MdePkg/Library/BaseLib/Ia32/ReadGdtr.c

   1 /** @file
   2   AsmReadGdtr function
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   5   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 "BaseLibInternals.h"
  17
  18
  19 /**
  20   Reads the current Global Descriptor Table Register(GDTR) descriptor.
  21
  22   Reads and returns the current GDTR descriptor and returns it in Gdtr. This
  23   function is only available on IA-32 and x64.
  24
  25   @param  Gdtr  The pointer to a GDTR descriptor.
  26
  27 **/
  28 VOID
  29 EFIAPI
  30 InternalX86ReadGdtr (
  31   OUT IA32_DESCRIPTOR  *Gdtr
  32   )
  33 {
  34   _asm {
  35     mov     eax, Gdtr
  36     sgdt    fword ptr [eax]
  37   }
  38 }
  39