MdePkg/Library/BaseLib/Ia32/DisablePaging32.c

   1 /** @file
   2   AsmDisablePaging32 function.
   3
   4   Copyright (c) 2006, Intel Corporation<BR>
   5   All rights reserved. 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 #if _MSC_EXTENSIONS
  16
  17 __declspec (naked)
  18 VOID
  19 EFIAPI
  20 InternalX86DisablePaging32 (
  21   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  22   IN      VOID                      *Context1,    OPTIONAL
  23   IN      VOID                      *Context2,    OPTIONAL
  24   IN      VOID                      *NewStack
  25   )
  26 {
  27   _asm {
  28     push    ebp
  29     mov     ebp, esp
  30     mov     ebx, EntryPoint
  31     mov     ecx, Context1
  32     mov     edx, Context2
  33     pushfd
  34     pop     edi                         // save EFLAGS to edi
  35     cli
  36     mov     eax, cr0
  37     btr     eax, 31
  38     mov     esp, NewStack
  39     mov     cr0, eax
  40     push    edi
  41     popfd                               // restore EFLAGS from edi
  42     push    edx
  43     push    ecx
  44     call    ebx
  45     jmp     $                           // EntryPoint() should not return
  46   }
  47 }
  48
  49 #endif