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/*
 * ====================================================
 * Copyright (C) 1998, 2002, 2008 by Red Hat Inc. All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

        #include "i386mach.h"

        .global SYM (strlen)
       SOTYPE_FUNCTION(strlen)

SYM (strlen):

        pushl ebp
        movl esp,ebp
        pushl edi
        movl 8(ebp),edx

#ifdef __OPTIMIZE_SIZE__
        cld
        movl edx,edi
        movl $4294967295,ecx
        xor eax,eax
        repnz
        scasb
#else
/* Modern x86 hardware is much faster at double-word
   manipulation than with bytewise repnz scasb.  */

/* Do byte-wise checks until string is aligned.  */
        movl edx,edi
        test $3,edi
        je L5
        movb (edi),cl
        incl edi
        testb cl,cl
        je L15

        test $3,edi
        je L5
        movb (edi),cl
        incl edi
        testb cl,cl
        je L15

        test $3,edi
        je L5
        movb (edi),cl
        incl edi
        testb cl,cl
        je L15

L5:
        subl $4,edi

/* loop performing 4 byte mask checking for desired 0 byte */
        .p2align 4,,7
L10:
        addl $4,edi
        movl (edi),ecx
        leal -16843009(ecx),eax
        notl ecx
        andl ecx,eax
        testl $-2139062144,eax
        je L10

/* Find which of four bytes is 0.  */
        notl ecx
        incl edi

        testb cl,cl
        je L15
        incl edi
        shrl $8,ecx

        testb cl,cl
        je L15
        incl edi
        shrl $8,ecx

        testb cl,cl
        je L15
        incl edi

#endif

L15:
        subl edx,edi
        leal -1(edi),eax

        leal -4(ebp),esp
        popl edi
        leave
        ret