glibc/sysdeps/ia64/nptl/pthread_spin_lock.c

35 lines
1.1 KiB
C

/* Copyright (C) 2003-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
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, see
<http://www.gnu.org/licenses/>. */
#include "pthreadP.h"
int
pthread_spin_lock (pthread_spinlock_t *lock)
{
int *p = (int *) lock;
while (__builtin_expect (__sync_val_compare_and_swap (p, 0, 1), 0))
{
/* Spin without using the atomic instruction. */
do
__asm __volatile ("hint @pause" : : : "memory");
while (*p);
}
return 0;
}