glibc/sysdeps/hppa/nptl/pthread_spin_lock.c

/* Copyright (C) 2005 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <atomic.h>
#include "pthreadP.h"

int
pthread_spin_lock (pthread_spinlock_t *lock)
{
#if 0
  volatile unsigned int *addr = __ldcw_align (lock);

  while (__ldcw (addr) == 0)
    while (*addr == 0) ;

  return 0;
#endif

  while (atomic_compare_and_exchange_val_acq(lock, 1, 0) == 1)
    while (*lock == 1);
  
  return 0;
}