1/* memcpy/mempcpy/memmove implement with rep movsb
2 Copyright (C) 2022 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 (__mempcpy_chk_erms)
25 cmp %RDX_LP, %RCX_LP
26 jb HIDDEN_JUMPTARGET (__chk_fail)
27END (__mempcpy_chk_erms)
28
29/* Only used to measure performance of REP MOVSB. */
30ENTRY (__mempcpy_erms)
31 mov %RDI_LP, %RAX_LP
32 /* Skip zero length. */
33 test %RDX_LP, %RDX_LP
34 jz 2f
35 add %RDX_LP, %RAX_LP
36 jmp L(start_movsb)
37END (__mempcpy_erms)
38
39ENTRY (__memmove_chk_erms)
40 cmp %RDX_LP, %RCX_LP
41 jb HIDDEN_JUMPTARGET (__chk_fail)
42END (__memmove_chk_erms)
43
44ENTRY (__memmove_erms)
45 movq %rdi, %rax
46 /* Skip zero length. */
47 test %RDX_LP, %RDX_LP
48 jz 2f
49L(start_movsb):
50 mov %RDX_LP, %RCX_LP
51 cmp %RSI_LP, %RDI_LP
52 jb 1f
53 /* Source == destination is less common. */
54 je 2f
55 lea (%rsi,%rcx), %RDX_LP
56 cmp %RDX_LP, %RDI_LP
57 jb L(movsb_backward)
581:
59 rep movsb
602:
61 ret
62L(movsb_backward):
63 leaq -1(%rdi,%rcx), %rdi
64 leaq -1(%rsi,%rcx), %rsi
65 std
66 rep movsb
67 cld
68 ret
69END (__memmove_erms)
70strong_alias (__memmove_erms, __memcpy_erms)
71strong_alias (__memmove_chk_erms, __memcpy_chk_erms)
72#endif
73