523 lines
17 KiB
C
Executable file
523 lines
17 KiB
C
Executable file
/*
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ChibiOS - Copyright (C) 2006..2016 Giovanni Di Sirio.
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This file is part of ChibiOS.
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ChibiOS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file chmboxes.c
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* @brief Mailboxes code.
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*
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* @addtogroup mailboxes
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* @details Asynchronous messages.
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* <h2>Operation mode</h2>
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* A mailbox is an asynchronous communication mechanism.<br>
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* Operations defined for mailboxes:
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* - <b>Post</b>: Posts a message on the mailbox in FIFO order.
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* - <b>Post Ahead</b>: Posts a message on the mailbox with urgent
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* priority.
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* - <b>Fetch</b>: A message is fetched from the mailbox and removed
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* from the queue.
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* - <b>Reset</b>: The mailbox is emptied and all the stored messages
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* are lost.
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* .
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* A message is a variable of type msg_t that is guaranteed to have
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* the same size of and be compatible with (data) pointers (anyway an
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* explicit cast is needed).
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* If larger messages need to be exchanged then a pointer to a
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* structure can be posted in the mailbox but the posting side has
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* no predefined way to know when the message has been processed. A
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* possible approach is to allocate memory (from a memory pool for
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* example) from the posting side and free it on the fetching side.
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* Another approach is to set a "done" flag into the structure pointed
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* by the message.
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* @pre In order to use the mailboxes APIs the @p CH_CFG_USE_MAILBOXES
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* option must be enabled in @p chconf.h.
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* @note Compatible with RT and NIL.
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* @{
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*/
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#include "ch.h"
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#if (CH_CFG_USE_MAILBOXES == TRUE) || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Module exported variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module local types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module local variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module local functions. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module exported functions. */
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/*===========================================================================*/
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/**
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* @brief Initializes a @p mailbox_t object.
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*
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* @param[out] mbp the pointer to the @p mailbox_t structure to be
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* initialized
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* @param[in] buf pointer to the messages buffer as an array of @p msg_t
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* @param[in] n number of elements in the buffer array
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*
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* @init
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*/
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void chMBObjectInit(mailbox_t *mbp, msg_t *buf, cnt_t n) {
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chDbgCheck((mbp != NULL) && (buf != NULL) && (n > (cnt_t)0));
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mbp->buffer = buf;
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mbp->rdptr = buf;
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mbp->wrptr = buf;
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mbp->top = &buf[n];
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mbp->cnt = (cnt_t)0;
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mbp->reset = false;
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chThdQueueObjectInit(&mbp->qw);
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chThdQueueObjectInit(&mbp->qr);
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}
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/**
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* @brief Resets a @p mailbox_t object.
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* @details All the waiting threads are resumed with status @p MSG_RESET and
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* the queued messages are lost.
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* @post The mailbox is in reset state, all operations will fail and
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* return @p MSG reset until the mailbox is enabled again using
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* @p chMBResumeX().
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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*
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* @api
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*/
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void chMBReset(mailbox_t *mbp) {
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chSysLock();
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chMBResetI(mbp);
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chSchRescheduleS();
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chSysUnlock();
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}
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/**
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* @brief Resets a @p mailbox_t object.
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* @details All the waiting threads are resumed with status @p MSG_RESET and
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* the queued messages are lost.
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* @post The mailbox is in reset state, all operations will fail and
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* return @p MSG reset until the mailbox is enabled again using
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* @p chMBResumeX().
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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*
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* @api
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*/
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void chMBResetI(mailbox_t *mbp) {
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chDbgCheckClassI();
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chDbgCheck(mbp != NULL);
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mbp->wrptr = mbp->buffer;
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mbp->rdptr = mbp->buffer;
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mbp->cnt = (cnt_t)0;
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mbp->reset = true;
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chThdDequeueAllI(&mbp->qw, MSG_RESET);
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chThdDequeueAllI(&mbp->qr, MSG_RESET);
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}
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/**
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* @brief Posts a message into a mailbox.
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* @details The invoking thread waits until a empty slot in the mailbox becomes
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* available or the specified time runs out.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[in] msg the message to be posted on the mailbox
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly posted.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the operation has timed out.
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*
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* @api
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*/
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msg_t chMBPost(mailbox_t *mbp, msg_t msg, systime_t timeout) {
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msg_t rdymsg;
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chSysLock();
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rdymsg = chMBPostS(mbp, msg, timeout);
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chSysUnlock();
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return rdymsg;
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}
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/**
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* @brief Posts a message into a mailbox.
