linuxthreads/spinlock.h

   1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
   2 /* threads for Linux.                                                   */
   3 /* Copyright (C) 1998 Xavier Leroy (Xavier.Leroy@inria.fr)              */
   4 /*                                                                      */
   5 /* This program is free software; you can redistribute it and/or        */
   6 /* modify it under the terms of the GNU Library General Public License  */
   7 /* as published by the Free Software Foundation; either version 2       */
   8 /* of the License, or (at your option) any later version.               */
   9 /*                                                                      */
  10 /* This program is distributed in the hope that it will be useful,      */
  11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
  12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
  13 /* GNU Library General Public License for more details.                 */
  14
  15 /* Internal locks */
  16
  17 extern void __pthread_lock(struct _pthread_fastlock * lock);
  18 extern int __pthread_trylock(struct _pthread_fastlock * lock);
  19 extern void __pthread_unlock(struct _pthread_fastlock * lock);
  20
  21 static inline void __pthread_init_lock(struct _pthread_fastlock * lock)
  22 {
  23   lock->status = 0;
  24   lock->spinlock = 0;
  25 }
  26
  27 #define LOCK_INITIALIZER {0, 0}
  28
  29 #if defined(TEST_FOR_COMPARE_AND_SWAP)
  30
  31 extern int __pthread_has_cas;
  32 extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval,
  33                                       int * spinlock);
  34
  35 static inline int compare_and_swap(long * ptr, long oldval, long newval,
  36                                    int * spinlock)
  37 {
  38   if (__pthread_has_cas)
  39     return __compare_and_swap(ptr, oldval, newval);
  40   else
  41     return __pthread_compare_and_swap(ptr, oldval, newval, spinlock);
  42 }
  43
  44 #elif defined(HAS_COMPARE_AND_SWAP)
  45
  46 static inline int compare_and_swap(long * ptr, long oldval, long newval,
  47                                    int * spinlock)
  48 {
  49   return __compare_and_swap(ptr, oldval, newval);
  50 }
  51
  52 #else
  53
  54 extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval,
  55                                       int * spinlock);
  56
  57 static inline int compare_and_swap(long * ptr, long oldval, long newval,
  58                                    int * spinlock)
  59 {
  60   return __pthread_compare_and_swap(ptr, oldval, newval, spinlock);
  61 }
  62
  63 #endif