1/*
2 * pthread_spin_lock.c
3 *
4 * Description:
5 * This translation unit implements spin lock primitives.
6 *
7 * --------------------------------------------------------------------------
8 *
9 *      Pthreads-win32 - POSIX Threads Library for Win32
10 *      Copyright(C) 1998 John E. Bossom
11 *      Copyright(C) 1999,2005 Pthreads-win32 contributors
12 *
13 *      Contact Email: rpj@callisto.canberra.edu.au
14 *
15 *      The current list of contributors is contained
16 *      in the file CONTRIBUTORS included with the source
17 *      code distribution. The list can also be seen at the
18 *      following World Wide Web location:
19 *      http://sources.redhat.com/pthreads-win32/contributors.html
20 *
21 *      This library is free software; you can redistribute it and/or
22 *      modify it under the terms of the GNU Lesser General Public
23 *      License as published by the Free Software Foundation; either
24 *      version 2 of the License, or (at your option) any later version.
25 *
26 *      This library is distributed in the hope that it will be useful,
27 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
28 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
29 *      Lesser General Public License for more details.
30 *
31 *      You should have received a copy of the GNU Lesser General Public
32 *      License along with this library in the file COPYING.LIB;
33 *      if not, write to the Free Software Foundation, Inc.,
34 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
35 */
36
37#include "pthread.h"
38#include "implement.h"
39
40
41int
42pthread_spin_lock (pthread_spinlock_t * lock)
43{
44  register pthread_spinlock_t s;
45
46  if (NULL == lock || NULL == *lock)
47    {
48      return (EINVAL);
49    }
50
51  if (*lock == PTHREAD_SPINLOCK_INITIALIZER)
52    {
53      int result;
54
55      if ((result = ptw32_spinlock_check_need_init (lock)) != 0)
56	{
57	  return (result);
58	}
59    }
60
61  s = *lock;
62
63  while ((PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED ==
64	 PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR) &s->interlock,
65					          (PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED,
66					          (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED))
67    {
68    }
69
70  if (s->interlock == PTW32_SPIN_LOCKED)
71    {
72      return 0;
73    }
74  else if (s->interlock == PTW32_SPIN_USE_MUTEX)
75    {
76      return pthread_mutex_lock (&(s->u.mutex));
77    }
78
79  return EINVAL;
80}
81