MdePkg/BaseLib: Support IA32 processors without CLFLUSH

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / DisableCache.c

/** @file\r
  AsmDisableCache function\r
\r
  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php.\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
/**\r
  Set CD bit and clear NW bit of CR0 followed by a WBINVD.\r
\r
  Disables the caches by setting the CD bit of CR0 to 1, clearing the NW bit of CR0 to 0,\r
  and executing a WBINVD instruction.  This function is only available on IA-32 and x64.\r
\r
**/\r
VOID\r
EFIAPI\r
AsmDisableCache (\r
  VOID\r
  )\r
{\r
  _asm {\r
    mov     eax, cr0\r
    bts     eax, 30\r
    btr     eax, 29\r
    mov     cr0, eax\r
    wbinvd\r
  }\r
}\r
\r