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glibc  2.9
pspinlock.c
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00001 /* POSIX spinlock implementation.  PowerPC version.
00002    Copyright (C) 2000, 2003 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public License as
00007    published by the Free Software Foundation; either version 2.1 of the
00008    License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; see the file COPYING.LIB.  If not,
00017    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
00018    Boston, MA 02111-1307, USA.  */
00019 
00020 #include <errno.h>
00021 #include <pthread.h>
00022 #include "internals.h"
00023 
00024 int
00025 __pthread_spin_lock (pthread_spinlock_t *lock)
00026 {
00027   while (! __compare_and_swap32 ((int *)lock, 0, 1))
00028     ;
00029   return 0;
00030 }
00031 weak_alias (__pthread_spin_lock, pthread_spin_lock)
00032 
00033 
00034 int
00035 __pthread_spin_trylock (pthread_spinlock_t *lock)
00036 {
00037   return __compare_and_swap32 ((int *)lock, 0, 1) ? 0 : EBUSY;
00038 }
00039 weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
00040 
00041 
00042 int
00043 __pthread_spin_unlock (pthread_spinlock_t *lock)
00044 {
00045   MEMORY_BARRIER ();
00046   *lock = 0;
00047   return 0;
00048 }
00049 weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
00050 
00051 
00052 int
00053 __pthread_spin_init (pthread_spinlock_t *lock, int pshared)
00054 {
00055   /* We can ignore the `pshared' parameter.  Since we are busy-waiting
00056      all processes which can access the memory location `lock' points
00057      to can use the spinlock.  */
00058   *lock = 0;
00059   return 0;
00060 }
00061 weak_alias (__pthread_spin_init, pthread_spin_init)
00062 
00063 
00064 int
00065 __pthread_spin_destroy (pthread_spinlock_t *lock)
00066 {
00067   /* Nothing to do.  */
00068   return 0;
00069 }
00070 weak_alias (__pthread_spin_destroy, pthread_spin_destroy)