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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 memchr
/*#define memchr TESTING*/
void *memchr(const void *s, int c, size_t count)
{
void *edi;
int ecx;
__asm__ __volatile__(
" jecxz 1f\n"
" repne; scasb\n"
" leal -1(%%edi), %%edi\n"
" je 2f\n"
"1:\n"
" xorl %%edi, %%edi\n" /* NULL */
"2:\n"
: "=&D" (edi), "=&c" (ecx)
: "a" (c), "0" (s), "1" (count)
/* : no clobbers */
);
return edi;
}
#ifndef memchr
libc_hidden_def(memchr)
#else
/* Uncomment TESTING, gcc -D_GNU_SOURCE -m32 -Os memchr.c -o memchr
* and run ./memchr
*/
int main()
{
static const char str[] = "abc.def";
printf((char*)memchr(str, '.',-2) - str == 3 ? "ok\n" : "BAD!\n");
printf((char*)memchr(str, '.',-1) - str == 3 ? "ok\n" : "BAD!\n");
printf((char*)memchr(str, '.', 0) == NULL ? "ok\n" : "BAD!\n");
printf((char*)memchr(str, '.', 1) == NULL ? "ok\n" : "BAD!\n");
printf((char*)memchr(str, '.', 2) == NULL ? "ok\n" : "BAD!\n");
printf((char*)memchr(str, '.', 3) == NULL ? "ok\n" : "BAD!\n");
printf((char*)memchr(str, '.', 4) - str == 3 ? "ok\n" : "BAD!\n");
printf((char*)memchr(str, '.', 5) - str == 3 ? "ok\n" : "BAD!\n");
printf((char*)memchr(str+3, '.', 0) == NULL ? "ok\n" : "BAD!\n");
printf((char*)memchr(str+3, '.', 5) - str == 3 ? "ok\n" : "BAD!\n");
}
#endif
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