/* * 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