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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 (strchr)
       SOTYPE_FUNCTION(strchr)

SYM (strchr):

        pushl ebp
        movl esp,ebp
        pushl edi
        pushl ebx
        xorl ebx,ebx
        movl 8(ebp),edi
        addb 12(ebp),bl

#ifndef __OPTIMIZE_SIZE__
/* Special case strchr(p,0).  */
        je L25

/* Do byte-wise checks until string is aligned.  */
        test $3,edi
        je L5
        movl edi,eax
        movb (eax),cl
        testb cl,cl
        je L14
        cmpb bl,cl
        je L19
        incl edi

        test $3,edi
        je L5
        movl edi,eax
        movb (eax),cl
        testb cl,cl
        je L14
        cmpb bl,cl
        je L19
        incl edi

        test $3,edi
        je L5
        movl edi,eax
        movb (eax),cl
        testb cl,cl
        je L14
        cmpb bl,cl
        je L19
        incl edi

/* create 4 byte mask which is just the desired byte repeated 4 times */
L5:
        movl ebx,ecx
        sall $8,ebx
        subl $4,edi
        orl ecx,ebx
        movl ebx,edx
        sall $16,ebx
        orl edx,ebx

/* loop performing 4 byte mask checking for 0 byte or desired byte */
        .p2align 4,,7
L10:
        addl $4,edi
        movl (edi),ecx
        leal -16843009(ecx),edx
        movl ecx,eax
        notl eax
        andl eax,edx
        testl $-2139062144,edx
        jne L9

        xorl ebx,ecx
        leal -16843009(ecx),edx
        notl ecx
        andl ecx,edx
        testl $-2139062144,edx
        je L10
#endif /* not __OPTIMIZE_SIZE__ */

/* loop while (*s && *s++ != c) */
L9:
        leal -1(edi),eax
        .p2align 4,,7
L15:
        incl eax
        movb (eax),dl
        testb dl,dl
        je L14
        cmpb bl,dl
        jne L15

L14:
/*  if (*s == c) return address otherwise return NULL */
        cmpb bl,(eax)
        je L19
        xorl eax,eax

L19:
        leal -8(ebp),esp
        popl ebx
        popl edi
        leave
        ret

#ifndef __OPTIMIZE_SIZE__
/* Special case strchr(p,0).  */
#if 0
        /* Hideous performance on modern machines.  */
L25:
        cld
        movl $-1,ecx
        xor eax,eax
        repnz
        scasb
        leal -1(edi),eax
        jmp L19
#endif
L25:
/* Do byte-wise checks until string is aligned.  */
        test $3,edi
        je L26
        movl edi,eax
        movb (eax),cl
        testb cl,cl
        je L19
        incl edi

        test $3,edi
        je L26
        movl edi,eax
        movb (eax),cl
        testb cl,cl
        je L19
        incl edi

        test $3,edi
        je L26
        movl edi,eax
        movb (eax),cl
        testb cl,cl
        je L19
        incl edi

L26:
        subl $4,edi

/* loop performing 4 byte mask checking for desired 0 byte */
        .p2align 4,,7
L27:
        addl $4,edi
        movl (edi),ecx
        leal -16843009(ecx),edx
        movl ecx,eax
        notl eax
        andl eax,edx
        testl $-2139062144,edx
        je L27

        jmp L9

#endif /* !__OPTIMIZE_SIZE__ */