MdePkg/Library/BaseLib/Ia32/ReadDs.c

   1 /** @file
   2   AsmReadDs function
   3
   4   Copyright (c) 2006 - 2007, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 //
  16 // Include common header file for this module.
  17 //
  18
  19
  20 /**
  21   Reads the current value of Data Segment Register (DS).
  22
  23   Reads and returns the current value of DS. This function is only available on
  24   IA-32 and X64.
  25
  26   @return The current value of DS.
  27
  28 **/
  29 UINT16
  30 EFIAPI
  31 AsmReadDs (
  32   VOID
  33   )
  34 {
  35   __asm {
  36     xor     eax, eax
  37     mov     ax, ds
  38   }
  39 }
  40