cosmopolitan/libc/nexgen32e/memmove.S

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/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify │
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License. │
This program 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software │
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/macros.h"
/ Copies memory.
/
/ DEST and SRC may overlap.
/
/ @param rdi is dest
/ @param rsi is src
/ @param rdx is number of bytes
/ @return original rdi copied to rax
/ @asyncsignalsafe
memmove:
mov %rdi,%rax
/ 𝑠𝑙𝑖𝑑𝑒
.endfn MemMove,globl,hidden
MemMove:
.leafprologue
.profilable
push %rcx
push %rdi
push %rsi
mov %rdx,%rcx
cmp %rsi,%rdi
jb 1f
lea -1(%rdi,%rcx),%rdi
lea -1(%rsi,%rcx),%rsi
std
1: rep movsb
cld
pop %rsi
pop %rdi
pop %rcx
.leafepilogue
.endfn memmove,globl
.source __FILE__