MdePkg/Library/BaseLib/X64/WriteMsr64.c

   1 /** @file
   2   CpuBreakpoint function.
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 /**
  16   Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  17 **/
  18
  19 void __writemsr (unsigned long Register, unsigned __int64 Value);
  20
  21 #pragma intrinsic(__writemsr)
  22
  23 /**
  24   Write data to MSR.
  25
  26   @param  Index                Register index of MSR.
  27   @param  Value                Data wants to be written.
  28
  29   @return Value written to MSR.
  30
  31 **/
  32 UINT64
  33 EFIAPI
  34 AsmWriteMsr64 (
  35   IN UINT32  Index,
  36   IN UINT64  Value
  37   )
  38 {
  39   __writemsr (Index, Value);
  40   return Value;
  41 }
  42