MdePkg/Library/BaseLib/X64/ReadMsr64.nasm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
   4 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   5 ;
   6 ; Module Name:
   7 ;
   8 ;   ReadMsr64.Asm
   9 ;
  10 ; Abstract:
  11 ;
  12 ;   AsmReadMsr64 function
  13 ;
  14 ; Notes:
  15 ;
  16 ;------------------------------------------------------------------------------
  17
  18     DEFAULT REL
  19     SECTION .text
  20
  21 ;------------------------------------------------------------------------------
  22 ; UINT64
  23 ; EFIAPI
  24 ; AsmReadMsr64 (
  25 ;   IN UINT32  Index
  26 ;   );
  27 ;------------------------------------------------------------------------------
  28 global ASM_PFX(AsmReadMsr64)
  29 ASM_PFX(AsmReadMsr64):
  30     rdmsr                               ; edx & eax are zero extended
  31     shl     rdx, 0x20
  32     or      rax, rdx
  33     ret
  34