source: rtems/c/src/exec/rtems/src/semobtain.c @ 9d27732

4.104.114.84.95
Last change on this file since 9d27732 was 9d27732, checked in by Joel Sherrill <joel.sherrill@…>, on 07/06/00 at 19:40:58

Switched to using isr disable version of _Objects_Get. When the
semaphore/mutex can be obtained immediately, this cuts execution time
by 50%.

  • Property mode set to 100644
File size: 3.1 KB
Line 
1/*
2 *  Semaphore Manager
3 *
4 *  DESCRIPTION:
5 *
6 *  This package is the implementation of the Semaphore Manager.
7 *  This manager utilizes standard Dijkstra counting semaphores to provide
8 *  synchronization and mutual exclusion capabilities.
9 *
10 *  Directives provided are:
11 *
12 *     + create a semaphore
13 *     + get an ID of a semaphore
14 *     + delete a semaphore
15 *     + acquire a semaphore
16 *     + release a semaphore
17 *
18 *  COPYRIGHT (c) 1989-1999.
19 *  On-Line Applications Research Corporation (OAR).
20 *
21 *  The license and distribution terms for this file may be
22 *  found in the file LICENSE in this distribution or at
23 *  http://www.OARcorp.com/rtems/license.html.
24 *
25 *  $Id$
26 */
27
28#include <rtems/system.h>
29#include <rtems/rtems/status.h>
30#include <rtems/rtems/support.h>
31#include <rtems/rtems/attr.h>
32#include <rtems/score/isr.h>
33#include <rtems/score/object.h>
34#include <rtems/rtems/options.h>
35#include <rtems/rtems/sem.h>
36#include <rtems/score/coremutex.h>
37#include <rtems/score/coresem.h>
38#include <rtems/score/states.h>
39#include <rtems/score/thread.h>
40#include <rtems/score/threadq.h>
41#if defined(RTEMS_MULTIPROCESSING)
42#include <rtems/score/mpci.h>
43#endif
44#include <rtems/score/sysstate.h>
45
46#include <rtems/score/interr.h>
47
48/*PAGE
49 *
50 *  rtems_semaphore_obtain
51 *
52 *  This directive allows a thread to acquire a semaphore.
53 *
54 *  Input parameters:
55 *    id         - semaphore id
56 *    option_set - wait option
57 *    timeout    - number of ticks to wait (0 means wait forever)
58 *
59 *  Output parameters:
60 *    RTEMS_SUCCESSFUL - if successful
61 *    error code        - if unsuccessful
62 */
63
64rtems_status_code rtems_semaphore_obtain(
65  Objects_Id      id,
66  unsigned32      option_set,
67  rtems_interval  timeout
68)
69{
70  register Semaphore_Control *the_semaphore;
71  Objects_Locations           location;
72  boolean                     wait;
73  ISR_Level                   level;
74
75  the_semaphore = _Semaphore_Get_interrupt_disable( id, &location, &level );
76  switch ( location ) {
77    case OBJECTS_REMOTE:
78#if defined(RTEMS_MULTIPROCESSING)
79      return _Semaphore_MP_Send_request_packet(
80          SEMAPHORE_MP_OBTAIN_REQUEST,
81          id,
82          option_set,
83          timeout
84      );
85#endif
86
87    case OBJECTS_ERROR:
88      return RTEMS_INVALID_ID;
89
90    case OBJECTS_LOCAL:
91      if ( _Options_Is_no_wait( option_set ) )
92        wait = FALSE;
93      else
94        wait = TRUE;
95
96      if ( !_Attributes_Is_counting_semaphore(the_semaphore->attribute_set) ) {
97        _CORE_mutex_Seize(
98          &the_semaphore->Core_control.mutex,
99          id,
100          wait,
101          timeout,
102          level
103        );
104        return _Semaphore_Translate_core_mutex_return_code(
105                  _Thread_Executing->Wait.return_code );
106      }
107
108      /* must be a counting semaphore */
109      _CORE_semaphore_Seize_isr_disable(
110        &the_semaphore->Core_control.semaphore,
111        id,
112        wait,
113        timeout,
114        &level
115      );
116      return _Semaphore_Translate_core_semaphore_return_code(
117                  _Thread_Executing->Wait.return_code );
118  }
119
120  return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */
121}
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