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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 highest bit set in a 32-bit value. Equivalent\r
13 to log2(x).\r
14\r
15 This function computes the bit position of the highest bit set in the 32-bit\r
16 value specified by Operand. If Operand is zero, then -1 is returned.\r
17 Otherwise, a value between 0 and 31 is returned.\r
18\r
19 @param Operand The 32-bit operand to evaluate.\r
20\r
9aa049d9 21 @retval 0..31 Position of the highest bit set in Operand if found.\r
127010dd 22 @retval -1 Operand is zero.\r
e1f414b6 23\r
24**/\r
25INTN\r
26EFIAPI\r
27HighBitSet32 (\r
2f88bd3a 28 IN UINT32 Operand\r
e1f414b6 29 )\r
30{\r
2f88bd3a 31 INTN BitIndex;\r
e1f414b6 32\r
33 if (Operand == 0) {\r
2f88bd3a 34 return -1;\r
e1f414b6 35 }\r
2f88bd3a
MK
36\r
37 for (BitIndex = 31; (INT32)Operand > 0; BitIndex--, Operand <<= 1) {\r
38 }\r
39\r
e1f414b6 40 return BitIndex;\r
41}\r