xnu-1228.12.14.tar.gz

[apple/xnu.git] / osfmk / kern / timer.c

/*
 * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/* 
 */

#include <stat_time.h>
#include <machine_timer_routines.h>

#include <mach/kern_return.h>
#include <mach/port.h>
#include <kern/queue.h>
#include <kern/processor.h>
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <kern/timer.h>

/*
 *	timer_init initializes a timer.
 */
void
timer_init(
	timer_t		timer)
{
#if	!STAT_TIME
	timer->tstamp = 0;
#endif	/* STAT_TIME */
	timer->low_bits = 0;
	timer->high_bits = 0;
	timer->high_bits_check = 0;
}

/*
 *	Calculate the difference between a timer
 *	and saved value, and update the saved value.
 */
uint64_t
timer_delta(
	timer_t		timer,
	uint64_t	*save)
{
	uint64_t	new, old = *save;

	*save = new = timer_grab(timer);

	return (new - old);
}

void
timer_advance(
	timer_t		timer,
	uint64_t	delta)
{
	uint64_t	low;

	low = delta + timer->low_bits;
	if (low >> 32)
		timer_update(timer, timer->high_bits + (low >> 32), low);
	else
		timer->low_bits = low;
}

#if	!STAT_TIME

void
timer_start(
	timer_t		timer,
	uint64_t	tstamp)
{
	timer->tstamp = tstamp;
}

void
timer_stop(
	timer_t		timer,
	uint64_t	tstamp)
{
	timer_advance(timer, tstamp - timer->tstamp);
}

/*
 *	Update the timer and start a new one.
 */
void
timer_switch(
	timer_t			timer,
	uint64_t		tstamp,
	timer_t			new_timer)
{
	timer_advance(timer, tstamp - timer->tstamp);
	new_timer->tstamp = tstamp;
}

#if	MACHINE_TIMER_ROUTINES

/*
 *	Machine-dependent code implements the timer event routine.
 */

#else	/* MACHINE_TIMER_ROUTINES */

/*
 *	Update the current thread timer and
 *	start the new timer.  Requires a current
 *	and new timer.
 *
 *	Called with interrupts disabled.
 */
void
thread_timer_event(
	uint64_t		tstamp,
	timer_t			new_timer)
{
	processor_t		processor = current_processor();
	timer_t			timer;

	/*
	 *	Update current timer.
	 */
	timer = PROCESSOR_DATA(processor, thread_timer);
	timer_advance(timer, tstamp - timer->tstamp);

	/*
	 *	Start new timer.
	 */
	PROCESSOR_DATA(processor, thread_timer) = new_timer;
	new_timer->tstamp = tstamp;
}

#endif	/* MACHINE_TIMER_ROUTINES */

#endif	/* STAT_TIME */