[3a4ae6c] | 1 | /* |
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| 2 | * CORE Semaphore Handler |
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| 3 | * |
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| 4 | * DESCRIPTION: |
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| 5 | * |
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| 6 | * This package is the implementation of the CORE Semaphore Handler. |
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| 7 | * This core object utilizes standard Dijkstra counting semaphores to provide |
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| 8 | * synchronization and mutual exclusion capabilities. |
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| 9 | * |
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[60b791ad] | 10 | * COPYRIGHT (c) 1989-1998. |
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[3a4ae6c] | 11 | * On-Line Applications Research Corporation (OAR). |
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[03f2154e] | 12 | * Copyright assigned to U.S. Government, 1994. |
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[3a4ae6c] | 13 | * |
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[98e4ebf5] | 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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[03f2154e] | 16 | * http://www.OARcorp.com/rtems/license.html. |
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[3a4ae6c] | 17 | * |
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| 18 | * $Id$ |
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| 19 | */ |
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| 20 | |
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| 21 | #include <rtems/system.h> |
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[5e9b32b] | 22 | #include <rtems/score/isr.h> |
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| 23 | #include <rtems/score/coresem.h> |
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| 24 | #include <rtems/score/states.h> |
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| 25 | #include <rtems/score/thread.h> |
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| 26 | #include <rtems/score/threadq.h> |
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[97e2729d] | 27 | #if defined(RTEMS_MULTIPROCESSING) |
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[5e9b32b] | 28 | #include <rtems/score/mpci.h> |
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[97e2729d] | 29 | #endif |
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[3a4ae6c] | 30 | |
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| 31 | /*PAGE |
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| 32 | * |
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| 33 | * CORE_semaphore_Initialize |
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| 34 | * |
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| 35 | * This function initialize a semaphore and sets the initial value based |
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| 36 | * on the given count. |
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| 37 | * |
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| 38 | * Input parameters: |
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| 39 | * the_semaphore - the semaphore control block to initialize |
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| 40 | * the_class - the API class of the object |
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| 41 | * the_semaphore_attributes - the attributes specified at create time |
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| 42 | * initial_value - semaphore's initial value |
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| 43 | * proxy_extract_callout - MP specific extract callout |
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| 44 | * |
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| 45 | * Output parameters: NONE |
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| 46 | */ |
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| 47 | |
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| 48 | void _CORE_semaphore_Initialize( |
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| 49 | CORE_semaphore_Control *the_semaphore, |
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| 50 | Objects_Classes the_class, |
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| 51 | CORE_semaphore_Attributes *the_semaphore_attributes, |
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| 52 | unsigned32 initial_value, |
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| 53 | Thread_queue_Extract_callout proxy_extract_callout |
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| 54 | ) |
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| 55 | { |
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| 56 | |
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| 57 | the_semaphore->Attributes = *the_semaphore_attributes; |
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| 58 | the_semaphore->count = initial_value; |
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| 59 | |
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| 60 | _Thread_queue_Initialize( |
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| 61 | &the_semaphore->Wait_queue, |
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| 62 | the_class, |
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| 63 | _CORE_semaphore_Is_priority( the_semaphore_attributes ) ? |
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| 64 | THREAD_QUEUE_DISCIPLINE_PRIORITY : THREAD_QUEUE_DISCIPLINE_FIFO, |
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| 65 | STATES_WAITING_FOR_SEMAPHORE, |
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| 66 | proxy_extract_callout, |
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| 67 | CORE_SEMAPHORE_TIMEOUT |
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| 68 | ); |
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| 69 | } |
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| 70 | |
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| 71 | /*PAGE |
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| 72 | * |
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| 73 | * _CORE_semaphore_Surrender |
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| 74 | * |
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| 75 | * Input parameters: |
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| 76 | * the_semaphore - the semaphore to be flushed |
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| 77 | * id - id of parent semaphore |
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| 78 | * api_semaphore_mp_support - api dependent MP support actions |
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| 79 | * |
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| 80 | * Output parameters: |
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| 81 | * CORE_SEMAPHORE_STATUS_SUCCESSFUL - if successful |
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| 82 | * core error code - if unsuccessful |
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| 83 | * |
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| 84 | * Output parameters: |
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| 85 | */ |
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| 86 | |
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| 87 | CORE_semaphore_Status _CORE_semaphore_Surrender( |
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| 88 | CORE_semaphore_Control *the_semaphore, |
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| 89 | Objects_Id id, |
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| 90 | CORE_semaphore_API_mp_support_callout api_semaphore_mp_support |
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| 91 | ) |
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| 92 | { |
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| 93 | Thread_Control *the_thread; |
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[8f0529f] | 94 | ISR_Level level; |
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| 95 | CORE_semaphore_Status status; |
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| 96 | |
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| 97 | status = CORE_SEMAPHORE_STATUS_SUCCESSFUL; |
