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<td><big><big>ChibiOS/RT</big></big><br><br>Architecture - Reference Manual - Guides</td>
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<h1>chsem.c</h1> </div>
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<a href="chsem_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*</span>
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<a name="l00002"></a>00002 <span class="comment"> ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 Giovanni Di Sirio.</span>
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<a name="l00003"></a>00003 <span class="comment"></span>
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<a name="l00004"></a>00004 <span class="comment"> This file is part of ChibiOS/RT.</span>
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<a name="l00005"></a>00005 <span class="comment"></span>
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<a name="l00006"></a>00006 <span class="comment"> ChibiOS/RT is free software; you can redistribute it and/or modify</span>
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<a name="l00007"></a>00007 <span class="comment"> it under the terms of the GNU General Public License as published by</span>
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<a name="l00008"></a>00008 <span class="comment"> the Free Software Foundation; either version 3 of the License, or</span>
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<a name="l00009"></a>00009 <span class="comment"> (at your option) any later version.</span>
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<a name="l00010"></a>00010 <span class="comment"></span>
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<a name="l00011"></a>00011 <span class="comment"> ChibiOS/RT is distributed in the hope that it will be useful,</span>
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<a name="l00012"></a>00012 <span class="comment"> but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
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<a name="l00013"></a>00013 <span class="comment"> MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span>
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<a name="l00014"></a>00014 <span class="comment"> GNU General Public License for more details.</span>
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<a name="l00015"></a>00015 <span class="comment"></span>
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<a name="l00016"></a>00016 <span class="comment"> You should have received a copy of the GNU General Public License</span>
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<a name="l00017"></a>00017 <span class="comment"> along with this program. If not, see <http://www.gnu.org/licenses/>.</span>
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<a name="l00018"></a>00018 <span class="comment"></span>
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<a name="l00019"></a>00019 <span class="comment"> ---</span>
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<a name="l00020"></a>00020 <span class="comment"></span>
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<a name="l00021"></a>00021 <span class="comment"> A special exception to the GPL can be applied should you wish to distribute</span>
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<a name="l00022"></a>00022 <span class="comment"> a combined work that includes ChibiOS/RT, without being obliged to provide</span>
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<a name="l00023"></a>00023 <span class="comment"> the source code for any proprietary components. See the file exception.txt</span>
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<a name="l00024"></a>00024 <span class="comment"> for full details of how and when the exception can be applied.</span>
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<a name="l00025"></a>00025 <span class="comment">*/</span>
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<a name="l00026"></a>00026 <span class="comment"></span>
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<a name="l00027"></a>00027 <span class="comment">/**</span>
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<a name="l00028"></a>00028 <span class="comment"> * @file chsem.c</span>
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<a name="l00029"></a>00029 <span class="comment"> * @brief Semaphores code.</span>
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<a name="l00030"></a>00030 <span class="comment"> *</span>
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<a name="l00031"></a>00031 <span class="comment"> * @addtogroup semaphores</span>
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<a name="l00032"></a>00032 <span class="comment"> * @details Semaphores related APIs and services.</span>
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<a name="l00033"></a>00033 <span class="comment"> *</span>
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<a name="l00034"></a>00034 <span class="comment"> * <h2>Operation mode</h2></span>
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<a name="l00035"></a>00035 <span class="comment"> * Semaphores are a flexible synchronization primitive, ChibiOS/RT</span>
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<a name="l00036"></a>00036 <span class="comment"> * implements semaphores in their "counting semaphores" variant as</span>
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<a name="l00037"></a>00037 <span class="comment"> * defined by Edsger Dijkstra plus several enhancements like:</span>
