glibc/nptl/sysdeps/i386/pthread_spin_lock.c

50 lines
1.4 KiB
C

/* Copyright (C) 2002, 2003 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include "pthreadP.h"
#ifndef LOCK_PREFIX
# ifdef UP
# define LOCK_PREFIX /* nothing */
# else
# define LOCK_PREFIX "lock;"
# endif
#endif
int
pthread_spin_lock (lock)
pthread_spinlock_t *lock;
{
asm ("\n"
"1:\t" LOCK_PREFIX "decl %0\n\t"
"jne 2f\n\t"
".subsection 1\n\t"
".align 16\n"
"2:\trep; nop\n\t"
"cmpl $0, %0\n\t"
"jg 1b\n\t"
"jmp 2b\n\t"
".previous"
: "=m" (*lock)
: "0" (*lock));
return 0;
}