MdePkg/Library/BaseLib/X64/WriteMsr64.asm

   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 ;   WriteMsr64.Asm
  15 ;
  16 ; Abstract:
  17 ;
  18 ;   AsmWriteMsr64 function
  19 ;
  20 ; Notes:
  21 ;
  22 ;------------------------------------------------------------------------------
  23
  24     .code
  25
  26 ;------------------------------------------------------------------------------
  27 ; UINT64
  28 ; EFIAPI
  29 ; AsmWriteMsr64 (
  30 ;   IN UINT32  Index,
  31 ;   IN UINT64  Value
  32 ;   );
  33 ;------------------------------------------------------------------------------
  34 AsmWriteMsr64   PROC
  35     mov     rax, rdx                    ; meanwhile, rax <- return value
  36     shr     rdx, 20h                    ; edx:eax contains the value to write
  37     wrmsr
  38     ret
  39 AsmWriteMsr64   ENDP
  40
  41     END