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/*
 * ====================================================
 * Copyright (C) 1998, 2002 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 (memmove)
       SOTYPE_FUNCTION(memmove)

SYM (memmove):

        pushl ebp
        movl esp,ebp
        pushl esi
        pushl edi
        pushl ebx
        movl 8(ebp),edi
        movl 16(ebp),ecx
        movl 12(ebp),esi

/*  check for destructive overlap (src < dst && dst < src + length) */

        cld
        cmpl edi,esi
        jae  .L2
        leal -1(ecx,esi),ebx
        cmpl ebx,edi
        ja   .L2

/* IF:   destructive overlap, must copy backwards */

        addl ecx,esi
        addl ecx,edi
        std

#ifndef __OPTIMIZE_SIZE__
        
        cmpl $8,ecx
        jbe .L13
.L18:

/* move trailing bytes in reverse until destination address is long word aligned */
                
        movl edi,edx
        movl ecx,ebx
        andl $3,edx
        jz .L21
        
        movl edx,ecx
        decl esi
        decl edi
        subl ecx,ebx
        rep
        movsb
        
        mov ebx,ecx
        incl esi
        incl edi

.L21:
        
/* move bytes in reverse, a long word at a time */
                
        shrl $2,ecx
        subl $4,esi
        subl $4,edi
        rep
        movsl
        
        addl $4,esi
        addl $4,edi
        movl ebx,ecx
        andl $3,ecx
        
#endif /* !__OPTIMIZE_SIZE__ */

/* handle any remaining bytes not on a long word boundary */                    
        
.L13: 
        decl esi
        decl edi

.L15:
        rep
        movsb
        jmp .L5
        .p2align 4,,7

/* ELSE:   no destructive overlap so we copy forwards */
                
.L2:

#ifndef __OPTIMIZE_SIZE__
                
        cmpl $8,ecx
        jbe .L3

/* move any preceding bytes until destination address is long word aligned */
                
        movl edi,edx    
        movl ecx,ebx
        andl $3,edx
        jz .L11
        movl $4,ecx
        subl edx,ecx
        andl $3,ecx
        subl ecx,ebx
        rep
        movsb
        
        mov ebx,ecx

/* move bytes a long word at a time */
                
.L11:
        shrl $2,ecx
        .p2align 2
        rep
        movsl
        
        movl ebx,ecx
        andl $3,ecx
        
#endif /* !__OPTIMIZE_SIZE__ */

/* handle any remaining bytes */
                
.L3:            
        rep
        movsb
.L5:            
        movl 8(ebp),eax
        cld

        leal -12(ebp),esp
        popl ebx
        popl edi
        popl esi
        leave
        ret