EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseLib/GetPowerOfTwo64.c

   1 /*++
   2
   3 Copyright (c) 2004 - 2006, Intel Corporation
   4 All rights reserved. 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
  13 Module Name:
  14
  15   GetPowerOfTwo64.c
  16
  17 Abstract:
  18
  19   Math worker functions.
  20
  21 --*/
  22
  23 #include "BaseLibInternal.h"
  24
  25 /**
  26   Returns the value of the highest bit set in a 64-bit value. Equivalent to
  27   1 << HighBitSet64(x).
  28
  29   This function computes the value of the highest bit set in the 64-bit value
  30   specified by Operand. If Operand is zero, then zero is returned.
  31
  32   @param  Operand The 64-bit operand to evaluate.
  33
  34   @return 1 << HighBitSet64(Operand)
  35   @retval 0 Operand is zero.
  36
  37 **/
  38 UINT64
  39 EFIAPI
  40 GetPowerOfTwo64 (
  41   IN      UINT64                    Operand
  42   )
  43 {
  44   if (Operand == 0) {
  45     return 0;
  46   }
  47
  48   return LShiftU64 (1, HighBitSet64 (Operand));
  49 }