MdePkg/Library/BaseLib/Ia32/ReadDr5.c

   1 /** @file
   2   AsmReadDr5 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 Debug Register 5 (DR5).
  22
  23   Reads and returns the current value of DR5. This function is only available
  24   on IA-32 and X64. This returns a 32-bit value on IA-32 and a 64-bit value on
  25   X64.
  26
  27   @return The value of Debug Register 5 (DR5).
  28
  29 **/
  30 UINTN
  31 EFIAPI
  32 AsmReadDr5 (
  33   VOID
  34   )
  35 {
  36   __asm {
  37     _emit  0x0f
  38     _emit  0x21
  39     _emit  0xe8
  40   }
  41 }
  42