i386/gen/bcopy.s

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*-
  23  * Copyright (c) 1990 The Regents of the University of California.
  24  * All rights reserved.
  25  *
  26  * This code is derived from locore.s.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  */
  56
  57 #include <architecture/i386/asm_help.h>
  58
  59         /*
  60          * (ov)bcopy (src,dst,cnt)
  61          *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
  62          */
  63
  64 TEXT
  65 #ifdef MEMCOPY
  66 LEAF(_memcpy,0)
  67 #else
  68 #ifdef MEMMOVE
  69 LEAF(_memmove,0)
  70 #else
  71 LEAF(_bcopy,0)
  72 #endif
  73 #endif
  74         pushl   %esi
  75         pushl   %edi
  76 #if defined(MEMCOPY) || defined(MEMMOVE)
  77         movl    12(%esp),%edi
  78         movl    16(%esp),%esi
  79 #else
  80         movl    12(%esp),%esi
  81         movl    16(%esp),%edi
  82 #endif
  83         movl    20(%esp),%ecx
  84         movl    %edi,%eax
  85         subl    %esi,%eax
  86         cmpl    %ecx,%eax       /* overlapping? */
  87         jb      1f
  88         cld                     /* nope, copy forwards. */
  89         shrl    $2,%ecx         /* copy by words */
  90         rep
  91         movsl
  92         movl    20(%esp),%ecx
  93         andl    $3,%ecx         /* any bytes left? */
  94         rep
  95         movsb
  96 #if defined(MEMCOPY) || defined(MEMMOVE)
  97         movl    12(%esp),%eax
  98 #endif
  99         popl    %edi
 100         popl    %esi
 101         ret
 102 1:
 103         addl    %ecx,%edi       /* copy backwards. */
 104         addl    %ecx,%esi
 105         std
 106         andl    $3,%ecx         /* any fractional bytes? */
 107         decl    %edi
 108         decl    %esi
 109         rep
 110         movsb
 111         movl    20(%esp),%ecx   /* copy remainder by words */
 112         shrl    $2,%ecx
 113         subl    $3,%esi
 114         subl    $3,%edi
 115         rep
 116         movsl
 117 #if defined(MEMCOPY) || defined(MEMMOVE)
 118         movl    12(%esp),%eax
 119 #endif
 120         popl    %edi
 121         popl    %esi
 122         cld
 123 END(bcopy)