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<a name="l00038"></a>00038 <span class="comment"> * - Wait operation with timeout.</span>
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<a name="l00039"></a>00039 <span class="comment"> * - Reset operation.</span>
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<a name="l00040"></a>00040 <span class="comment"> * - Atomic wait+signal operation.</span>
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<a name="l00041"></a>00041 <span class="comment"> * - Return message from the wait operation (OK, RESET, TIMEOUT).</span>
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<a name="l00042"></a>00042 <span class="comment"> * .</span>
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<a name="l00043"></a>00043 <span class="comment"> * The binary semaphores variant can be easily implemented using</span>
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<a name="l00044"></a>00044 <span class="comment"> * counting semaphores.<br></span>
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<a name="l00045"></a>00045 <span class="comment"> * Operations defined for semaphores:</span>
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<a name="l00046"></a>00046 <span class="comment"> * - <b>Signal</b>: The semaphore counter is increased and if the</span>
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<a name="l00047"></a>00047 <span class="comment"> * result is non-positive then a waiting thread is removed from</span>
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<a name="l00048"></a>00048 <span class="comment"> * the semaphore queue and made ready for execution.</span>
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<a name="l00049"></a>00049 <span class="comment"> * - <b>Wait</b>: The semaphore counter is decreased and if the result</span>
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<a name="l00050"></a>00050 <span class="comment"> * becomes negative the thread is queued in the semaphore and</span>
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<a name="l00051"></a>00051 <span class="comment"> * suspended.</span>
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<a name="l00052"></a>00052 <span class="comment"> * - <b>Reset</b>: The semaphore counter is reset to a non-negative</span>
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<a name="l00053"></a>00053 <span class="comment"> * value and all the threads in the queue are released.</span>
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<a name="l00054"></a>00054 <span class="comment"> * .</span>
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<a name="l00055"></a>00055 <span class="comment"> * Semaphores can be used as guards for mutual exclusion zones</span>
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<a name="l00056"></a>00056 <span class="comment"> * (note that mutexes are recommended for this kind of use) but</span>
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<a name="l00057"></a>00057 <span class="comment"> * also have other uses, queues guards and counters as example.<br></span>
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<a name="l00058"></a>00058 <span class="comment"> * Semaphores usually use a FIFO queuing strategy but it is possible</span>
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<a name="l00059"></a>00059 <span class="comment"> * to make them order threads by priority by enabling</span>
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<a name="l00060"></a>00060 <span class="comment"> * @p CH_USE_SEMAPHORES_PRIORITY in @p chconf.h.<br></span>
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<a name="l00061"></a>00061 <span class="comment"> * In order to use the Semaphores APIs the @p CH_USE_SEMAPHORES</span>
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<a name="l00062"></a>00062 <span class="comment"> * option must be enabled in @p chconf.h.</span>
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<a name="l00063"></a>00063 <span class="comment"> * @{</span>
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<a name="l00064"></a>00064 <span class="comment"> */</span>
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<a name="l00065"></a>00065
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<a name="l00066"></a>00066 <span class="preprocessor">#include "<a class="code" href="ch_8h.html" title="ChibiOS/RT main include file.">ch.h</a>"</span>
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<a name="l00067"></a>00067
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<a name="l00068"></a>00068 <span class="preprocessor">#if CH_USE_SEMAPHORES</span>
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<a name="l00069"></a>00069 <span class="preprocessor"></span>
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<a name="l00070"></a>00070 <span class="preprocessor">#if CH_USE_SEMAPHORES_PRIORITY</span>
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<a name="l00071"></a>00071 <span class="preprocessor"></span><span class="preprocessor">#define sem_insert(tp, qp) prio_insert(tp, qp)</span>
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<a name="l00072"></a>00072 <span class="preprocessor"></span><span class="preprocessor">#else</span>
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<a name="l00073"></a>00073 <span class="preprocessor"></span><span class="preprocessor">#define sem_insert(tp, qp) queue_insert(tp, qp)</span>
