1/* memset implement with rep stosb
2 Copyright (C) 2022-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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 <https://www.gnu.org/licenses/>. */
18
19
20#include <sysdep.h>
21
22#if defined USE_MULTIARCH && IS_IN (libc)
23 .text
24ENTRY (__memset_chk_erms)
25 cmp %RDX_LP, %RCX_LP
26 jb HIDDEN_JUMPTARGET (__chk_fail)
27END (__memset_chk_erms)
28
29/* Only used to measure performance of REP STOSB. */
30ENTRY (__memset_erms)
31 /* Skip zero length. */
32 test %RDX_LP, %RDX_LP
33 jz L(stosb_return_zero)
34 mov %RDX_LP, %RCX_LP
35 movzbl %sil, %eax
36 mov %RDI_LP, %RDX_LP
37 rep stosb
38 mov %RDX_LP, %RAX_LP
39 ret
40L(stosb_return_zero):
41 movq %rdi, %rax
42 ret
43END (__memset_erms)
44#endif
45