MdePkg/Library/BaseLib/X64/WriteMsr64.nasm

   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     DEFAULT REL
  25     SECTION .text
  26
  27 ;------------------------------------------------------------------------------
  28 ; UINT64
  29 ; EFIAPI
  30 ; AsmWriteMsr64 (
  31 ;   IN UINT32  Index,
  32 ;   IN UINT64  Value
  33 ;   );
  34 ;------------------------------------------------------------------------------
  35 global ASM_PFX(AsmWriteMsr64)
  36 ASM_PFX(AsmWriteMsr64):
  37     mov     rax, rdx                    ; meanwhile, rax <- return value
  38     shr     rdx, 0x20                    ; edx:eax contains the value to write
  39     wrmsr
  40     ret
  41