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<a name="l00074"></a>00074 <span class="preprocessor"></span><span class="preprocessor">#endif</span>
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<a name="l00075"></a>00075 <span class="preprocessor"></span><span class="comment"></span>
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<a name="l00076"></a>00076 <span class="comment">/**</span>
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<a name="l00077"></a>00077 <span class="comment"> * @brief Initializes a semaphore with the specified counter value.</span>
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<a name="l00078"></a>00078 <span class="comment"> *</span>
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<a name="l00079"></a>00079 <span class="comment"> * @param[out] sp pointer to a @p Semaphore structure</span>
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<a name="l00080"></a>00080 <span class="comment"> * @param[in] n initial value of the semaphore counter. Must be</span>
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<a name="l00081"></a>00081 <span class="comment"> * non-negative.</span>
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<a name="l00082"></a>00082 <span class="comment"> */</span>
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<a name="l00083"></a><a class="code" href="group__semaphores.html#gafe8fc6155a871074e8017efd908b2c58">00083</a> <span class="keywordtype">void</span> <a class="code" href="group__semaphores.html#gafe8fc6155a871074e8017efd908b2c58" title="Initializes a semaphore with the specified counter value.">chSemInit</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp, <a class="code" href="group__types.html#ga090b3bab5602157ebf706a44041dc05e" title="Counter, recommended fastest signed.">cnt_t</a> n) {
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<a name="l00084"></a>00084
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<a name="l00085"></a>00085 <a class="code" href="group__debug.html#ga6bb6c0f97caab3a66332c8bfbf7a3844" title="Function parameter check.">chDbgCheck</a>((sp != NULL) && (n >= 0), <span class="stringliteral">"chSemInit"</span>);
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<a name="l00086"></a>00086
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<a name="l00087"></a>00087 <a class="code" href="group__internals.html#ga6d19d0f3ff1fa599b6d9783dec180451" title="Threads queue initialization.">queue_init</a>(&sp-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>);
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<a name="l00088"></a>00088 sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> = n;
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<a name="l00089"></a>00089 }
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<a name="l00090"></a>00090 <span class="comment"></span>
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<a name="l00091"></a>00091 <span class="comment">/**</span>
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<a name="l00092"></a>00092 <span class="comment"> * @brief Performs a reset operation on the semaphore.</span>
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<a name="l00093"></a>00093 <span class="comment"> * @note The released threads can recognize they were waked up by a reset</span>
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<a name="l00094"></a>00094 <span class="comment"> * rather than a signal because the @p chSemWait() will return</span>
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<a name="l00095"></a>00095 <span class="comment"> * @p RDY_RESET instead of @p RDY_OK.</span>
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<a name="l00096"></a>00096 <span class="comment"> *</span>
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<a name="l00097"></a>00097 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
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<a name="l00098"></a>00098 <span class="comment"> * @param[in] n the new value of the semaphore counter. The value must</span>
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<a name="l00099"></a>00099 <span class="comment"> * be non-negative.</span>
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<a name="l00100"></a>00100 <span class="comment"> */</span>
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<a name="l00101"></a><a class="code" href="group__semaphores.html#ga58e266e609cfd3dbc67f299b3ae9debb">00101</a> <span class="keywordtype">void</span> <a class="code" href="group__semaphores.html#ga58e266e609cfd3dbc67f299b3ae9debb" title="Performs a reset operation on the semaphore.">chSemReset</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp, <a class="code" href="group__types.html#ga090b3bab5602157ebf706a44041dc05e" title="Counter, recommended fastest signed.">cnt_t</a> n) {
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<a name="l00102"></a>00102
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<a name="l00103"></a>00103 <a class="code" href="group__system.html#ga9f6573c0763d1e4e97c63c62edad6e42" title="Enters the kernel lock mode.">chSysLock</a>();
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<a name="l00104"></a>00104 <a class="code" href="group__semaphores.html#gae7972b6b22b80ac09bac5a186277ab81" title="Performs a reset operation on the semaphore.">chSemResetI</a>(sp, n);
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<a name="l00105"></a>00105 <a class="code" href="group__scheduler.html#ga4e38b4bee3d2330f6a0f1cdb7660af20" title="Performs a reschedule if a higher priority thread is runnable.">chSchRescheduleS</a>();
