| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This string-include defines all string functions as inline |
| 3 | * functions. Use gcc. It also assumes ds=es=data space, this should be |
| 4 | * normal. Most of the string-functions are rather heavily hand-optimized, |
| 5 | * see especially strtok,strstr,str[c]spn. They should work, but are not |
| 6 | * very easy to understand. Everything is done entirely within the register |
| 7 | * set, making the functions fast and clean. String instructions have been |
| 8 | * used through-out, making for "slightly" unclear code :-) |
| 9 | * |
| 10 | * NO Copyright (C) 1991, 1992 Linus Torvalds, |
| 11 | * consider these trivial functions to be PD. |
| 12 | */ |
| 13 | |
| 14 | /* |
| 15 | * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org> |
| 16 | * |
| 17 | * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. |
| 18 | */ |
| 19 | |
| 20 | /* |
| 21 | * Modified for uClibc by Erik Andersen <andersen@codepoet.org> |
| 22 | * These make no attempt to use nifty things like mmx/3dnow/etc. |
| 23 | * These are not inline, and will therefore not be as fast as |
| 24 | * modifying the headers to use inlines (and cannot therefore |
| 25 | * do tricky things when dealing with const memory). But they |
| 26 | * should (I hope!) be faster than their generic equivalents.... |
| 27 | * |
| 28 | * More importantly, these should provide a good example for |
| 29 | * others to follow when adding arch specific optimizations. |
| 30 | * -Erik |
| 31 | */ |
| 32 | |
| 33 | #include <string.h> |
| 34 | |
| 35 | #undef strlen |
| 36 | size_t strlen(const char *s) |
| 37 | { |
| 38 | int eax, ecx, edi; |
| 39 | __asm__ __volatile__( |
| 40 | " repne; scasb\n" |
| 41 | " notl %%ecx\n" |
| 42 | " leal -1(%%ecx), %%eax\n" |
| 43 | : "=&c" (ecx), "=&D" (edi), "=&a" (eax) |
| 44 | : "0" (0xffffffff), "1" (s), "2" (0) |
| 45 | ); |
| 46 | return eax; |
| 47 | } |
| 48 | libc_hidden_def(strlen) |