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      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 ;   ReadDr5.Asm
     15 ;
     16 ; Abstract:
     17 ;
     18 ;   AsmReadDr5 function
     19 ;
     20 ; Notes:
     21 ;
     22 ;------------------------------------------------------------------------------
     23 
     24     SECTION .text
     25 
     26 ;------------------------------------------------------------------------------
     27 ; UINTN
     28 ; EFIAPI
     29 ; AsmReadDr5 (
     30 ;   VOID
     31 ;   );
     32 ;------------------------------------------------------------------------------
     33 global ASM_PFX(AsmReadDr5)
     34 ASM_PFX(AsmReadDr5):
     35     ;
     36     ; DR5 is alias to DR7 only if DE (in CR4) is cleared. Otherwise, reading
     37     ; this register will cause a #UD exception.
     38     ;
     39     ; MS assembler doesn't support this instruction since no one would use it
     40     ; under normal circustances. Here opcode is used.
     41     ;
     42     DB      0xf, 0x21, 0xe8
     43     ret
     44 
     45