Function ffclock_read_counter

freebsd/kern/kern_tc.c:873–894

* Access to current ffcounter value. */

 * Access to current ffcounter value.
 */
void
ffclock_read_counter(ffcounter *ffcount)
{
	struct timehands *th;
	struct fftimehands *ffth;
	unsigned int gen, delta;

	/*
	 * ffclock_windup() called from tc_windup(), safe to rely on
	 * th->th_generation only, for correct delta and ffcounter.
	 */
	do {
		th = timehands;
		gen = atomic_load_acq_int(&th->th_generation);
		ffth = fftimehands;
		delta = tc_delta(th);
		*ffcount = ffth->tick_ffcount;
		atomic_thread_fence_acq();
	} while (gen == 0 || gen != th->th_generation);

	*ffcount += delta;
}

void
binuptime(struct bintime *bt)