| /* |
| * 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 |
| * |
| * 2009-04: modified by Denys Vlasenko <vda.linux@googlemail.com> |
| * Fill byte-by-byte is a bit too slow. I prefer 46 byte function |
| * which fills x4 faster than 21 bytes one. |
| */ |
| |
| #include <string.h> |
| |
| #undef memset |
| void *memset(void *s, int c, size_t count) |
| { |
| int reg, edi; |
| __asm__ __volatile__( |
| |
| /* Most of the time, count is divisible by 4 and nonzero */ |
| /* It's better to make this case faster */ |
| /* " jecxz 9f\n" - (optional) count == 0: goto ret */ |
| " mov %%ecx, %1\n" |
| " shr $2, %%ecx\n" |
| " jz 1f\n" /* zero words: goto fill_bytes */ |
| /* extend 8-bit fill to 32 bits */ |
| " movzx %%al, %%eax\n" /* 3 bytes */ |
| /* or: " and $0xff, %%eax\n" - 5 bytes */ |
| " imul $0x01010101, %%eax\n" /* 6 bytes */ |
| /* fill full words */ |
| " rep; stosl\n" |
| /* fill 0-3 bytes */ |
| "1: and $3, %1\n" |
| " jz 9f\n" /* (count & 3) == 0: goto end */ |
| "2: stosb\n" |
| " dec %1\n" |
| " jnz 2b\n" |
| /* end */ |
| "9:\n" |
| |
| : "=&D" (edi), "=&r" (reg) |
| : "0" (s), "a" (c), "c" (count) |
| : "memory" |
| ); |
| return s; |
| } |
| libc_hidden_def(memset) |
| |
| /* |
| gcc 4.3.1 |
| ========= |
| 57 push %edi |
| 8b 7c 24 08 mov 0x8(%esp),%edi |
| 8b 4c 24 10 mov 0x10(%esp),%ecx |
| 8b 44 24 0c mov 0xc(%esp),%eax |
| 89 ca mov %ecx,%edx |
| c1 e9 02 shr $0x2,%ecx |
| 74 0b je 1f <__GI_memset+0x1f> |
| 0f b6 c0 movzbl %al,%eax |
| 69 c0 01 01 01 01 imul $0x1010101,%eax,%eax |
| f3 ab rep stos %eax,%es:(%edi) |
| 83 e2 03 and $0x3,%edx |
| 74 04 je 28 <__GI_memset+0x28> |
| aa stos %al,%es:(%edi) |
| 4a dec %edx |
| 75 fc jne 24 <__GI_memset+0x24> |
| 8b 44 24 08 mov 0x8(%esp),%eax |
| 5f pop %edi |
| c3 ret |
| */ |