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/*
ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file scheduler.h
* @brief Scheduler macros and structures.
*
* @addtogroup scheduler
* @{
*/
#ifndef _SCHEDULER_H_
#define _SCHEDULER_H_
/** @brief Default thread wakeup low level message.*/
#define RDY_OK 0
/** @brief Low level message sent to a thread awakened by a timeout.*/
#define RDY_TIMEOUT -1
/** @brief Low level message sent to a thread awakened by a reset operation.*/
#define RDY_RESET -2
#define NOPRIO 0 /**< @brief Ready list header priority. */
#define IDLEPRIO 1 /**< @brief Idle thread priority. */
#define LOWPRIO 2 /**< @brief Lowest user priority. */
#define NORMALPRIO 64 /**< @brief Normal user priority. */
#define HIGHPRIO 127 /**< @brief Highest user priority. */
#define ABSPRIO 255 /**< @brief Greatest possible priority. */
/**
* @brief Zero time specification for some syscalls with a timeout
* specification.
* @note Not all functions accept @p TIME_IMMEDIATE as timeout parameter,
* see the specific function documentation.
*/
#define TIME_IMMEDIATE ((systime_t)-1)
/**
* @brief Infinite time specification for all the syscalls with a timeout
* specification.
*/
#define TIME_INFINITE ((systime_t)0)
/**
* @brief Returns the priority of the first thread on the given ready list.
*/
#define firstprio(rlp) ((rlp)->p_next->p_prio)
/**
* @extends ThreadsQueue
*
* @brief Ready list header.
*/
typedef struct {
ThreadsQueue r_queue; /**< @brief Threads queue. */
tprio_t r_prio; /**< @brief This field must be
initialized to zero. */
struct context p_ctx; /**< @brief Not used, present because
offsets. */
#if CH_USE_REGISTRY
Thread *p_newer; /**< @brief Newer registry element. */
Thread *p_older; /**< @brief Older registry element. */
#endif
/* End of the fields shared with the Thread structure.*/
#if CH_TIME_QUANTUM > 0
cnt_t r_preempt; /**< @brief Round robin counter. */
#endif
#ifndef CH_CURRP_REGISTER_CACHE
Thread *r_current; /**< @brief The currently running
thread. */
#endif
} ReadyList;
#if !defined(__DOXYGEN__)
extern ReadyList rlist;
#endif
#ifdef CH_CURRP_REGISTER_CACHE
register Thread *currp asm(CH_CURRP_REGISTER_CACHE);
#else
#define currp rlist.r_current
#endif
/*
* Scheduler APIs.
*/
#ifdef __cplusplus
extern "C" {
#endif
void scheduler_init(void);
Thread *chSchReadyI(Thread *tp);
void chSchGoSleepS(tstate_t newstate);
msg_t chSchGoSleepTimeoutS(tstate_t newstate, systime_t time);
void chSchWakeupS(Thread *tp, msg_t msg);
void chSchDoRescheduleI(void);
void chSchRescheduleS(void);
bool_t chSchIsRescRequiredExI(void);
void chSchDoYieldS(void);
#ifdef __cplusplus
}
#endif
/**
* @brief Determines if yielding is possible.
* @details This function returns @p TRUE if there is a ready thread with
* equal or higher priority.
*/
#define chSchCanYieldS() (firstprio(&rlist.r_queue) >= currp->p_prio)
/**
* @brief Determines if the current thread must reschedule.
* @details This function returns @p TRUE if there is a ready thread with
* higher priority.
*/
#define chSchIsRescRequiredI() (firstprio(&rlist.r_queue) > currp->p_prio)
#endif /* _SCHEDULER_H_ */
/** @} */
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