1 /* Copyright (C) 2003 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19 #include <errno.h>
20 #include "pthreadP.h"
21
22 int
pthread_spin_trylock(pthread_spinlock_t * lock)23 pthread_spin_trylock (pthread_spinlock_t *lock)
24 {
25 unsigned int old;
26 int err = EBUSY;
27
28 __asm__ ("1: lwarx %0,0,%2\n"
29 " cmpwi 0,%0,0\n"
30 " bne 2f\n"
31 " stwcx. %3,0,%2\n"
32 " bne- 1b\n"
33 " li %1,0\n"
34 " isync\n"
35 "2: "
36 : "=&r" (old), "=&r" (err)
37 : "r" (lock), "r" (1), "1" (err)
38 : "cr0", "memory");
39
40 return err;
41 }
42