MdePkg/Library/BaseLib/Ia32/ReadTsc.c

   1 /** @file
   2   AsmReadTsc function
   3
   4   Copyright (c) 2006 - 2007, 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
  17
  18 /**
  19   Reads the current value of Time Stamp Counter (TSC).
  20
  21   Reads and returns the current value of TSC. This function is only available
  22   on IA-32 and X64.
  23
  24   @return The current value of TSC
  25
  26 **/
  27 UINT64
  28 EFIAPI
  29 AsmReadTsc (
  30   VOID
  31   )
  32 {
  33   _asm {
  34     rdtsc
  35   }
  36 }
  37