MdePkg/Library/BaseLib/Ia32/ReadPmc.c

   1 /** @file
   2   AsmReadPmc function
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 /**
  10   Reads the current value of a Performance Counter (PMC).
  11
  12   Reads and returns the current value of performance counter specified by
  13   Index. This function is only available on IA-32 and x64.
  14
  15   @param  Index The 32-bit Performance Counter index to read.
  16
  17   @return The value of the PMC specified by Index.
  18
  19 **/
  20 UINT64
  21 EFIAPI
  22 AsmReadPmc (
  23   IN UINT32  Index
  24   )
  25 {
  26   _asm {
  27     mov     ecx, Index
  28     rdpmc
  29   }
  30 }