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[mirror_edk2.git] / MdePkg / Library / BaseLib / LowBitSet32.c
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e1f414b6 1/** @file\r
2 Math worker functions.\r
3\r
bb817c56 4 Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
9344f092 5 SPDX-License-Identifier: BSD-2-Clause-Patent\r
e1f414b6 6\r
7**/\r
8\r
e1f414b6 9#include "BaseLibInternals.h"\r
10\r
11/**\r
12 Returns the bit position of the lowest bit set in a 32-bit value.\r
13\r
14 This function computes the bit position of the lowest bit set in the 32-bit\r
15 value specified by Operand. If Operand is zero, then -1 is returned.\r
16 Otherwise, a value between 0 and 31 is returned.\r
17\r
18 @param Operand The 32-bit operand to evaluate.\r
19\r
9aa049d9 20 @retval 0..31 The lowest bit set in Operand was found.\r
127010dd 21 @retval -1 Operand is zero.\r
e1f414b6 22\r
23**/\r
24INTN\r
25EFIAPI\r
26LowBitSet32 (\r
2f88bd3a 27 IN UINT32 Operand\r
e1f414b6 28 )\r
29{\r
2f88bd3a 30 INTN BitIndex;\r
e1f414b6 31\r
32 if (Operand == 0) {\r
33 return -1;\r
34 }\r
35\r
2f88bd3a
MK
36 for (BitIndex = 0; 0 == (Operand & 1); BitIndex++, Operand >>= 1) {\r
37 }\r
38\r
e1f414b6 39 return BitIndex;\r
40}\r