1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Inlined Routines Associated with the SuperCore Semaphore |
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5 | * |
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6 | * This include file contains all of the inlined routines associated |
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7 | * with the SuperCore semaphore. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * COPYRIGHT (c) 1989-2006. |
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12 | * On-Line Applications Research Corporation (OAR). |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * http://www.rtems.org/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #ifndef _RTEMS_SCORE_CORESEMIMPL_H |
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20 | #define _RTEMS_SCORE_CORESEMIMPL_H |
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21 | |
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22 | #include <rtems/score/coresem.h> |
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23 | #include <rtems/score/objectimpl.h> |
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24 | #include <rtems/score/threaddispatch.h> |
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25 | #include <rtems/score/threadimpl.h> |
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26 | #include <rtems/score/threadqimpl.h> |
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27 | #include <rtems/score/statesimpl.h> |
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28 | #include <rtems/score/status.h> |
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29 | |
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30 | #ifdef __cplusplus |
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31 | extern "C" { |
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32 | #endif |
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33 | |
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34 | /** |
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35 | * @addtogroup ScoreSemaphore |
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36 | */ |
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37 | /**@{**/ |
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38 | |
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39 | /** |
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40 | * @brief Initialize the semaphore based on the parameters passed. |
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41 | * |
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42 | * This package is the implementation of the CORE Semaphore Handler. |
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43 | * This core object utilizes standard Dijkstra counting semaphores to provide |
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44 | * synchronization and mutual exclusion capabilities. |
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45 | * |
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46 | * This routine initializes the semaphore based on the parameters passed. |
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47 | * |
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48 | * @param[in] the_semaphore is the semaphore to initialize |
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49 | * @param[in] initial_value is the initial count of the semaphore |
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50 | */ |
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51 | void _CORE_semaphore_Initialize( |
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52 | CORE_semaphore_Control *the_semaphore, |
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53 | uint32_t initial_value |
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54 | ); |
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55 | |
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56 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Acquire_critical( |
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57 | CORE_semaphore_Control *the_semaphore, |
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58 | Thread_queue_Context *queue_context |
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59 | ) |
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60 | { |
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61 | _Thread_queue_Acquire_critical( &the_semaphore->Wait_queue, queue_context ); |
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62 | } |
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63 | |
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64 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Release( |
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65 | CORE_semaphore_Control *the_semaphore, |
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66 | Thread_queue_Context *queue_context |
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67 | ) |
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68 | { |
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69 | _Thread_queue_Release( &the_semaphore->Wait_queue, queue_context ); |
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70 | } |
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71 | |
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72 | RTEMS_INLINE_ROUTINE void _CORE_semaphore_Destroy( |
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73 | CORE_semaphore_Control *the_semaphore, |
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74 | const Thread_queue_Operations *operations, |
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75 | Thread_queue_Context *queue_context |
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76 | ) |
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77 | { |
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78 | _Thread_queue_Flush_critical( |
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79 | &the_semaphore->Wait_queue.Queue, |
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80 | operations, |
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81 | _Thread_queue_Flush_status_object_was_deleted, |
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82 | queue_context |
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83 | ); |
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84 | _Thread_queue_Destroy( &the_semaphore->Wait_queue ); |
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85 | } |
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86 | |
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87 | /** |
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88 | * @brief Surrender a unit to a semaphore. |
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89 | * |
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90 | * This routine frees a unit to the semaphore. If a task was blocked waiting |
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91 | * for a unit from this semaphore, then that task will be readied and the unit |
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92 | * given to that task. Otherwise, the unit will be returned to the semaphore. |
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93 | * |
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94 | * @param[in] the_semaphore is the semaphore to surrender |
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95 | * @param[in] operations The thread queue operations. |
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96 | * @param[in] queue_context is a temporary variable used to contain the ISR |
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97 | * disable level cookie |
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98 | * |
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99 | * @retval an indication of whether the routine succeeded or failed |
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100 | */ |
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101 | RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Surrender( |
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102 | CORE_semaphore_Control *the_semaphore, |
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103 | const Thread_queue_Operations *operations, |
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104 | uint32_t maximum_count, |
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105 | Thread_queue_Context *queue_context |
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106 | ) |
