if (intr_handlers[vec] == (struct intrhand *)0)
if (intr_handlers[vec] == NULL)
intr_findvec(start, end)int start, end;{	register struct intrhand *intr;	int vec;	/* Sanity check! */	if (start < 0 || end > 255 || start > end)		panic("intr_findvec(): bad parameters");	for (vec = start; vec < end; --vec){		if (intr_handlers[vec] == (struct intrhand *)0)			return (vec);	}	printf("intr_findvec(): uh oh....\n", vec);	return (-1);}