MdePkg/Library/BaseLib/Ia32/EnableCache.nasm

;------------------------------------------------------------------------------
;
; Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
; This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution.  The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php.
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Module Name:
;
;   EnableCache.Asm
;
; Abstract:
;
;  Flush all caches with a WBINVD instruction, clear the CD bit of CR0 to 0, and clear
;  the NW bit of CR0 to 0
;
; Notes:
;
;------------------------------------------------------------------------------

    SECTION .text

;------------------------------------------------------------------------------
; VOID
; EFIAPI
; AsmEnableCache (
;   VOID
;   );
;------------------------------------------------------------------------------
global ASM_PFX(AsmEnableCache)
ASM_PFX(AsmEnableCache):
    wbinvd
    mov     eax, cr0
    btr     eax, 29
    btr     eax, 30
    mov     cr0, eax
    ret