;------------------------------------------------------------------------------
;
; Copyright (c) 2006, 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. Here opcode is used.
    ;
    DB      0xf, 0x23, 0xe0
    ret