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glibc  2.9
pthread_spin_lock.c
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00001 /* Copyright (C) 2005 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <atomic.h>
00020 #include "pthreadP.h"
00021 
00022 int
00023 pthread_spin_lock (pthread_spinlock_t *lock)
00024 {
00025 #if 0
00026   volatile unsigned int *addr = __ldcw_align (lock);
00027 
00028   while (__ldcw (addr) == 0)
00029     while (*addr == 0) ;
00030 
00031   return 0;
00032 #endif
00033 
00034   while (atomic_compare_and_exchange_val_acq(lock, 1, 0) == 1)
00035     while (*lock == 1);
00036   
00037   return 0;
00038 }