arch/x86/boot/copy.S

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright (C) 1991, 1992 Linus Torvalds
   4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
   5  *
   6  *   This file is part of the Linux kernel, and is made available under
   7  *   the terms of the GNU General Public License version 2.
   8  *
   9  * ----------------------------------------------------------------------- */
  10
  11 #include <linux/linkage.h>
  12
  13 /*
  14  * Memory copy routines
  15  */
  16
  17         .code16
  18         .text
  19
  20 GLOBAL(memcpy)
  21         pushw   %si
  22         pushw   %di
  23         movw    %ax, %di
  24         movw    %dx, %si
  25         pushw   %cx
  26         shrw    $2, %cx
  27         rep; movsl
  28         popw    %cx
  29         andw    $3, %cx
  30         rep; movsb
  31         popw    %di
  32         popw    %si
  33         retl
  34 ENDPROC(memcpy)
  35
  36 GLOBAL(memset)
  37         pushw   %di
  38         movw    %ax, %di
  39         movzbl  %dl, %eax
  40         imull   $0x01010101,%eax
  41         pushw   %cx
  42         shrw    $2, %cx
  43         rep; stosl
  44         popw    %cx
  45         andw    $3, %cx
  46         rep; stosb
  47         popw    %di
  48         retl
  49 ENDPROC(memset)
  50
  51 GLOBAL(copy_from_fs)
  52         pushw   %ds
  53         pushw   %fs
  54         popw    %ds
  55         calll   memcpy
  56         popw    %ds
  57         retl
  58 ENDPROC(copy_from_fs)
  59
  60 GLOBAL(copy_to_fs)
  61         pushw   %es
  62         pushw   %fs
  63         popw    %es
  64         calll   memcpy
  65         popw    %es
  66         retl
  67 ENDPROC(copy_to_fs)
  68
  69 #if 0 /* Not currently used, but can be enabled as needed */
  70 GLOBAL(copy_from_gs)
  71         pushw   %ds
  72         pushw   %gs
  73         popw    %ds
  74         calll   memcpy
  75         popw    %ds
  76         retl
  77 ENDPROC(copy_from_gs)
  78
  79 GLOBAL(copy_to_gs)
  80         pushw   %es
  81         pushw   %gs
  82         popw    %es
  83         calll   memcpy
  84         popw    %es
  85         retl
  86 ENDPROC(copy_to_gs)
  87 #endif