diff options
Diffstat (limited to 'sysdeps/x86_64/multiarch/memmove-erms.S')
| -rw-r--r-- | sysdeps/x86_64/multiarch/memmove-erms.S | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/memmove-erms.S b/sysdeps/x86_64/multiarch/memmove-erms.S new file mode 100644 index 0000000000..2d3a6ccb76 --- /dev/null +++ b/sysdeps/x86_64/multiarch/memmove-erms.S @@ -0,0 +1,72 @@ +/* memcpy/mempcpy/memmove implement with rep movsb + Copyright (C) 2022 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 |