MdePkg/Library/BaseLib/Ia32/EnableCache.c

   1 /** @file
   2   AsmEnableCache 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   Perform a WBINVD and clear both the CD and NW bits of CR0.
  17
  18   Enables the caches by executing a WBINVD instruction and then clear both the CD and NW
  19   bits of CR0 to 0.  This function is only available on IA-32 and x64.
  20
  21 **/
  22 VOID
  23 EFIAPI
  24 AsmEnableCache (
  25   VOID
  26   )
  27 {
  28   _asm {
  29     wbinvd
  30     mov     eax, cr0
  31     btr     eax, 30
  32     btr     eax, 29
  33     mov     cr0, eax
  34   }
  35 }
  36