/* * 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_GNU_SOURCE -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