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<a name="l00106"></a>00106 <a class="code" href="group__system.html#ga5a257fa58a09815eb64a45e2dfbdc22e" title="Leaves the kernel lock mode.">chSysUnlock</a>();
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<a name="l00107"></a>00107 }
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<a name="l00108"></a>00108 <span class="comment"></span>
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<a name="l00109"></a>00109 <span class="comment">/**</span>
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<a name="l00110"></a>00110 <span class="comment"> * @brief Performs a reset operation on the semaphore.</span>
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<a name="l00111"></a>00111 <span class="comment"> * @note The released threads can recognize they were waked up by a reset</span>
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<a name="l00112"></a>00112 <span class="comment"> * rather than a signal because the @p chSemWait() will return</span>
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<a name="l00113"></a>00113 <span class="comment"> * @p RDY_RESET instead of @p RDY_OK.</span>
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<a name="l00114"></a>00114 <span class="comment"> * @note This function does not reschedule.</span>
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<a name="l00115"></a>00115 <span class="comment"> *</span>
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<a name="l00116"></a>00116 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
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<a name="l00117"></a>00117 <span class="comment"> * @param[in] n the new value of the semaphore counter. The value must</span>
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<a name="l00118"></a>00118 <span class="comment"> * be non-negative.</span>
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<a name="l00119"></a>00119 <span class="comment"> */</span>
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<a name="l00120"></a><a class="code" href="group__semaphores.html#gae7972b6b22b80ac09bac5a186277ab81">00120</a> <span class="keywordtype">void</span> <a class="code" href="group__semaphores.html#gae7972b6b22b80ac09bac5a186277ab81" title="Performs a reset operation on the semaphore.">chSemResetI</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp, <a class="code" href="group__types.html#ga090b3bab5602157ebf706a44041dc05e" title="Counter, recommended fastest signed.">cnt_t</a> n) {
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<a name="l00121"></a>00121 <a class="code" href="group__types.html#ga090b3bab5602157ebf706a44041dc05e" title="Counter, recommended fastest signed.">cnt_t</a> cnt;
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<a name="l00122"></a>00122
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<a name="l00123"></a>00123 <a class="code" href="group__debug.html#ga6bb6c0f97caab3a66332c8bfbf7a3844" title="Function parameter check.">chDbgCheck</a>((sp != NULL) && (n >= 0), <span class="stringliteral">"chSemResetI"</span>);
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<a name="l00124"></a>00124
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<a name="l00125"></a>00125 cnt = sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a>;
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<a name="l00126"></a>00126 sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> = n;
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<a name="l00127"></a>00127 <span class="keywordflow">while</span> (++cnt <= 0)
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<a name="l00128"></a>00128 <a class="code" href="group__scheduler.html#ga535d58cfb3436c8d4e4586c31c062298" title="Inserts a thread in the Ready List.">chSchReadyI</a>(<a class="code" href="group__internals.html#gacacfe77140cab62948e63d898bf4dfba" title="Removes the last-out Thread from a queue and returns it.">lifo_remove</a>(&sp-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>))-><a class="code" href="struct_thread.html#a72cd0424b6098ca241fac1f74d21b56a" title="State-specific fields.">p_u</a>.<a class="code" href="struct_thread.html#ad5792c30fbd60df0de223b0f398fc6d7" title="Thread wakeup code.">rdymsg</a> = RDY_RESET;
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<a name="l00129"></a>00129 }
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<a name="l00130"></a>00130 <span class="comment"></span>
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<a name="l00131"></a>00131 <span class="comment">/**</span>
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<a name="l00132"></a>00132 <span class="comment"> * @brief Performs a wait operation on a semaphore.</span>
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<a name="l00133"></a>00133 <span class="comment"> *</span>
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<a name="l00134"></a>00134 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
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<a name="l00135"></a>00135 <span class="comment"> * @retval RDY_OK if the semaphore was signaled or not taken.</span>
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<a name="l00136"></a>00136 <span class="comment"> * @retval RDY_RESET if the semaphore was reset using @p chSemReset().</span>
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<a name="l00137"></a>00137 <span class="comment"> */</span>