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[3a4ae6c] | 98 | |
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| 99 | if ( (the_thread = _Thread_queue_Dequeue(&the_semaphore->Wait_queue)) ) { |
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| 100 | |
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| 101 | if ( !_Objects_Is_local_id( the_thread->Object.id ) ) |
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| 102 | (*api_semaphore_mp_support) ( the_thread, id ); |
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| 103 | |
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[8f0529f] | 104 | } else { |
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| 105 | _ISR_Disable( level ); |
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| 106 | if ( the_semaphore->count <= the_semaphore->Attributes.maximum_count ) |
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| 107 | the_semaphore->count += 1; |
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| 108 | else |
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| 109 | status = CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED; |
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| 110 | _ISR_Enable( level ); |
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| 111 | } |
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[3a4ae6c] | 112 | |
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[8f0529f] | 113 | return status; |
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[3a4ae6c] | 114 | } |
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| 115 | |
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| 116 | /*PAGE |
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| 117 | * |
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| 118 | * _CORE_semaphore_Seize |
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| 119 | * |
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| 120 | * This routine attempts to allocate a core semaphore to the calling thread. |
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| 121 | * |
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| 122 | * Input parameters: |
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| 123 | * the_semaphore - pointer to semaphore control block |
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| 124 | * id - id of object to wait on |
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| 125 | * wait - TRUE if wait is allowed, FALSE otherwise |
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| 126 | * timeout - number of ticks to wait (0 means forever) |
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| 127 | * |
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| 128 | * Output parameters: NONE |
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| 129 | * |
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| 130 | * INTERRUPT LATENCY: |
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| 131 | * available |
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| 132 | * wait |
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| 133 | */ |
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| 134 | |
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| 135 | void _CORE_semaphore_Seize( |
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| 136 | CORE_semaphore_Control *the_semaphore, |
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| 137 | Objects_Id id, |
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| 138 | boolean wait, |
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| 139 | Watchdog_Interval timeout |
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| 140 | ) |
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| 141 | { |
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| 142 | Thread_Control *executing; |
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| 143 | ISR_Level level; |
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| 144 | |
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| 145 | executing = _Thread_Executing; |
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| 146 | executing->Wait.return_code = CORE_SEMAPHORE_STATUS_SUCCESSFUL; |
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| 147 | _ISR_Disable( level ); |
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| 148 | if ( the_semaphore->count != 0 ) { |
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| 149 | the_semaphore->count -= 1; |
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| 150 | _ISR_Enable( level ); |
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| 151 | return; |
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| 152 | } |
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| 153 | |
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| 154 | if ( !wait ) { |
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| 155 | _ISR_Enable( level ); |
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| 156 | executing->Wait.return_code = CORE_SEMAPHORE_STATUS_UNSATISFIED_NOWAIT; |
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| 157 | return; |
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| 158 | } |
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| 159 | |
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[67d224a] | 160 | _Thread_queue_Enter_critical_section( &the_semaphore->Wait_queue ); |
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[3a4ae6c] | 161 | executing->Wait.queue = &the_semaphore->Wait_queue; |
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| 162 | executing->Wait.id = id; |
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| 163 | _ISR_Enable( level ); |
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| 164 | |
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| 165 | _Thread_queue_Enqueue( &the_semaphore->Wait_queue, timeout ); |
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| 166 | } |
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| 167 | |
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| 168 | |
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| 169 | /*PAGE |
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| 170 | * |
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| 171 | * _CORE_semaphore_Flush |
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| 172 | * |
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| 173 | * This function a flushes the semaphore's task wait queue. |
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| 174 | * |
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| 175 | * Input parameters: |
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| 176 | * the_semaphore - the semaphore to be flushed |
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| 177 | * remote_extract_callout - function to invoke remotely |
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| 178 | * status - status to pass to thread |
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| 179 | * |
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| 180 | * Output parameters: NONE |
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| 181 | */ |
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| 182 | |
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| 183 | void _CORE_semaphore_Flush( |
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| 184 | CORE_semaphore_Control *the_semaphore, |
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| 185 | Thread_queue_Flush_callout remote_extract_callout, |
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| 186 | unsigned32 status |
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| 187 | ) |
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| 188 | { |
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| 189 | |
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| 190 | _Thread_queue_Flush( |
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| 191 | &the_semaphore->Wait_queue, |
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| 192 | remote_extract_callout, |
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| 193 | status |
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| 194 | ); |
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| 195 | |
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| 196 | } |
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