osfmk/i386/bcopy.s

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58
  59 #include <i386/asm.h>
  60
  61 /* void *memcpy((void *) to, (const void *) from, (size_t) bcount) */
  62
  63 ENTRY(memcpy)
  64         pushl   %edi
  65         pushl   %esi
  66         movl    8+ 4(%esp),%edi         /* to */
  67         movl    %edi,%eax               /* returns its first argument */
  68         movl    8+ 8(%esp),%esi         /* from */
  69 memcpy_common:
  70         movl    8+ 12(%esp),%edx        /* number of bytes */
  71         cld
  72 /* move longs*/
  73         movl    %edx,%ecx
  74         shrl    $2,%ecx
  75         rep
  76         movsl
  77 /* move bytes*/
  78         movl    %edx,%ecx
  79         andl    $3,%ecx
  80         rep
  81         movsb
  82         popl    %esi
  83         popl    %edi
  84         ret
  85
  86 /* void bcopy((const char *) from, (char *) to, (unsigned int) count) */
  87
  88 ENTRY(bcopy_no_overwrite)
  89         pushl   %edi
  90         pushl   %esi
  91         movl    8+ 8(%esp),%edi         /* to */
  92         movl    8+ 4(%esp),%esi         /* from */
  93         jmp     memcpy_common
  94
  95 /* bcopy16(from, to, bcount) using word moves */
  96
  97 ENTRY(bcopy16)
  98         pushl   %edi
  99         pushl   %esi
 100         movl    8+12(%esp),%edx         /*  8 for the two pushes above */
 101         movl    8+ 8(%esp),%edi
 102         movl    8+ 4(%esp),%esi
 103 /* move words */
 104 0:      cld
 105         movl    %edx,%ecx
 106         shrl    $1,%ecx
 107         rep
 108         movsw
 109 /* move bytes */
 110         movl    %edx,%ecx
 111         andl    $1,%ecx
 112         rep
 113         movsb
 114         popl    %esi
 115         popl    %edi
 116         ret
 117
 118
 119  /*
 120   * Based on NetBSD's bcopy.S from their libc.
 121   * bcopy(src, dst, cnt)
 122   *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
 123   */
 124 ENTRY(bcopy)
 125                 pushl   %esi
 126                 pushl   %edi
 127                 movl    12(%esp),%esi
 128                 movl    16(%esp),%edi
 129                 movl    20(%esp),%ecx
 130
 131                 movl    %edi,%edx
 132                 subl    %esi,%edx
 133                 cmpl    %ecx,%edx                       /* overlapping && src < dst? */
 134                         movl    %ecx,%edx
 135                 jb      1f
 136
 137                 shrl    $2,%ecx                         /* copy by 32-bit words */
 138                 cld                                     /* nope, copy forwards */
 139                 rep
 140                 movsl
 141                 movl    %edx,%ecx
 142                 andl    $3,%ecx                         /* any bytes left? */
 143                 rep
 144                 movsb
 145                 popl    %edi
 146                 popl    %esi
 147                 ret
 148
 149
 150 1:
 151                 addl    %ecx,%edi                       /* copy backwards */
 152                 addl    %ecx,%esi
 153                 decl    %edi
 154                 decl    %esi
 155                 andl    $3,%ecx                         /* any fractional bytes? */
 156                 std
 157                 rep
 158                 movsb
 159                 movl    %edx,%ecx                   /* copy remainder by 32-bit words */
 160                 shrl    $2,%ecx
 161                 subl    $3,%esi
 162                 subl    $3,%edi
 163                 rep
 164                 movsl
 165                 popl    %edi
 166                 popl    %esi
 167                 cld
 168                 ret