extrn	data(onda,ASC,DESC)

cseg	at	03h
	jmp	extint0

cseg	at	13h
	jmp	extint1
	
extint0	segment code
	rseg	extint0
	push	acc
	mov	a,onda
	cjne	a,#ASC,decrementa
	mov	onda,#DESC
	jmp	sai0

decrementa:
	dec	onda

sai0:	pop	acc
	reti

extint1	segment code
	rseg	extint1
	push 	acc
	mov	a,onda
	cjne	a,#DESC,incrementa
	mov	onda,#ASC
	jmp	sai1
	
incrementa:
	inc	onda

sai1:	pop	acc
	reti

end