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path: root/MdePkg/Library/BaseLib/Ia32/WriteDr5.nasm
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;------------------------------------------------------------------------------
;
; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Module Name:
;
;   WriteDr5.Asm
;
; Abstract:
;
;   AsmWriteDr5 function
;
; Notes:
;
;------------------------------------------------------------------------------

    SECTION .text

;------------------------------------------------------------------------------
; UINTN
; EFIAPI
; AsmWriteDr5 (
;   IN UINTN Value
;   );
;------------------------------------------------------------------------------
global ASM_PFX(AsmWriteDr5)
ASM_PFX(AsmWriteDr5):
    mov     eax, [esp + 4]
    ;
    ; DR5 is alias to DR7 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 circumstances.
    ;
    mov     dr5, eax
    ret