1 /** @file
2 Math worker functions.
3
4 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
5 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 #include "BaseLibInternals.h"
19
20 /**
21 Returns the value of the highest bit set in a 64-bit value. Equivalent to
22 1 << log2(x).
23
24 This function computes the value of the highest bit set in the 64-bit value
25 specified by Operand. If Operand is zero, then zero is returned.
26
27 @param Operand The 64-bit operand to evaluate.
28
29 @return 1 << HighBitSet64(Operand)
30 @retval 0 Operand is zero.
31
32 **/
33 UINT64
34 EFIAPI
GetPowerOfTwo64(IN UINT64 Operand)35 GetPowerOfTwo64 (
36 IN UINT64 Operand
37 )
38 {
39 if (Operand == 0) {
40 return 0;
41 }
42
43 return LShiftU64 (1, (UINTN) HighBitSet64 (Operand));
44 }
45