os161/kern/include/clock.h
2015-12-23 00:50:04 +00:00

84 lines
2.6 KiB
C

/*
* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
* The President and Fellows of Harvard College.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _CLOCK_H_
#define _CLOCK_H_
/*
* Time-related definitions.
*/
#include <kern/time.h>
/*
* hardclock() is called on every CPU HZ times a second, possibly only
* when the CPU is not idle, for scheduling.
*/
/* hardclocks per second */
#define HZ 100
void hardclock_bootstrap(void);
void hardclock(void);
/*
* timerclock() is called on one CPU once a second to allow simple
* timed operations. (This is a fairly simpleminded interface.)
*/
void timerclock(void);
/*
* gettime() may be used to fetch the current time of day.
*/
void gettime(struct timespec *ret);
/*
* arithmetic on times
*
* add: ret = t1 + t2
* sub: ret = t1 - t2
*/
void timespec_add(const struct timespec *t1,
const struct timespec *t2,
struct timespec *ret);
void timespec_sub(const struct timespec *t1,
const struct timespec *t2,
struct timespec *ret);
/*
* clocksleep() suspends execution for the requested number of seconds,
* like userlevel sleep(3). (Don't confuse it with wchan_sleep.)
*/
void clocksleep(int seconds);
#endif /* _CLOCK_H_ */