1/* Highly optimized version for ix86, x>=6.
2 Copyright (C) 1999-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <sysdep.h>
20#include "asm-syntax.h"
21
22#define PARMS 4 /* no space for saved regs */
23#define STR1 PARMS
24#define STR2 STR1+4
25
26 .text
27ENTRY (strcmp)
28
29 movl STR1(%esp), %ecx
30 movl STR2(%esp), %edx
31
32L(oop): movb (%ecx), %al
33 cmpb (%edx), %al
34 jne L(neq)
35 incl %ecx
36 incl %edx
37 testb %al, %al
38 jnz L(oop)
39
40 xorl %eax, %eax
41 /* when strings are equal, pointers rest one beyond
42 the end of the NUL terminators. */
43 ret
44
45L(neq): movl $1, %eax
46 movl $-1, %ecx
47 cmovbl %ecx, %eax
48
49 ret
50END (strcmp)
51libc_hidden_builtin_def (strcmp)
52

source code of glibc/sysdeps/i386/i686/strcmp.S