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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011 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 chschd.h
* @brief Scheduler macros and structures.
*
* @addtogroup scheduler
* @{
*/
#ifndef _CHSCHD_H_
#define _CHSCHD_H_
/**
* @name Wakeup status codes
* @{
*/
#define RDY_OK 0 /**< @brief Normal wakeup message. */
#define RDY_TIMEOUT -1 /**< @brief Wakeup caused by a timeout
condition. */
#define RDY_RESET -2 /**< @brief Wakeup caused by a reset
condition. */
/** @} */
/**
* @name Priority constants
* @{
*/
#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. */
/** @} */
/**
* @name Special time constants
* @{
*/
/**
* @brief Zero time specification for some functions 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)0)
/**
* @brief Infinite time specification for all functions with a timeout
* specification.
*/
#define TIME_INFINITE ((systime_t)-1)
/** @} */
/**
* @brief Returns the priority of the first thread on the given ready list.
*
* @notapi
*/
#define firstprio(rlp) ((rlp)->p_next->p_prio)
/**
* @extends ThreadsQueue
*
* @brief Ready list header.
*/
#if !defined(PORT_OPTIMIZED_READYLIST_STRUCT) || defined(__DOXYGEN__)
typedef struct {
ThreadsQueue r_queue; /**< @brief Threads queue. */
tprio_t r_prio; /**< @brief This field must be
initialized to zero. */
struct context r_ctx; /**< @brief Not used, present because
offsets. */
#if CH_USE_REGISTRY || defined(__DOXYGEN__)
Thread *r_newer; /**< @brief Newer registry element. */
Thread *r_older; /**< @brief Older registry element. */
#endif
/* End of the fields shared with the Thread structure.*/
#if (CH_TIME_QUANTUM > 0) || defined(__DOXYGEN__)
cnt_t r_preempt; /**< @brief Round robin counter. */
#endif
Thread *r_current; /**< @brief The currently running
thread. */
} ReadyList;
#endif /* !defined(PORT_OPTIMIZED_READYLIST_STRUCT) */
#if !defined(PORT_OPTIMIZED_RLIST_EXT) && !defined(__DOXYGEN__)
extern ReadyList rlist;
#endif /* !defined(PORT_OPTIMIZED_RLIST_EXT) */
/**
* @brief Current thread pointer access macro.
* @note This macro is not meant to be used in the application code but
* only from within the kernel, use the @p chThdSelf() API instead.
* @note It is forbidden to use this macro in order to change the pointer
* (currp = something), use @p setcurrp() instead.
*/
#if !defined(PORT_OPTIMIZED_CURRP) || defined(__DOXYGEN__)
#define currp rlist.r_current
#endif /* !defined(PORT_OPTIMIZED_CURRP) */
/**
* @brief Current thread pointer change macro.
* @note This macro is not meant to be used in the application code but
* only from within the kernel.
*
* @notapi
*/
#if !defined(PORT_OPTIMIZED_SETCURRP) || defined(__DOXYGEN__)
#define setcurrp(tp) (currp = (tp))
#endif /* !defined(PORT_OPTIMIZED_SETCURRP) */
/*
* Scheduler APIs.
*/
#ifdef __cplusplus
extern "C" {
#endif
void _scheduler_init(void);
#if !defined(PORT_OPTIMIZED_READYI)
Thread *chSchReadyI(Thread *tp);
#endif
#if !defined(PORT_OPTIMIZED_GOSLEEPS)
void chSchGoSleepS(tstate_t newstate);
#endif
#if !defined(PORT_OPTIMIZED_GOSLEEPTIMEOUTS)
msg_t chSchGoSleepTimeoutS(tstate_t newstate, systime_t time);
#endif
#if !defined(PORT_OPTIMIZED_WAKEUPS)
void chSchWakeupS(Thread *tp, msg_t msg);
#endif
#if !defined(PORT_OPTIMIZED_RESCHEDULES)
void chSchRescheduleS(void);
#endif
#if !defined(PORT_OPTIMIZED_ISPREEMPTIONREQUIRED)
bool_t chSchIsPreemptionRequired(void);
#endif
#if !defined(PORT_OPTIMIZED_DORESCHEDULE)
void chSchDoReschedule(void);
#endif
#ifdef __cplusplus
}
#endif
/**
* @name Macro Functions
* @{
*/
/**
* @brief Determines if the current thread must reschedule.
* @details This function returns @p TRUE if there is a ready thread with
* higher priority.
*
* @iclass
*/
#if !defined(PORT_OPTIMIZED_ISRESCHREQUIREDI) || defined(__DOXYGEN__)
#define chSchIsRescRequiredI() (firstprio(&rlist.r_queue) > currp->p_prio)
#endif /* !defined(PORT_OPTIMIZED_ISRESCHREQUIREDI) */
/**
* @brief Determines if yielding is possible.
* @details This function returns @p TRUE if there is a ready thread with
* equal or higher priority.
*
* @sclass
*/
#if !defined(PORT_OPTIMIZED_CANYIELDS) || defined(__DOXYGEN__)
#define chSchCanYieldS() (firstprio(&rlist.r_queue) >= currp->p_prio)
#endif /* !defined(PORT_OPTIMIZED_CANYIELDS) */
/**
* @brief Yields the time slot.
* @details Yields the CPU control to the next thread in the ready list with
* equal or higher priority, if any.
*
* @sclass
*/
#if !defined(PORT_OPTIMIZED_DOYIELDS) || defined(__DOXYGEN__)
#define chSchDoYieldS() { \
if (chSchCanYieldS()) \
chSchDoReschedule(); \
}
#endif /* !defined(PORT_OPTIMIZED_DOYIELDS) */
/**
* @brief Inlineable preemption code.
* @details This is the common preemption code, this function must be invoked
* exclusively from the port layer.
*
* @special
*/
#if (CH_TIME_QUANTUM > 0) || defined(__DOXYGEN__)
#define chSchPreemption() { \
tprio_t p1 = firstprio(&rlist.r_queue); \
tprio_t p2 = currp->p_prio; \
if (rlist.r_preempt) { \
if (p1 > p2) \
chSchDoReschedule(); \
} \
else { \
if (p1 >= p2) \
chSchDoReschedule(); \
} \
}
#else /* CH_TIME_QUANTUM == 0 */
#define chSchPreemption() { \
if (p1 >= p2) \
chSchDoReschedule(); \
}
#endif /* CH_TIME_QUANTUM == 0 */
/** @} */
#endif /* _CHSCHD_H_ */
/** @} */
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