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Diffstat (limited to 'lib/libc/i386/string/strcmp.S')
| -rw-r--r-- | lib/libc/i386/string/strcmp.S | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/lib/libc/i386/string/strcmp.S b/lib/libc/i386/string/strcmp.S new file mode 100644 index 0000000..07a87b6 --- /dev/null +++ b/lib/libc/i386/string/strcmp.S @@ -0,0 +1,119 @@ +/* + * Copyright (c) 1993 Winning Strategies, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by Winning Strategies, Inc. + * 4. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <machine/asm.h> +__FBSDID("$FreeBSD$"); + +/* + * strcmp(s1, s2) + * return an integer greater than, equal to, or less than 0, + * according as string s1 is greater than, equal to, or less + * than the string s2. + * + * %eax - pointer to s1 + * %edx - pointer to s2 + * + * Written by: + * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. + */ + +/* + * I've unrolled the loop eight times: large enough to make a + * significant difference, and small enough not to totally trash the + * cache. + */ + +ENTRY(strcmp) + movl 0x04(%esp),%eax + movl 0x08(%esp),%edx + jmp L2 /* Jump into the loop! */ + + .align 2,0x90 +L1: incl %eax + incl %edx +L2: movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + jne L3 + incl %eax + incl %edx + movb (%eax),%cl + testb %cl,%cl + je L3 + cmpb %cl,(%edx) + je L1 + .align 2, 0x90 +L3: movzbl (%eax),%eax /* unsigned comparison */ + movzbl (%edx),%edx + subl %edx,%eax + ret |
