1 /** @file
2 Math worker functions.
3
4 Copyright (c) 2006 - 2008, 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 bit position of the lowest bit set in a 32-bit value.
22
23 This function computes the bit position of the lowest bit set in the 32-bit
24 value specified by Operand. If Operand is zero, then -1 is returned.
25 Otherwise, a value between 0 and 31 is returned.
26
27 @param Operand The 32-bit operand to evaluate.
28
29 @retval 0..31 The lowest bit set in Operand was found.
30 @retval -1 Operand is zero.
31
32 **/
33 INTN
34 EFIAPI
LowBitSet32(IN UINT32 Operand)35 LowBitSet32 (
36 IN UINT32 Operand
37 )
38 {
39 INTN BitIndex;
40
41 if (Operand == 0) {
42 return -1;
43 }
44
45 for (BitIndex = 0; 0 == (Operand & 1); BitIndex++, Operand >>= 1);
46 return BitIndex;
47 }
48