1/* Copyright (C) 2012-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <sysdep.h>
19#include <shlib-compat.h>
20
21ENTRY(__pthread_spin_lock)
22 /* Always return zero. */
23 xor %eax, %eax
24 LOCK
25 decl 0(%rdi)
26 jne 1f
27 ret
28
29 .align 16
301:
31 /* `rep nop` == `pause`. */
32 rep
33 nop
34 cmpl %eax, 0(%rdi)
35 jle 1b
36 /* Just repeat the `lock decl` logic here. The code size save
37 of jumping back to entry doesn't change how many 16-byte
38 chunks (default function alignment) that the code fits in. */
39 LOCK
40 decl 0(%rdi)
41 jne 1b
42 ret
43END(__pthread_spin_lock)
44versioned_symbol (libc, __pthread_spin_lock, pthread_spin_lock, GLIBC_2_34)
45
46#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_2, GLIBC_2_34)
47compat_symbol (libpthread, __pthread_spin_lock, pthread_spin_lock, GLIBC_2_2)
48#endif
49