i386/gen/bcopy.s

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*-
  26  * Copyright (c) 1990 The Regents of the University of California.
  27  * All rights reserved.
  28  *
  29  * This code is derived from locore.s.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  * 1. Redistributions of source code must retain the above copyright
  35  *    notice, this list of conditions and the following disclaimer.
  36  * 2. Redistributions in binary form must reproduce the above copyright
  37  *    notice, this list of conditions and the following disclaimer in the
  38  *    documentation and/or other materials provided with the distribution.
  39  * 3. All advertising materials mentioning features or use of this software
  40  *    must display the following acknowledgement:
  41  *      This product includes software developed by the University of
  42  *      California, Berkeley and its contributors.
  43  * 4. Neither the name of the University nor the names of its contributors
  44  *    may be used to endorse or promote products derived from this software
  45  *    without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  */
  59
  60 #include <architecture/i386/asm_help.h>
  61
  62         /*
  63          * (ov)bcopy (src,dst,cnt)
  64          *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
  65          */
  66
  67 TEXT
  68 #ifdef MEMCOPY
  69 LEAF(_memcpy,0)
  70 #else
  71 #ifdef MEMMOVE
  72 LEAF(_memmove,0)
  73 #else
  74 LEAF(_bcopy,0)
  75 #endif
  76 #endif
  77         pushl   %esi
  78         pushl   %edi
  79 #if defined(MEMCOPY) || defined(MEMMOVE)
  80         movl    12(%esp),%edi
  81         movl    16(%esp),%esi
  82 #else
  83         movl    12(%esp),%esi
  84         movl    16(%esp),%edi
  85 #endif
  86         movl    20(%esp),%ecx
  87         movl    %edi,%eax
  88         subl    %esi,%eax
  89         cmpl    %ecx,%eax       /* overlapping? */
  90         jb      1f
  91         cld                     /* nope, copy forwards. */
  92         shrl    $2,%ecx         /* copy by words */
  93         rep
  94         movsl
  95         movl    20(%esp),%ecx
  96         andl    $3,%ecx         /* any bytes left? */
  97         rep
  98         movsb
  99 #if defined(MEMCOPY) || defined(MEMMOVE)
 100         movl    12(%esp),%eax
 101 #endif
 102         popl    %edi
 103         popl    %esi
 104         ret
 105 1:
 106         addl    %ecx,%edi       /* copy backwards. */
 107         addl    %ecx,%esi
 108         std
 109         andl    $3,%ecx         /* any fractional bytes? */
 110         decl    %edi
 111         decl    %esi
 112         rep
 113         movsb
 114         movl    20(%esp),%ecx   /* copy remainder by words */
 115         shrl    $2,%ecx
 116         subl    $3,%esi
 117         subl    $3,%edi
 118         rep
 119         movsl
 120 #if defined(MEMCOPY) || defined(MEMMOVE)
 121         movl    12(%esp),%eax
 122 #endif
 123         popl    %edi
 124         popl    %esi
 125         cld
 126 END(bcopy)