;------------------------------------------------------------------------------ | |
; | |
; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR> | |
; SPDX-License-Identifier: BSD-2-Clause-Patent | |
; | |
; Module Name: | |
; | |
; ReadDr4.Asm | |
; | |
; Abstract: | |
; | |
; AsmReadDr4 function | |
; | |
; Notes: | |
; | |
;------------------------------------------------------------------------------ | |
SECTION .text | |
;------------------------------------------------------------------------------ | |
; UINTN | |
; EFIAPI | |
; AsmReadDr4 ( | |
; VOID | |
; ); | |
;------------------------------------------------------------------------------ | |
global ASM_PFX(AsmReadDr4) | |
ASM_PFX(AsmReadDr4): | |
; | |
; DR4 is alias to DR6 only if DE (in CR4) is cleared. Otherwise, reading | |
; this register will cause a #UD exception. | |
; | |
; MS assembler doesn't support this instruction since no one would use it | |
; under normal circustances. | |
; | |
mov eax, dr4 | |
ret | |