Function loadtimer

freebsd/kern/kern_clocksource.c:378–418

* Load new value into hardware timer. */

 * Load new value into hardware timer.
 */
static void
loadtimer(sbintime_t now, int start)
{
	struct pcpu_state *state;
	sbintime_t new;
	sbintime_t *next;
	uint64_t tmp;
	int eq;

	if (timer->et_flags & ET_FLAGS_PERCPU) {
		state = DPCPU_PTR(timerstate);
		next = &state->nexttick;
	} else
		next = &nexttick;
	if (periodic) {
		if (start) {
			/*
			 * Try to start all periodic timers aligned
			 * to period to make events synchronous.
			 */
			tmp = now % timerperiod;
			new = timerperiod - tmp;
			if (new < tmp)		/* Left less then passed. */
				new += timerperiod;
			CTR5(KTR_SPARE2, "load p at %d:   now %d.%08x first in %d.%08x",
			    curcpu, (int)(now >> 32), (u_int)(now & 0xffffffff),
			    (int)(new >> 32), (u_int)(new & 0xffffffff));
			*next = new + now;
			et_start(timer, new, timerperiod);
		}
	} else {
		new = getnextevent();
		eq = (new == *next);
		CTR4(KTR_SPARE2, "load at %d:    next %d.%08x eq %d",
		    curcpu, (int)(new >> 32), (u_int)(new & 0xffffffff), eq);
		if (!eq) {
			*next = new;
			et_start(timer, new - now, 0);
		}
	}
}

/*
 * Prepare event timer parameters after configuration changes.