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<a name="l00138"></a><a class="code" href="group__semaphores.html#gabc8f7e509870e9b0527a6a68fad71425">00138</a> <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> <a class="code" href="group__semaphores.html#gabc8f7e509870e9b0527a6a68fad71425" title="Performs a wait operation on a semaphore.">chSemWait</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp) {
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<a name="l00139"></a>00139 <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> msg;
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<a name="l00140"></a>00140
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<a name="l00141"></a>00141 <a class="code" href="group__system.html#ga9f6573c0763d1e4e97c63c62edad6e42" title="Enters the kernel lock mode.">chSysLock</a>();
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<a name="l00142"></a>00142 msg = <a class="code" href="group__semaphores.html#gaa2c0367078533e291d2e889e251d8b67" title="Performs a wait operation on a semaphore.">chSemWaitS</a>(sp);
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<a name="l00143"></a>00143 <a class="code" href="group__system.html#ga5a257fa58a09815eb64a45e2dfbdc22e" title="Leaves the kernel lock mode.">chSysUnlock</a>();
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<a name="l00144"></a>00144 <span class="keywordflow">return</span> msg;
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<a name="l00145"></a>00145 }
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<a name="l00146"></a>00146 <span class="comment"></span>
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<a name="l00147"></a>00147 <span class="comment">/**</span>
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<a name="l00148"></a>00148 <span class="comment"> * @brief Performs a wait operation on a semaphore.</span>
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<a name="l00149"></a>00149 <span class="comment"> *</span>
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<a name="l00150"></a>00150 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
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<a name="l00151"></a>00151 <span class="comment"> * @retval RDY_OK if the semaphore was signaled or not taken.</span>
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<a name="l00152"></a>00152 <span class="comment"> * @retval RDY_RESET if the semaphore was reset using @p chSemReset().</span>
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<a name="l00153"></a>00153 <span class="comment"> */</span>
|
|
<a name="l00154"></a><a class="code" href="group__semaphores.html#gaa2c0367078533e291d2e889e251d8b67">00154</a> <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> <a class="code" href="group__semaphores.html#gaa2c0367078533e291d2e889e251d8b67" title="Performs a wait operation on a semaphore.">chSemWaitS</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp) {
|
|
<a name="l00155"></a>00155
|
|
<a name="l00156"></a>00156 <a class="code" href="group__debug.html#ga6bb6c0f97caab3a66332c8bfbf7a3844" title="Function parameter check.">chDbgCheck</a>(sp != NULL, <span class="stringliteral">"chSemWaitS"</span>);
|
|
<a name="l00157"></a>00157
|
|
<a name="l00158"></a>00158 <span class="keywordflow">if</span> (--sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> < 0) {
|
|
<a name="l00159"></a>00159 <a class="code" href="group__scheduler.html#ga1a5fddde56420e8accd0c09c1abb32a7" title="Current thread pointer access macro.">currp</a>->p_u.wtobjp = sp;
|
|
<a name="l00160"></a>00160 sem_insert(<a class="code" href="group__scheduler.html#ga1a5fddde56420e8accd0c09c1abb32a7" title="Current thread pointer access macro.">currp</a>, &sp-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>);
|
|
<a name="l00161"></a>00161 <a class="code" href="group__scheduler.html#ga97c1c514b755a1e71caf2f19c1ccf986" title="Puts the current thread to sleep into the specified state.">chSchGoSleepS</a>(<a class="code" href="group__threads.html#gad0b81cae859c0a6bc6a0d2036aa8e272" title="Thread state: Waiting on a semaphore.">THD_STATE_WTSEM</a>);
|
|
<a name="l00162"></a>00162 <span class="keywordflow">return</span> <a class="code" href="group__scheduler.html#ga1a5fddde56420e8accd0c09c1abb32a7" title="Current thread pointer access macro.">currp</a>->p_u.rdymsg;
|
|
<a name="l00163"></a>00163 }
|
|
<a name="l00164"></a>00164 <span class="keywordflow">return</span> RDY_OK;
|
|
<a name="l00165"></a>00165 }
|
|
<a name="l00166"></a>00166 <span class="comment"></span>
|
|
<a name="l00167"></a>00167 <span class="comment">/**</span>
|
|
<a name="l00168"></a>00168 <span class="comment"> * @brief Performs a wait operation on a semaphore with timeout specification.</span>
|
|
<a name="l00169"></a>00169 <span class="comment"> *</span>
|
|
<a name="l00170"></a>00170 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
|
|
<a name="l00171"></a>00171 <span class="comment"> * @param[in] time the number of ticks before the operation timeouts,</span>
|
|
<a name="l00172"></a>00172 <span class="comment"> * the following special values are allowed:</span>
|
|
<a name="l00173"></a>00173 <span class="comment"> * - @a TIME_IMMEDIATE immediate timeout.</span>
|
|
<a name="l00174"></a>00174 <span class="comment"> * - @a TIME_INFINITE no timeout.</span>
|
|
<a name="l00175"></a>00175 <span class="comment"> * .</span>
|
|
<a name="l00176"></a>00176 <span class="comment"> * @retval RDY_OK if the semaphore was signaled or not taken.</span>
|
|
