1 /* Copyright (C) 2002,2003,2004 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    <http://www.gnu.org/licenses/>.  */
18 
19 #include "pthreadP.h"
20 
21 #ifndef LOCK_PREFIX
22 # ifdef UP
23 #  define LOCK_PREFIX	/* nothing */
24 # else
25 #  define LOCK_PREFIX	"lock;"
26 # endif
27 #endif
28 
29 
30 int
pthread_spin_lock(pthread_spinlock_t * lock)31 pthread_spin_lock (
32      pthread_spinlock_t *lock)
33 {
34   __asm__ ("\n"
35        "1:\t" LOCK_PREFIX "decl %0\n\t"
36        "jne 2f\n\t"
37        ".subsection 1\n\t"
38        ".align 16\n"
39        "2:\trep; nop\n\t"
40        "cmpl $0, %0\n\t"
41        "jg 1b\n\t"
42        "jmp 2b\n\t"
43        ".previous"
44        : "=m" (*lock)
45        : "m" (*lock));
46 
47   return 0;
48 }
49