1;------------------------------------------------------------------------------
2;
3; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
4; This program and the accompanying materials
5; are licensed and made available under the terms and conditions of the BSD License
6; which accompanies this distribution.  The full text of the license may be found at
7; http://opensource.org/licenses/bsd-license.php.
8;
9; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
10; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
11;
12; Module Name:
13;
14;   WriteDr4.Asm
15;
16; Abstract:
17;
18;   AsmWriteDr4 function
19;
20; Notes:
21;
22;------------------------------------------------------------------------------
23
24    .586p
25    .model  flat,C
26    .code
27
28;------------------------------------------------------------------------------
29; UINTN
30; EFIAPI
31; AsmWriteDr4 (
32;   IN UINTN Value
33;   );
34;------------------------------------------------------------------------------
35AsmWriteDr4 PROC
36    mov     eax, [esp + 4]
37    ;
38    ; DR4 is alias to DR6 only if DE (in CR4) is cleared. Otherwise, writing to
39    ; this register will cause a #UD exception.
40    ;
41    ; MS assembler doesn't support this instruction since no one would use it
42    ; under normal circustances. Here opcode is used.
43    ;
44    DB      0fh, 23h, 0e0h
45    ret
46AsmWriteDr4 ENDP
47
48    END
49