1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
/* Copyright (C) 2002-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <errno.h>
#include <shlib-compat.h>
ENTRY(__pthread_spin_trylock)
xorl %ecx, %ecx
/* xchg has implicit LOCK prefix. */
xchgl %ecx, (%rdi)
/* Branch on result. Expectation is the use of trylock will be
branching on success/failure so this branch can be used to
to predict the coming branch. It has the benefit of
breaking the likely expensive memory dependency on (%rdi). */
cmpl $1, %ecx
jnz 1f
xorl %eax, %eax
ret
1:
movl $EBUSY, %eax
ret
END(__pthread_spin_trylock)
versioned_symbol (libc, __pthread_spin_trylock, pthread_spin_trylock,
GLIBC_2_34)
#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_2, GLIBC_2_34)
compat_symbol (libpthread, __pthread_spin_trylock, pthread_spin_trylock,
GLIBC_2_2)
#endif
|
