AVR Assembly simple debouncer

debouncer.asm

;example program using debouncing
;from AVR Programming by Elliot Williams p.115
;
;compile with gavrasm debouncer.asm
;flash with avrdude -c avrisp -p m168 -P /dev/tty.usbmodem1411 -b 19200 -U flash:w:debouncer.hex
;
.def temp = r16 
.device atmega168
;--- inits ---
.def b_pressed = r17 
.def eoReg = r18 
        sbi     PORTD,PD2       ;set pullup bit on button
        sbi     DDRB,PB0        ;set ddr output on led pin
loop:   
        rcall   debounce
        brcc    else
        tst     b_pressed
        brne    loop
        in      temp,PORTB
        ldi     eoReg,(1 << PB0)
        eor     temp,eoReg
        out     PORTB,temp
        ldi     b_pressed,1
        rjmp    loop
else:
        ldi     b_pressed,0
        rjmp    loop
;--- suboutines ---
debounce:
.equ d_time = 1000
        sbic    PIND,PD2        ;bit is clear=button is pressed
        rjmp    bitSet
        ldi     r25,high(d_time)
        ldi     r24,low(d_time) 
delay:  sbiw    r25:r24,1
        brne    delay
        sbic    PIND,PD2        ;button still pressed?
        rjmp    bitSet
        sec 
        ret 
bitSet:
        clc 
        ret