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* @details The invoking thread waits until a empty slot in the mailbox becomes
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* available or the specified time runs out.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[in] msg the message to be posted on the mailbox
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly posted.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the operation has timed out.
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*
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* @sclass
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*/
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msg_t chMBPostS(mailbox_t *mbp, msg_t msg, systime_t timeout) {
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msg_t rdymsg;
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chDbgCheckClassS();
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chDbgCheck(mbp != NULL);
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do {
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/* If the mailbox is in reset state then returns immediately.*/
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if (mbp->reset) {
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return MSG_RESET;
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}
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/* Is there a free message slot in queue? if so then post.*/
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if (chMBGetFreeCountI(mbp) > (cnt_t)0) {
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*mbp->wrptr++ = msg;
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if (mbp->wrptr >= mbp->top) {
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mbp->wrptr = mbp->buffer;
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}
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mbp->cnt++;
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/* If there is a reader waiting then makes it ready.*/
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chThdDequeueNextI(&mbp->qr, MSG_OK);
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chSchRescheduleS();
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return MSG_OK;
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}
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/* No space in the queue, waiting for a slot to become available.*/
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rdymsg = chThdEnqueueTimeoutS(&mbp->qw, timeout);
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} while (rdymsg == MSG_OK);
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return rdymsg;
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}
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/**
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* @brief Posts a message into a mailbox.
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* @details This variant is non-blocking, the function returns a timeout
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* condition if the queue is full.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[in] msg the message to be posted on the mailbox
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly posted.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the mailbox is full and the message cannot be
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* posted.
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*
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* @iclass
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*/
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msg_t chMBPostI(mailbox_t *mbp, msg_t msg) {
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chDbgCheckClassI();
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chDbgCheck(mbp != NULL);
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/* If the mailbox is in reset state then returns immediately.*/
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if (mbp->reset) {
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return MSG_RESET;
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}
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/* Is there a free message slot in queue? if so then post.*/
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if (chMBGetFreeCountI(mbp) > (cnt_t)0) {
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*mbp->wrptr++ = msg;
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if (mbp->wrptr >= mbp->top) {
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mbp->wrptr = mbp->buffer;
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}
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mbp->cnt++;
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/* If there is a reader waiting then makes it ready.*/
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chThdDequeueNextI(&mbp->qr, MSG_OK);
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return MSG_OK;
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}
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/* No space, immediate timeout.*/
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return MSG_TIMEOUT;
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}
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/**
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* @brief Posts an high priority message into a mailbox.
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* @details The invoking thread waits until a empty slot in the mailbox becomes
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* available or the specified time runs out.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[in] msg the message to be posted on the mailbox
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly posted.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the operation has timed out.
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*
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* @api
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*/
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msg_t chMBPostAhead(mailbox_t *mbp, msg_t msg, systime_t timeout) {
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msg_t rdymsg;
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chSysLock();
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rdymsg = chMBPostAheadS(mbp, msg, timeout);
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chSysUnlock();
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return rdymsg;
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}
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/**
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* @brief Posts an high priority message into a mailbox.
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* @details The invoking thread waits until a empty slot in the mailbox becomes
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* available or the specified time runs out.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[in] msg the message to be posted on the mailbox
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly posted.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the operation has timed out.
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*
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* @sclass
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*/
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msg_t chMBPostAheadS(mailbox_t *mbp, msg_t msg, systime_t timeout) {
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msg_t rdymsg;
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chDbgCheckClassS();
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chDbgCheck(mbp != NULL);
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do {
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/* If the mailbox is in reset state then returns immediately.*/
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if (mbp->reset) {
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return MSG_RESET;
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}
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/* Is there a free message slot in queue? if so then post.*/
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if (chMBGetFreeCountI(mbp) > (cnt_t)0) {
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if (--mbp->rdptr < mbp->buffer) {
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mbp->rdptr = mbp->top - 1;
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}
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*mbp->rdptr = msg;
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mbp->cnt++;
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/* If there is a reader waiting then makes it ready.*/
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chThdDequeueNextI(&mbp->qr, MSG_OK);
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chSchRescheduleS();
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return MSG_OK;
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}
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/* No space in the queue, waiting for a slot to become available.*/
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rdymsg = chThdEnqueueTimeoutS(&mbp->qw, timeout);
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} while (rdymsg == MSG_OK);
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return rdymsg;
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}
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/**
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* @brief Posts an high priority message into a mailbox.
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* @details This variant is non-blocking, the function returns a timeout
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* condition if the queue is full.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[in] msg the message to be posted on the mailbox
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly posted.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the mailbox is full and the message cannot be
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* posted.