<a name="l00177"></a>00177 <span class="comment"> * @retval RDY_RESET if the semaphore was reset using @p chSemReset().</span>
|
|
<a name="l00178"></a>00178 <span class="comment"> * @retval RDY_TIMEOUT if the semaphore was not signaled or reset within the</span>
|
|
<a name="l00179"></a>00179 <span class="comment"> * specified timeout.</span>
|
|
<a name="l00180"></a>00180 <span class="comment"> */</span>
|
|
<a name="l00181"></a><a class="code" href="group__semaphores.html#ga0bc227311e5be3e3b6e3aee6a68169da">00181</a> <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> <a class="code" href="group__semaphores.html#ga0bc227311e5be3e3b6e3aee6a68169da" title="Performs a wait operation on a semaphore with timeout specification.">chSemWaitTimeout</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp, <a class="code" href="group__types.html#gae3e32a98d431a02106616da3071832dd" title="System Time, recommended fastest unsigned.">systime_t</a> time) {
|
|
<a name="l00182"></a>00182 <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> msg;
|
|
<a name="l00183"></a>00183
|
|
<a name="l00184"></a>00184 <a class="code" href="group__system.html#ga9f6573c0763d1e4e97c63c62edad6e42" title="Enters the kernel lock mode.">chSysLock</a>();
|
|
<a name="l00185"></a>00185 msg = <a class="code" href="group__semaphores.html#ga924ec5d191bb8debe8727ae4dd5d6d03" title="Performs a wait operation on a semaphore with timeout specification.">chSemWaitTimeoutS</a>(sp, time);
|
|
<a name="l00186"></a>00186 <a class="code" href="group__system.html#ga5a257fa58a09815eb64a45e2dfbdc22e" title="Leaves the kernel lock mode.">chSysUnlock</a>();
|
|
<a name="l00187"></a>00187 <span class="keywordflow">return</span> msg;
|
|
<a name="l00188"></a>00188 }
|
|
<a name="l00189"></a>00189 <span class="comment"></span>
|
|
<a name="l00190"></a>00190 <span class="comment">/**</span>
|
|
<a name="l00191"></a>00191 <span class="comment"> * @brief Performs a wait operation on a semaphore with timeout specification.</span>
|
|
<a name="l00192"></a>00192 <span class="comment"> *</span>
|
|
<a name="l00193"></a>00193 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
|
|
<a name="l00194"></a>00194 <span class="comment"> * @param[in] time the number of ticks before the operation timeouts,</span>
|
|
<a name="l00195"></a>00195 <span class="comment"> * the following special values are allowed:</span>
|
|
<a name="l00196"></a>00196 <span class="comment"> * - @a TIME_IMMEDIATE immediate timeout.</span>
|
|
<a name="l00197"></a>00197 <span class="comment"> * - @a TIME_INFINITE no timeout.</span>
|
|
<a name="l00198"></a>00198 <span class="comment"> * .</span>
|
|
<a name="l00199"></a>00199 <span class="comment"> * @retval RDY_OK if the semaphore was signaled or not taken.</span>
|
|
<a name="l00200"></a>00200 <span class="comment"> * @retval RDY_RESET if the semaphore was reset using @p chSemReset().</span>
|
|
<a name="l00201"></a>00201 <span class="comment"> * @retval RDY_TIMEOUT if the semaphore was not signaled or reset within the</span>
|
|
<a name="l00202"></a>00202 <span class="comment"> * specified timeout.</span>
|
|
<a name="l00203"></a>00203 <span class="comment"> */</span>
|
|
<a name="l00204"></a><a class="code" href="group__semaphores.html#ga924ec5d191bb8debe8727ae4dd5d6d03">00204</a> <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> <a class="code" href="group__semaphores.html#ga924ec5d191bb8debe8727ae4dd5d6d03" title="Performs a wait operation on a semaphore with timeout specification.">chSemWaitTimeoutS</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp, <a class="code" href="group__types.html#gae3e32a98d431a02106616da3071832dd" title="System Time, recommended fastest unsigned.">systime_t</a> time) {
|
|
<a name="l00205"></a>00205
|
|
<a name="l00206"></a>00206 <a class="code" href="group__debug.html#ga6bb6c0f97caab3a66332c8bfbf7a3844" title="Function parameter check.">chDbgCheck</a>(sp != NULL, <span class="stringliteral">"chSemWaitTimeoutS"</span>);
|
|
<a name="l00207"></a>00207
|
|
<a name="l00208"></a>00208 <span class="keywordflow">if</span> (--sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> < 0) {
|
|
<a name="l00209"></a>00209 <span class="keywordflow">if</span> (<a class="code" href="group__scheduler.html#gad1ac15e9e5fc17810a94a779257f3d29" title="Zero time specification for some syscalls with a timeout specification.">TIME_IMMEDIATE</a> == time) {
|
|
<a name="l00210"></a>00210 sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a>++;
|
|
<a name="l00211"></a>00211 <span class="keywordflow">return</span> RDY_TIMEOUT;
|
|
<a name="l00212"></a>00212 }
|
|
<a name="l00213"></a>00213 <a class="code" href="group__scheduler.html#ga1a5fddde56420e8accd0c09c1abb32a7" title="Current thread pointer access macro.">currp</a>->p_u.wtobjp = sp;
|
|
<a name="l00214"></a>00214 sem_insert(<a class="code" href="group__scheduler.html#ga1a5fddde56420e8accd0c09c1abb32a7" title="Current thread pointer access macro.">currp</a>, &sp-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>);
|
|
<a name="l00215"></a>00215 <span class="keywordflow">return</span> <a class="code" href="group__scheduler.html#ga306e564f678c1a39139639490c77e78b" title="Puts the current thread to sleep into the specified state with timeout specification.">chSchGoSleepTimeoutS</a>(<a class="code" href="group__threads.html#gad0b81cae859c0a6bc6a0d2036aa8e272" title="Thread state: Waiting on a semaphore.">THD_STATE_WTSEM</a>, time);
|
|
<a name="l00216"></a>00216 }
|
|
<a name="l00217"></a>00217 <span class="keywordflow">return</span> RDY_OK;
|
|
