0
    ret


_start:
    call _wait
    call _led_on
    call _wait
    call _led_off
    jmp _start