CloverBootloader/MdePkg/Library/BaseLib/Ia32/ReadDr4.c
2019-09-03 12:58:42 +03:00

35 lines
575 B
C

/** @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
}
}