MdePkg/Library/BaseLib/Ia32/ReadDr4.c


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/** @file
  AsmReadDr4 function

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

**/


/**
  Reads the current value of Debug Register 4 (DR4).

  Reads and returns the current value of DR4. 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 Debug Register 4 (DR4).

**/
UINTN
EFIAPI
AsmReadDr4 (
  VOID
  )
{
  __asm {
    _emit  0x0f
    _emit  0x21
    _emit  0xe0
  }
}