<a name="l00218"></a>00218 }
|
|
<a name="l00219"></a>00219 <span class="comment"></span>
|
|
<a name="l00220"></a>00220 <span class="comment">/**</span>
|
|
<a name="l00221"></a>00221 <span class="comment"> * @brief Performs a signal operation on a semaphore.</span>
|
|
<a name="l00222"></a>00222 <span class="comment"> *</span>
|
|
<a name="l00223"></a>00223 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
|
|
<a name="l00224"></a>00224 <span class="comment"> */</span>
|
|
<a name="l00225"></a><a class="code" href="group__semaphores.html#ga7ec0cbda23e49e2370e0b91f20baf05e">00225</a> <span class="keywordtype">void</span> <a class="code" href="group__semaphores.html#ga7ec0cbda23e49e2370e0b91f20baf05e" title="Performs a signal operation on a semaphore.">chSemSignal</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp) {
|
|
<a name="l00226"></a>00226
|
|
<a name="l00227"></a>00227 <a class="code" href="group__debug.html#ga6bb6c0f97caab3a66332c8bfbf7a3844" title="Function parameter check.">chDbgCheck</a>(sp != NULL, <span class="stringliteral">"chSemSignal"</span>);
|
|
<a name="l00228"></a>00228
|
|
<a name="l00229"></a>00229 <a class="code" href="group__system.html#ga9f6573c0763d1e4e97c63c62edad6e42" title="Enters the kernel lock mode.">chSysLock</a>();
|
|
<a name="l00230"></a>00230 <span class="keywordflow">if</span> (++sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> <= 0)
|
|
<a name="l00231"></a>00231 <a class="code" href="group__scheduler.html#gae47a8819a21ef2d521124e76bfb37c95" title="Wakes up a thread.">chSchWakeupS</a>(<a class="code" href="group__internals.html#ga042479f09357fc59befebf4dfe0e9f4a" title="Removes the first-out Thread from a queue and returns it.">fifo_remove</a>(&sp-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>), <a class="code" href="group__scheduler.html#gae1c86078318e11c2fa57ee3c2ec69f61" title="Default thread wakeup low level message.">RDY_OK</a>);
|
|
<a name="l00232"></a>00232 <a class="code" href="group__system.html#ga5a257fa58a09815eb64a45e2dfbdc22e" title="Leaves the kernel lock mode.">chSysUnlock</a>();
|
|
<a name="l00233"></a>00233 }
|
|
<a name="l00234"></a>00234 <span class="comment"></span>
|
|
<a name="l00235"></a>00235 <span class="comment">/**</span>
|
|
<a name="l00236"></a>00236 <span class="comment"> * @brief Performs a signal operation on a semaphore.</span>
|
|
<a name="l00237"></a>00237 <span class="comment"> * @note This function does not reschedule.</span>
|
|
<a name="l00238"></a>00238 <span class="comment"> *</span>
|
|
<a name="l00239"></a>00239 <span class="comment"> * @param[in] sp pointer to a @p Semaphore structure</span>
|
|
<a name="l00240"></a>00240 <span class="comment"> */</span>
|
|
<a name="l00241"></a><a class="code" href="group__semaphores.html#gaca0b70cf495a9cb7569e1cf5b07e2b3d">00241</a> <span class="keywordtype">void</span> <a class="code" href="group__semaphores.html#gaca0b70cf495a9cb7569e1cf5b07e2b3d" title="Performs a signal operation on a semaphore.">chSemSignalI</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sp) {
|
|
<a name="l00242"></a>00242
|
|
<a name="l00243"></a>00243 <a class="code" href="group__debug.html#ga6bb6c0f97caab3a66332c8bfbf7a3844" title="Function parameter check.">chDbgCheck</a>(sp != NULL, <span class="stringliteral">"chSemSignalI"</span>);
|
|
<a name="l00244"></a>00244
|
|
<a name="l00245"></a>00245 <span class="keywordflow">if</span> (++sp-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> <= 0) {
|
|
<a name="l00246"></a>00246 <span class="comment">/* note, it is done this way in order to allow a tail call on</span>
|
|
<a name="l00247"></a>00247 <span class="comment"> chSchReadyI().*/</span>
|
|
<a name="l00248"></a>00248 <a class="code" href="struct_thread.html" title="Structure representing a thread.">Thread</a> *tp = <a class="code" href="group__internals.html#ga042479f09357fc59befebf4dfe0e9f4a" title="Removes the first-out Thread from a queue and returns it.">fifo_remove</a>(&sp-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>);
|
|
<a name="l00249"></a>00249 tp-><a class="code" href="struct_thread.html#a72cd0424b6098ca241fac1f74d21b56a" title="State-specific fields.">p_u</a>.<a class="code" href="struct_thread.html#ad5792c30fbd60df0de223b0f398fc6d7" title="Thread wakeup code.">rdymsg</a> = RDY_OK;
|
|
<a name="l00250"></a>00250 <a class="code" href="group__scheduler.html#ga535d58cfb3436c8d4e4586c31c062298" title="Inserts a thread in the Ready List.">chSchReadyI</a>(tp);
|
|
<a name="l00251"></a>00251 }
|
|
<a name="l00252"></a>00252 }
|
|
<a name="l00253"></a>00253
|
|
<a name="l00254"></a>00254 <span class="preprocessor">#if CH_USE_SEMSW</span>
|
|
<a name="l00255"></a>00255 <span class="preprocessor"></span><span class="comment">/**</span>
|
|
<a name="l00256"></a>00256 <span class="comment"> * @brief Performs atomic signal and wait operations on two semaphores.</span>
|
|
<a name="l00257"></a>00257 <span class="comment"> * @note The function is available only if the @p CH_USE_SEMSW</span>
|
|
<a name="l00258"></a>00258 <span class="comment"> * option is enabled in @p chconf.h.</span>
|
|
<a name="l00259"></a>00259 <span class="comment"> *</span>
|
|
<a name="l00260"></a>00260 <span class="comment"> * @param[in] sps pointer to a @p Semaphore structure to be signaled</span>
|
|
<a name="l00261"></a>00261 <span class="comment"> * @param[in] spw pointer to a @p Semaphore structure to be wait on</span>
|
|
<a name="l00262"></a>00262 <span class="comment"> * @retval RDY_OK if the semaphore was signaled or not taken.</span>
|
|