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*
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* @iclass
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*/
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msg_t chMBPostAheadI(mailbox_t *mbp, msg_t msg) {
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chDbgCheckClassI();
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chDbgCheck(mbp != NULL);
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/* If the mailbox is in reset state then returns immediately.*/
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if (mbp->reset) {
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return MSG_RESET;
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}
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/* Is there a free message slot in queue? if so then post.*/
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if (chMBGetFreeCountI(mbp) > (cnt_t)0) {
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if (--mbp->rdptr < mbp->buffer) {
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mbp->rdptr = mbp->top - 1;
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}
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*mbp->rdptr = msg;
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mbp->cnt++;
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/* If there is a reader waiting then makes it ready.*/
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chThdDequeueNextI(&mbp->qr, MSG_OK);
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return MSG_OK;
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}
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/* No space, immediate timeout.*/
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return MSG_TIMEOUT;
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}
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/**
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* @brief Retrieves a message from a mailbox.
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* @details The invoking thread waits until a message is posted in the mailbox
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* or the specified time runs out.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[out] msgp pointer to a message variable for the received message
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly fetched.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the operation has timed out.
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*
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* @api
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*/
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msg_t chMBFetch(mailbox_t *mbp, msg_t *msgp, systime_t timeout) {
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msg_t rdymsg;
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chSysLock();
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rdymsg = chMBFetchS(mbp, msgp, timeout);
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chSysUnlock();
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return rdymsg;
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}
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/**
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* @brief Retrieves a message from a mailbox.
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* @details The invoking thread waits until a message is posted in the mailbox
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* or the specified time runs out.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[out] msgp pointer to a message variable for the received message
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly fetched.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the operation has timed out.
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*
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* @sclass
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*/
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msg_t chMBFetchS(mailbox_t *mbp, msg_t *msgp, systime_t timeout) {
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msg_t rdymsg;
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chDbgCheckClassS();
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chDbgCheck((mbp != NULL) && (msgp != NULL));
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do {
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/* If the mailbox is in reset state then returns immediately.*/
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if (mbp->reset) {
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return MSG_RESET;
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}
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/* Is there a message in queue? if so then fetch.*/
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if (chMBGetUsedCountI(mbp) > (cnt_t)0) {
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*msgp = *mbp->rdptr++;
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if (mbp->rdptr >= mbp->top) {
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mbp->rdptr = mbp->buffer;
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}
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mbp->cnt--;
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/* If there is a writer waiting then makes it ready.*/
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chThdDequeueNextI(&mbp->qw, MSG_OK);
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chSchRescheduleS();
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return MSG_OK;
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}
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/* No message in the queue, waiting for a message to become available.*/
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rdymsg = chThdEnqueueTimeoutS(&mbp->qr, timeout);
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} while (rdymsg == MSG_OK);
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return rdymsg;
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}
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/**
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* @brief Retrieves a message from a mailbox.
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* @details This variant is non-blocking, the function returns a timeout
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* condition if the queue is empty.
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*
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* @param[in] mbp the pointer to an initialized @p mailbox_t object
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* @param[out] msgp pointer to a message variable for the received message
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* @return The operation status.
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* @retval MSG_OK if a message has been correctly fetched.
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* @retval MSG_RESET if the mailbox has been reset.
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* @retval MSG_TIMEOUT if the mailbox is empty and a message cannot be
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* fetched.
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*
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* @iclass
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*/
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msg_t chMBFetchI(mailbox_t *mbp, msg_t *msgp) {
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chDbgCheckClassI();
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chDbgCheck((mbp != NULL) && (msgp != NULL));
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/* If the mailbox is in reset state then returns immediately.*/
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if (mbp->reset) {
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return MSG_RESET;
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}
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/* Is there a message in queue? if so then fetch.*/
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if (chMBGetUsedCountI(mbp) > (cnt_t)0) {
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*msgp = *mbp->rdptr++;
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if (mbp->rdptr >= mbp->top) {
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mbp->rdptr = mbp->buffer;
|
|
}
|
|
mbp->cnt--;
|
|
|
|
/* If there is a writer waiting then makes it ready.*/
|
|
chThdDequeueNextI(&mbp->qw, MSG_OK);
|
|
|
|
return MSG_OK;
|
|
}
|
|
|
|
/* No message, immediate timeout.*/
|
|
return MSG_TIMEOUT;
|
|
}
|
|
#endif /* CH_CFG_USE_MAILBOXES == TRUE */
|
|
|
|
/** @} */
|