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 /*
  12  * arch/i386/boot/copy.S
  13  *
  14  * Memory copy routines
  15  */
  16
  17         .code16gcc
  18         .text
  19
  20         .globl  memcpy
  21         .type   memcpy, @function
  22 memcpy:
  23         pushw   %si
  24         pushw   %di
  25         movw    %ax, %di
  26         movw    %dx, %si
  27         pushw   %cx
  28         shrw    $2, %cx
  29         rep; movsl
  30         popw    %cx
  31         andw    $3, %cx
  32         rep; movsb
  33         popw    %di
  34         popw    %si
  35         ret
  36         .size   memcpy, .-memcpy
  37
  38         .globl  memset
  39         .type   memset, @function
  40 memset:
  41         pushw   %di
  42         movw    %ax, %di
  43         movzbl  %dl, %eax
  44         imull   $0x01010101,%eax
  45         pushw   %cx
  46         shrw    $2, %cx
  47         rep; stosl
  48         popw    %cx
  49         andw    $3, %cx
  50         rep; stosb
  51         popw    %di
  52         ret
  53         .size   memset, .-memset
  54
  55         .globl  copy_from_fs
  56         .type   copy_from_fs, @function
  57 copy_from_fs:
  58         pushw   %ds
  59         pushw   %fs
  60         popw    %ds
  61         call    memcpy
  62         popw    %ds
  63         ret
  64         .size   copy_from_fs, .-copy_from_fs
  65
  66         .globl  copy_to_fs
  67         .type   copy_to_fs, @function
  68 copy_to_fs:
  69         pushw   %es
  70         pushw   %fs
  71         popw    %es
  72         call    memcpy
  73         popw    %es
  74         ret
  75         .size   copy_to_fs, .-copy_to_fs
  76
  77 #if 0 /* Not currently used, but can be enabled as needed */
  78
  79         .globl  copy_from_gs
  80         .type   copy_from_gs, @function
  81 copy_from_gs:
  82         pushw   %ds
  83         pushw   %gs
  84         popw    %ds
  85         call    memcpy
  86         popw    %ds
  87         ret
  88         .size   copy_from_gs, .-copy_from_gs
  89         .globl  copy_to_gs
  90
  91         .type   copy_to_gs, @function
  92 copy_to_gs:
  93         pushw   %es
  94         pushw   %gs
  95         popw    %es
  96         call    memcpy
  97         popw    %es
  98         ret
  99         .size   copy_to_gs, .-copy_to_gs
 100
 101 #endif