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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/>.
*/
/**
* @addtogroup Threads
* @{
*/
#include <ch.h>
/*
* Initializes a thread structure.
*/
void _InitThread(t_prio prio, t_tmode mode, Thread *tp) {
static t_tid nextid = 0;
tp->p_tid = nextid++;
tp->p_flags = mode;
tp->p_prio = prio;
tp->p_rdymsg = RDY_OK;
#ifdef CH_USE_RT_SEMAPHORES
tp->p_rtcnt = 0;
#endif
#ifdef CH_USE_WAITEXIT
list_init(&tp->p_waiting);
#endif
#ifdef CH_USE_MESSAGES
fifo_init(&tp->p_msgqueue);
#endif
#ifdef CH_USE_EVENTS
tp->p_epending = 0;
#endif
#ifdef CH_USE_EXIT_EVENT
chEvtInit(&tp->p_exitesource);
#endif
}
/**
* Creates a new thread.
* @param prio the priority level for the new thread. Usually the threads are
* created with priority \p NORMALPRIO (128), priorities
* can range from \p LOWPRIO (1) to \p HIGHPRIO
* (255).
* @param mode the creation option flags for the thread. The following options
* can be OR'ed in this parameter:<br>
* <ul>
* <li>\p P_SUSPENDED, the thread is created in the
* \p PRSUSPENDED state and a subsequent call to
* \p chThdResume() will make it ready for
* execution.</li>
* <li>\p P_TERMINATED, this flag is usually set
* by the \p chThdTerminate() function and it is not
* normally used as parameter for this function. The
* result would be to create a thread with a termination
* request already pending.</li>
* </ul>
* @param workspace pointer to a working area dedicated to the thread stack
* @param wsize size of the working area.
* @param pf the thread function. Returning from this function automatically
* terminates the thread.
* @param arg an argument passed to the thread function. It can be \p NULL.
* @return the pointer to the \p Thread structure allocated for the
* thread into the working space area.
* @note A thread can terminate by calling \p chThdExit() or by simply
* returning from its main function.
*/
Thread *chThdCreate(t_prio prio, t_tmode mode, void *workspace,
t_size wsize, t_tfunc pf, void *arg) {
Thread *tp = workspace;
_InitThread(prio, mode, tp);
SETUP_CONTEXT(workspace, wsize, pf, arg);
#ifdef CH_USE_RESUME
if (tp->p_flags & P_SUSPENDED)
tp->p_state = PRSUSPENDED;
else {
#endif
chSysLock();
chSchWakeupS(tp, RDY_OK);
chSysUnlock();
#ifdef CH_USE_RESUME
}
#endif
return tp;
}
/**
* Changes the thread priority, reschedules if necessary.
* @param newprio the new priority of the invoking thread
*/
void chThdSetPriority(t_prio newprio) {
chSysLock();
#ifdef CH_USE_RT_SEMAPHORES
if (currp->p_rtcnt)
currp->p_prio = newprio + MEPRIO;
else
currp->p_prio = newprio;
#else
currp->p_prio = newprio;
#endif
chSchRescheduleS();
chSysUnlock();
}
#ifdef CH_USE_SUSPEND
/**
* Suspends the invoking thread.
*
* @param tpp pointer to a \p Thread pointer, the \p Thread pointer is set
* to point to the suspended process before it enters the
* \p PRSUSPENDED state, it is set to \p NULL after it is resumed.
* This allows to implement a "test and resume" on the variable
* into interrupt handlers.
* @note The function is available only if the \p CH_USE_SUSPEND
* option is enabled in \p chconf.h.
*/
void chThdSuspend(Thread **tpp) {
chSysLock();
*tpp = currp;
chSchGoSleepS(PRSUSPENDED);
*tpp = NULL;
chSysUnlock();
}
#endif /* CH_USE_SUSPEND */
#ifdef CH_USE_RESUME
/**
* Resumes a thread created with the \p P_SUSPENDED option or suspended with
* \p chThdSuspend().
* @param tp the pointer to the thread
* @note The function has no effect on threads in any other state than
* \p PRSUSPENDED.
* @note The function is available only if the \p CH_USE_RESUME
* option is enabled in \p chconf.h.
*/
void chThdResume(Thread *tp) {
chSysLock();
if ((tp)->p_state == PRSUSPENDED)
chSchWakeupS((tp), RDY_OK);
chSysUnlock();
}
#endif
#ifdef CH_USE_TERMINATE
/**
* Requests a thread termination.
* @param tp the pointer to the thread
* @note The thread is not termitated but a termination request is added to
* its \p p_flags field. The thread can read this status by
* invoking \p chThdShouldTerminate() and then terminate cleanly.
*/
void chThdTerminate(Thread *tp) {
chSysLock();
tp->p_flags |= P_TERMINATE;
chSysUnlock();
}
#endif
/**
* Terminates the current thread by specifying an exit status code.
* @param msg the thread exit code. The code can be retrieved by using
* \p chThdWait().
*/
void chThdExit(t_msg msg) {
chSysLock();
currp->p_exitcode = msg; /* Post mortem info. */
#ifdef CH_USE_WAITEXIT
while (notempty(&currp->p_waiting))
chSchReadyI(list_remove(&currp->p_waiting));
#endif
#ifdef CH_USE_EXIT_EVENT
chEvtSendI(&currp->p_exitesource);
#endif
chSchGoSleepS(PREXIT);
chSysUnlock(); /* Never executed. */
}
#ifdef CH_USE_WAITEXIT
/**
* Blocks the execution of the invoking thread until the specified thread
* terminates then the exit code is returned.
* @param tp the pointer to the thread
* @return the exit code
* @note The function is available only if the \p CH_USE_WAITEXIT
* option is enabled in \p chconf.h.
*/
t_msg chThdWait(Thread *tp) {
chSysLock();
if (tp->p_state != PREXIT) {
list_insert(currp, &tp->p_waiting);
chSchGoSleepS(PRWAIT);
}
chSysUnlock();
return tp->p_exitcode;
}
#endif /* CH_USE_WAITEXIT */
/** @} */
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