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107 | { |
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108 | Thread_Control *the_thread; |
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109 | Status_Control status; |
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110 | |
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111 | status = STATUS_SUCCESSFUL; |
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112 | |
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113 | _CORE_semaphore_Acquire_critical( the_semaphore, queue_context ); |
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114 | |
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115 | the_thread = _Thread_queue_First_locked( |
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116 | &the_semaphore->Wait_queue, |
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117 | operations |
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118 | ); |
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119 | if ( the_thread != NULL ) { |
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120 | _Thread_queue_Extract_critical( |
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121 | &the_semaphore->Wait_queue.Queue, |
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122 | operations, |
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123 | the_thread, |
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124 | queue_context |
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125 | ); |
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126 | } else { |
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127 | if ( the_semaphore->count < maximum_count ) |
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128 | the_semaphore->count += 1; |
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129 | else |
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130 | status = STATUS_MAXIMUM_COUNT_EXCEEDED; |
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131 | |
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132 | _CORE_semaphore_Release( the_semaphore, queue_context ); |
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133 | } |
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134 | |
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135 | return status; |
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136 | } |
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137 | |
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138 | /** |
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139 | * This routine returns the current count associated with the semaphore. |
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140 | * |
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141 | * @param[in] the_semaphore is the semaphore to obtain the count of |
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142 | * |
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143 | * @return the current count of this semaphore |
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144 | */ |
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145 | RTEMS_INLINE_ROUTINE uint32_t _CORE_semaphore_Get_count( |
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146 | const CORE_semaphore_Control *the_semaphore |
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147 | ) |
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148 | { |
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149 | return the_semaphore->count; |
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150 | } |
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151 | |
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152 | /** |
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153 | * This routine attempts to receive a unit from the_semaphore. |
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154 | * If a unit is available or if the wait flag is false, then the routine |
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155 | * returns. Otherwise, the calling task is blocked until a unit becomes |
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156 | * available. |
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157 | * |
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158 | * @param[in] the_semaphore is the semaphore to obtain |
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159 | * @param[in] operations The thread queue operations. |
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160 | * @param[in] executing The currently executing thread. |
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161 | * @param[in] wait is true if the thread is willing to wait |
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162 | * @param[in] queue_context is a temporary variable used to contain the ISR |
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163 | * disable level cookie |
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164 | */ |
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165 | RTEMS_INLINE_ROUTINE Status_Control _CORE_semaphore_Seize( |
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166 | CORE_semaphore_Control *the_semaphore, |
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167 | const Thread_queue_Operations *operations, |
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168 | Thread_Control *executing, |
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169 | bool wait, |
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170 | Thread_queue_Context *queue_context |
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171 | ) |
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172 | { |
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173 | _Assert( _ISR_Get_level() != 0 ); |
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174 | |
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175 | _CORE_semaphore_Acquire_critical( the_semaphore, queue_context ); |
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176 | if ( the_semaphore->count != 0 ) { |
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177 | the_semaphore->count -= 1; |
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178 | _CORE_semaphore_Release( the_semaphore, queue_context ); |
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179 | return STATUS_SUCCESSFUL; |
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180 | } |
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181 | |
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182 | if ( !wait ) { |
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183 | _CORE_semaphore_Release( the_semaphore, queue_context ); |
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184 | return STATUS_UNSATISFIED; |
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185 | } |
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186 | |
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187 | _Thread_queue_Context_set_thread_state( |
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188 | queue_context, |
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189 | STATES_WAITING_FOR_SEMAPHORE |
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190 | ); |
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191 | _Thread_queue_Enqueue( |
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192 | &the_semaphore->Wait_queue.Queue, |
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193 | operations, |
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194 | executing, |
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195 | queue_context |
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196 | ); |
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197 | return _Thread_Wait_get_status( executing ); |
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198 | } |
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199 | |
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200 | /** @} */ |
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201 | |
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202 | #ifdef __cplusplus |
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203 | } |
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204 | #endif |
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205 | |
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206 | #endif |
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207 | /* end of include file */ |
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