1/* rawmemchr - find a character in a memory zone
2
3 Copyright (C) 2015-2022 Free Software Foundation, Inc.
4
5 This file is part of the GNU C Library.
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library. If not, see
19 <https://www.gnu.org/licenses/>. */
20
21#include <sysdep.h>
22
23/* Special case rawmemchr (s, 0) as strlen, otherwise tailcall memchr.
24 Call strlen without setting up a full frame - it preserves x14/x15.
25*/
26
27ENTRY (__rawmemchr)
28 cbz w1, L(do_strlen)
29 mov x2, -1
30 b __memchr
31
32L(do_strlen):
33 mov x15, x30
34 cfi_return_column (x15)
35 mov x14, x0
36 bl __strlen
37 add x0, x14, x0
38 ret x15
39
40END (__rawmemchr)
41weak_alias (__rawmemchr, rawmemchr)
42libc_hidden_builtin_def (__rawmemchr)
43

source code of glibc/sysdeps/aarch64/rawmemchr.S