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/* memcpy/mempcpy/memmove implement with rep movsb
Copyright (C) 2022-2025 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>
#if defined USE_MULTIARCH && IS_IN (libc)
.text
ENTRY (__mempcpy_chk_erms)
cmp %RDX_LP, %RCX_LP
jb HIDDEN_JUMPTARGET (__chk_fail)
END (__mempcpy_chk_erms)
/* Only used to measure performance of REP MOVSB. */
ENTRY (__mempcpy_erms)
mov %RDI_LP, %RAX_LP
/* Skip zero length. */
test %RDX_LP, %RDX_LP
jz 2f
add %RDX_LP, %RAX_LP
jmp L(start_movsb)
END (__mempcpy_erms)
ENTRY (__memmove_chk_erms)
cmp %RDX_LP, %RCX_LP
jb HIDDEN_JUMPTARGET (__chk_fail)
END (__memmove_chk_erms)
ENTRY (__memmove_erms)
movq %rdi, %rax
/* Skip zero length. */
test %RDX_LP, %RDX_LP
jz 2f
L(start_movsb):
mov %RDX_LP, %RCX_LP
cmp %RSI_LP, %RDI_LP
jb 1f
/* Source == destination is less common. */
je 2f
lea (%rsi,%rcx), %RDX_LP
cmp %RDX_LP, %RDI_LP
jb L(movsb_backward)
1:
rep movsb
2:
ret
L(movsb_backward):
leaq -1(%rdi,%rcx), %rdi
leaq -1(%rsi,%rcx), %rsi
std
rep movsb
cld
ret
END (__memmove_erms)
strong_alias (__memmove_erms, __memcpy_erms)
strong_alias (__memmove_chk_erms, __memcpy_chk_erms)
#endif
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