audk/MdePkg/Library/BaseLib/Ia32/WriteDr4.nasm

40 lines
1014 B
NASM

;------------------------------------------------------------------------------
;
; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Module Name:
;
; WriteDr4.Asm
;
; Abstract:
;
; AsmWriteDr4 function
;
; Notes:
;
;------------------------------------------------------------------------------
SECTION .text
;------------------------------------------------------------------------------
; UINTN
; EFIAPI
; AsmWriteDr4 (
; IN UINTN Value
; );
;------------------------------------------------------------------------------
global ASM_PFX(AsmWriteDr4)
ASM_PFX(AsmWriteDr4):
mov eax, [esp + 4]
;
; DR4 is alias to DR6 only if DE (in CR4) is cleared. Otherwise, writing to
; this register will cause a #UD exception.
;
; MS assembler doesn't support this instruction since no one would use it
; under normal circustances.
;
mov dr4, eax
ret