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/*
* This string-include defines all string functions as inline
* functions. Use gcc. It also assumes ds=es=data space, this should be
* normal. Most of the string-functions are rather heavily hand-optimized,
* see especially strtok,strstr,str[c]spn. They should work, but are not
* very easy to understand. Everything is done entirely within the register
* set, making the functions fast and clean. String instructions have been
* used through-out, making for "slightly" unclear code :-)
*
* NO Copyright (C) 1991, 1992 Linus Torvalds,
* consider these trivial functions to be PD.
*/
/*
* Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org>
*
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
/*
* Modified for uClibc by Erik Andersen <andersen@codepoet.org>
* These make no attempt to use nifty things like mmx/3dnow/etc.
* These are not inline, and will therefore not be as fast as
* modifying the headers to use inlines (and cannot therefore
* do tricky things when dealing with const memory). But they
* should (I hope!) be faster than their generic equivalents....
*
* More importantly, these should provide a good example for
* others to follow when adding arch specific optimizations.
* -Erik
*/
#include <string.h>
#undef memmove
//#define memmove TESTING
void *memmove(void *dest, const void *src, size_t n)
{
int eax, ecx, esi, edi;
__asm__ __volatile__(
" movl %%eax, %%edi\n"
" cmpl %%esi, %%eax\n"
" je 2f\n" /* (optional) src == dest -> NOP */
" jb 1f\n" /* src > dest -> simple copy */
" leal -1(%%esi,%%ecx), %%esi\n"
" leal -1(%%eax,%%ecx), %%edi\n"
" std\n"
"1: rep; movsb\n"
" cld\n"
"2:\n"
: "=&c" (ecx), "=&S" (esi), "=&a" (eax), "=&D" (edi)
: "0" (n), "1" (src), "2" (dest)
: "memory"
);
return (void*)eax;
}
#ifndef memmove
libc_hidden_def(memmove)
#else
/* Uncomment TESTING, gcc -D__USE_GNU -m32 -Os memmove.c -o memmove
* and run ./memmove
*/
int main()
{
static char str[] = "abcdef.123";
memmove(str + 1, str, 5);
printf(strcmp(str, "aabcde.123") == 0 ? "ok\n" : "BAD!\n");
memmove(str, str + 1, 5);
printf(strcmp(str, "abcdee.123") == 0 ? "ok\n" : "BAD!\n");
}
#endif
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