MdePkg/Library/BaseLib/X64/DisableCache.nasm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   4 ; 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 ;   DisableCache.Asm
  15 ;
  16 ; Abstract:
  17 ;
  18 ;   Set the CD bit of CR0 to 1, clear the NW bit of CR0 to 0, and flush all caches with a
  19 ;   WBINVD instruction.
  20 ;
  21 ; Notes:
  22 ;
  23 ;------------------------------------------------------------------------------
  24
  25     DEFAULT REL
  26     SECTION .text
  27
  28 ;------------------------------------------------------------------------------
  29 ; VOID
  30 ; EFIAPI
  31 ; AsmDisableCache (
  32 ;   VOID
  33 ;   );
  34 ;------------------------------------------------------------------------------
  35 global ASM_PFX(AsmDisableCache)
  36 ASM_PFX(AsmDisableCache):
  37     mov     rax, cr0
  38     bts     rax, 30
  39     btr     rax, 29
  40     mov     cr0, rax
  41     wbinvd
  42     ret
  43