glibc/sysdeps/i386/pthread_spin_trylock.S

/* Copyright (C) 2002-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   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 <pthread-errnos.h>


#ifdef UP
# define LOCK
#else
# define LOCK lock
#endif

	.globl	pthread_spin_trylock
	.type	pthread_spin_trylock,@function
	.align	16
pthread_spin_trylock:
	movl	4(%esp), %edx
	movl	$1, %eax
	xorl	%ecx, %ecx
	LOCK
	cmpxchgl %ecx, (%edx)
	movl	$EBUSY, %eax
#ifdef HAVE_CMOV
	cmovel	%ecx, %eax
#else
	jne	0f
	movl	%ecx, %eax
0:
#endif
	ret
	.size	pthread_spin_trylock,.-pthread_spin_trylock