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e1f414b6 1/** @file\r
2 Math worker functions.\r
3\r
373ade0e 4 Copyright (c) 2006 - 2008, Intel Corporation<BR>\r
e1f414b6 5 All rights reserved. This program and the accompanying materials\r
6 are licensed and made available under the terms and conditions of the BSD License\r
7 which accompanies this distribution. The full text of the license may be found at\r
8 http://opensource.org/licenses/bsd-license.php\r
9\r
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
12\r
13**/\r
14\r
1efcc4ae 15\r
f734a10a 16\r
e1f414b6 17\r
18#include "BaseLibInternals.h"\r
19\r
20/**\r
21 Returns the bit position of the lowest bit set in a 64-bit value.\r
22\r
23 This function computes the bit position of the lowest bit set in the 64-bit\r
24 value specified by Operand. If Operand is zero, then -1 is returned.\r
25 Otherwise, a value between 0 and 63 is returned.\r
26\r
27 @param Operand The 64-bit operand to evaluate.\r
28\r
9aa049d9 29 @retval 0..63 The lowest bit set in Operand was found.\r
30 @retval -1 Operand is zero.\r
31\r
e1f414b6 32\r
33**/\r
34INTN\r
35EFIAPI\r
36LowBitSet64 (\r
37 IN UINT64 Operand\r
38 )\r
39{\r
40 INTN BitIndex;\r
41\r
42 if (Operand == 0) {\r
43 return -1;\r
44 }\r
45\r
46 for (BitIndex = 0;\r
47 (Operand & 1) == 0;\r
48 BitIndex++, Operand = RShiftU64 (Operand, 1));\r
49 return BitIndex;\r
50}\r