osfmk/i386/bcopy.s

   1 /*
   2  * Copyright (c) 2000 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  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52
  53 #include <i386/asm.h>
  54
  55 /* void *memcpy((void *) to, (const void *) from, (size_t) bcount) */
  56
  57 ENTRY(memcpy)
  58         pushl   %edi
  59         pushl   %esi
  60         movl    8+ 4(%esp),%edi         /* to */
  61         movl    %edi,%eax               /* returns its first argument */
  62         movl    8+ 8(%esp),%esi         /* from */
  63 memcpy_common:
  64         movl    8+ 12(%esp),%edx        /* number of bytes */
  65         cld
  66 /* move longs*/
  67         movl    %edx,%ecx
  68         sarl    $2,%ecx
  69         rep
  70         movsl
  71 /* move bytes*/
  72         movl    %edx,%ecx
  73         andl    $3,%ecx
  74         rep
  75         movsb
  76         popl    %esi
  77         popl    %edi
  78         ret
  79
  80 /* void bcopy((const char *) from, (char *) to, (unsigned int) count) */
  81
  82 ENTRY(bcopy_no_overwrite)
  83         pushl   %edi
  84         pushl   %esi
  85         movl    8+ 8(%esp),%edi         /* to */
  86         movl    8+ 4(%esp),%esi         /* from */
  87         jmp     memcpy_common
  88
  89 /* bcopy16(from, to, bcount) using word moves */
  90
  91 ENTRY(bcopy16)
  92         pushl   %edi
  93         pushl   %esi
  94         movl    8+12(%esp),%edx         /*  8 for the two pushes above */
  95         movl    8+ 8(%esp),%edi
  96         movl    8+ 4(%esp),%esi
  97 /* move words */
  98 0:      cld
  99         movl    %edx,%ecx
 100         sarl    $1,%ecx
 101         rep
 102         movsw
 103 /* move bytes */
 104         movl    %edx,%ecx
 105         andl    $1,%ecx
 106         rep
 107         movsb
 108         popl    %esi
 109         popl    %edi
 110         ret
 111
 112
 113  /*
 114   * Based on NetBSD's bcopy.S from their libc.
 115   * bcopy(src, dst, cnt)
 116   *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
 117   */
 118 ENTRY(bcopy)
 119                 pushl   %esi
 120                 pushl   %edi
 121                 movl    12(%esp),%esi
 122                 movl    16(%esp),%edi
 123                 movl    20(%esp),%ecx
 124
 125                 movl    %edi,%edx
 126                 subl    %esi,%edx
 127                 cmpl    %ecx,%edx                       /* overlapping && src < dst? */
 128                         movl    %ecx,%edx
 129                 jb      1f
 130
 131                 shrl    $2,%ecx                         /* copy by 32-bit words */
 132                 cld                                     /* nope, copy forwards */
 133                 rep
 134                 movsl
 135                 movl    %edx,%ecx
 136                 andl    $3,%ecx                         /* any bytes left? */
 137                 rep
 138                 movsb
 139                 popl    %edi
 140                 popl    %esi
 141                 ret
 142
 143
 144 1:
 145                 addl    %ecx,%edi                       /* copy backwards */
 146                 addl    %ecx,%esi
 147                 decl    %edi
 148                 decl    %esi
 149                 andl    $3,%ecx                         /* any fractional bytes? */
 150                 std
 151                 rep
 152                 movsb
 153                 movl    %edx,%ecx                   /* copy remainder by 32-bit words */
 154                 shrl    $2,%ecx
 155                 subl    $3,%esi
 156                 subl    $3,%edi
 157                 rep
 158                 movsl
 159                 popl    %edi
 160                 popl    %esi
 161                 cld
 162                 ret