1/* Copyright (C) 2002-2020 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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 <https://www.gnu.org/licenses/>. */
18
19#include <pthread-errnos.h>
20#include <sysdep.h>
21
22
23#ifdef UP
24# define LOCK
25#else
26# define LOCK lock
27#endif
28
29ENTRY(pthread_spin_trylock)
30 movl $1, %eax
31 xorl %ecx, %ecx
32 LOCK
33 cmpxchgl %ecx, (%rdi)
34 movl $EBUSY, %eax
35 cmovel %ecx, %eax
36 retq
37END(pthread_spin_trylock)
38