<a name="l00263"></a>00263 <span class="comment"> * @retval RDY_RESET if the semaphore was reset using @p chSemReset().</span>
|
|
<a name="l00264"></a>00264 <span class="comment"> */</span>
|
|
<a name="l00265"></a><a class="code" href="group__semaphores.html#ga0dc7b4339506de346d67b4560b271e44">00265</a> <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> <a class="code" href="group__semaphores.html#ga0dc7b4339506de346d67b4560b271e44" title="Performs atomic signal and wait operations on two semaphores.">chSemSignalWait</a>(<a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *sps, <a class="code" href="struct_semaphore.html" title="Semaphore structure.">Semaphore</a> *spw) {
|
|
<a name="l00266"></a>00266 <a class="code" href="group__types.html#ga35bcb0c321cd7bc45bf1a11fa17ebdd3" title="Message, use signed pointer equivalent.">msg_t</a> msg;
|
|
<a name="l00267"></a>00267
|
|
<a name="l00268"></a>00268 <a class="code" href="group__debug.html#ga6bb6c0f97caab3a66332c8bfbf7a3844" title="Function parameter check.">chDbgCheck</a>((sps != NULL) && (spw != NULL), <span class="stringliteral">"chSemSignalWait"</span>);
|
|
<a name="l00269"></a>00269
|
|
<a name="l00270"></a>00270 <a class="code" href="group__system.html#ga9f6573c0763d1e4e97c63c62edad6e42" title="Enters the kernel lock mode.">chSysLock</a>();
|
|
<a name="l00271"></a>00271 <span class="keywordflow">if</span> (++sps-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> <= 0)
|
|
<a name="l00272"></a>00272 <a class="code" href="group__scheduler.html#ga535d58cfb3436c8d4e4586c31c062298" title="Inserts a thread in the Ready List.">chSchReadyI</a>(<a class="code" href="group__internals.html#ga042479f09357fc59befebf4dfe0e9f4a" title="Removes the first-out Thread from a queue and returns it.">fifo_remove</a>(&sps-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>))-><a class="code" href="struct_thread.html#a72cd0424b6098ca241fac1f74d21b56a" title="State-specific fields.">p_u</a>.<a class="code" href="struct_thread.html#ad5792c30fbd60df0de223b0f398fc6d7" title="Thread wakeup code.">rdymsg</a> = RDY_OK;
|
|
<a name="l00273"></a>00273 <span class="keywordflow">if</span> (--spw-><a class="code" href="struct_semaphore.html#ae42955cd2346167681e0fd6a136369cd" title="The semaphore counter.">s_cnt</a> < 0) {
|
|
<a name="l00274"></a>00274 <a class="code" href="struct_thread.html" title="Structure representing a thread.">Thread</a> *ctp = currp;
|
|
<a name="l00275"></a>00275 sem_insert(ctp, &spw-><a class="code" href="struct_semaphore.html#a26051a38c22dc11a7a2bf37496d8e906" title="Queue of the threads sleeping on this semaphore.">s_queue</a>);
|
|
<a name="l00276"></a>00276 ctp-><a class="code" href="struct_thread.html#a72cd0424b6098ca241fac1f74d21b56a" title="State-specific fields.">p_u</a>.<a class="code" href="struct_thread.html#a4f016b01444741e6f9b420436b748862" title="Pointer to a generic &quot;wait&quot; object.">wtobjp</a> = spw;
|
|
<a name="l00277"></a>00277 <a class="code" href="group__scheduler.html#ga97c1c514b755a1e71caf2f19c1ccf986" title="Puts the current thread to sleep into the specified state.">chSchGoSleepS</a>(<a class="code" href="group__threads.html#gad0b81cae859c0a6bc6a0d2036aa8e272" title="Thread state: Waiting on a semaphore.">THD_STATE_WTSEM</a>);
|
|
<a name="l00278"></a>00278 msg = ctp-><a class="code" href="struct_thread.html#a72cd0424b6098ca241fac1f74d21b56a" title="State-specific fields.">p_u</a>.<a class="code" href="struct_thread.html#ad5792c30fbd60df0de223b0f398fc6d7" title="Thread wakeup code.">rdymsg</a>;
|
|
<a name="l00279"></a>00279 }
|
|
<a name="l00280"></a>00280 <span class="keywordflow">else</span> {
|
|
<a name="l00281"></a>00281 <a class="code" href="group__scheduler.html#ga4e38b4bee3d2330f6a0f1cdb7660af20" title="Performs a reschedule if a higher priority thread is runnable.">chSchRescheduleS</a>();
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<a name="l00282"></a>00282 msg = RDY_OK;
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<a name="l00283"></a>00283 }
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<a name="l00284"></a>00284 <a class="code" href="group__system.html#ga5a257fa58a09815eb64a45e2dfbdc22e" title="Leaves the kernel lock mode.">chSysUnlock</a>();
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<a name="l00285"></a>00285 <span class="keywordflow">return</span> msg;
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<a name="l00286"></a>00286 }
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<a name="l00287"></a>00287 <span class="preprocessor">#endif </span><span class="comment">/* CH_USE_SEMSW */</span>
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<a name="l00288"></a>00288
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<a name="l00289"></a>00289 <span class="preprocessor">#endif </span><span class="comment">/* CH_USE_SEMAPHORES */</span>
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<a name="l00290"></a>00290 <span class="comment"></span>
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<a name="l00291"></a>00291 <span class="comment">/** @} */</span>
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</pre></div></div>
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<hr size="1"><address style="text-align: right;"><small>
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Generated on Sun Nov 28 2010 14:09:48 for ChibiOS/RT by <a href="http://www.doxygen.org/index.html"><img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.7.1</small></address>
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