1 | /* |
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2 | * Thread Queue Handler |
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3 | * |
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4 | * |
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5 | * COPYRIGHT (c) 1989-2008. |
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6 | * On-Line Applications Research Corporation (OAR). |
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7 | * |
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8 | * The license and distribution terms for this file may be |
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9 | * found in the file LICENSE in this distribution or at |
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10 | * http://www.rtems.com/license/LICENSE. |
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11 | * |
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12 | * $Id$ |
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13 | */ |
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14 | |
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15 | #if HAVE_CONFIG_H |
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16 | #include "config.h" |
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17 | #endif |
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18 | |
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19 | #include <rtems/system.h> |
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20 | #include <rtems/score/chain.h> |
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21 | #include <rtems/score/isr.h> |
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22 | #include <rtems/score/object.h> |
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23 | #include <rtems/score/states.h> |
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24 | #include <rtems/score/thread.h> |
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25 | #include <rtems/score/threadq.h> |
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26 | #include <rtems/score/tqdata.h> |
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27 | |
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28 | /*PAGE |
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29 | * |
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30 | * _Thread_queue_Dequeue |
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31 | * |
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32 | * This routine removes a thread from the specified threadq. If the |
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33 | * threadq discipline is FIFO, it unblocks a thread, and cancels its |
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34 | * timeout timer. Priority discipline is processed elsewhere. |
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35 | * |
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36 | * Input parameters: |
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37 | * the_thread_queue - pointer to threadq |
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38 | * |
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39 | * Output parameters: |
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40 | * returns - thread dequeued or NULL |
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41 | * |
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42 | * INTERRUPT LATENCY: |
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43 | * check sync |
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44 | */ |
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45 | |
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46 | Thread_Control *_Thread_queue_Dequeue( |
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47 | Thread_queue_Control *the_thread_queue |
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48 | ) |
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49 | { |
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50 | Thread_Control *(*dequeue_p)( Thread_queue_Control * ); |
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51 | Thread_Control *the_thread; |
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52 | ISR_Level level; |
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53 | Thread_blocking_operation_States sync_state; |
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54 | |
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55 | if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_PRIORITY ) |
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56 | dequeue_p = _Thread_queue_Dequeue_priority; |
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57 | else /* must be THREAD_QUEUE_DISCIPLINE_FIFO */ |
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58 | dequeue_p = _Thread_queue_Dequeue_fifo; |
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59 | |
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60 | the_thread = (*dequeue_p)( the_thread_queue ); |
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61 | _ISR_Disable( level ); |
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62 | if ( !the_thread ) { |
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63 | sync_state = the_thread_queue->sync_state; |
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64 | if ( (sync_state == THREAD_BLOCKING_OPERATION_TIMEOUT) || |
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65 | (sync_state == THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED) ) { |
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66 | the_thread_queue->sync_state = THREAD_BLOCKING_OPERATION_SATISFIED; |
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67 | the_thread = _Thread_Executing; |
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68 | } |
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69 | } |
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70 | _ISR_Enable( level ); |
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71 | return the_thread; |
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72 | } |
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