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;------------------------------------------------------------------------------
;
; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
; This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution. The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php.
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Module Name:
;
; ReadDr4.Asm
;
; Abstract:
;
; AsmReadDr4 function
;
; Notes:
;
;------------------------------------------------------------------------------
.586p
.model flat,C
.code
;------------------------------------------------------------------------------
; UINTN
; EFIAPI
; AsmReadDr4 (
; VOID
; );
;------------------------------------------------------------------------------
AsmReadDr4 PROC
;
; 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. Here opcode is used.
;
DB 0fh, 21h, 0e0h
ret
AsmReadDr4 ENDP
END
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