MdePkg/Library/BaseLib/Ia32/EnableCache.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2008, Intel Corporation
   4 # All rights reserved. This program and the accompanying materials
   5 # are licensed and made available under the terms and conditions of the BSD License
   6 # which accompanies this distribution.  The full text of the license may be found at
   7 # http://opensource.org/licenses/bsd-license.php
   8 #
   9 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #
  12 # Module Name:
  13 #
  14 #   EnableCache.S
  15 #
  16 # Abstract:
  17 #
  18 #   Flush all caches with a WBINVD instruction, clear the CD bit of CR0 to 0, and clear
  19 #   the NW bit of CR0 to 0
  20 #
  21 # Notes:
  22 #
  23 #------------------------------------------------------------------------------
  24
  25 #------------------------------------------------------------------------------
  26 # VOID
  27 # EFIAPI
  28 # AsmEnableCache (
  29 #   VOID
  30 #   );
  31 #------------------------------------------------------------------------------
  32 ASM_GLOBAL ASM_PFX(AsmEnableCache)
  33 ASM_PFX(AsmEnableCache):
  34     wbinvd
  35     movl    %cr0, %eax
  36     btrl    $30, %eax
  37     btrl    $29, %eax
  38     movl    %eax, %cr0
  39     ret