MdePkg/Library/BaseLib/Ia32/ReadCr4.c


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/** @file
  AsmReadCr4 function

  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/


/**
  Reads the current value of the Control Register 4 (CR4).

  Reads and returns the current value of CR4. This function is only available
  on IA-32 and x64. This returns a 32-bit value on IA-32 and a 64-bit value on
  x64.

  @return The value of the Control Register 4 (CR4).

**/
UINTN
EFIAPI
AsmReadCr4 (
  VOID
  )
{
  __asm {
    _emit  0x0f  // mov  eax, cr4
    _emit  0x20
    _emit  0xE0
  }
}