MdePkg/Library/BaseLib/Ia32/DisableCache.c

   1 /** @file
   2   AsmDisableCache function
   3
   4   Copyright (c) 2006 - 2008, 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   Set CD bit and clear NW bit of CR0 followed by a WBINVD.
  17
  18   Disables the caches by setting the CD bit of CR0 to 1, clearing the NW bit of CR0 to 0,
  19   and executing a WBINVD instruction.  This function is only available on IA-32 and x64.
  20
  21 **/
  22 VOID
  23 EFIAPI
  24 AsmDisableCache (
  25   VOID
  26   )
  27 {
  28   _asm {
  29     mov     eax, cr0
  30     bts     eax, 30
  31     btr     eax, 29
  32     mov     cr0, eax
  33     wbinvd
  34   }
  35 }
  36