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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 64-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 64-bit\r
16 value specified by Operand. If Operand is zero, then -1 is returned.\r
17 Otherwise, a value between 0 and 63 is returned.\r
18\r
19 @param Operand The 64-bit operand to evaluate.\r
20\r
9aa049d9 21 @retval 0..63 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
27HighBitSet64 (\r
2f88bd3a 28 IN UINT64 Operand\r
e1f414b6 29 )\r
30{\r
31 if (Operand == (UINT32)Operand) {\r
32 //\r
33 // Operand is just a 32-bit integer\r
34 //\r
35 return HighBitSet32 ((UINT32)Operand);\r
36 }\r
37\r
38 //\r
39 // Operand is really a 64-bit integer\r
40 //\r
41 if (sizeof (UINTN) == sizeof (UINT32)) {\r
2f88bd3a 42 return HighBitSet32 (((UINT32 *)&Operand)[1]) + 32;\r
e1f414b6 43 } else {\r
44 return HighBitSet32 ((UINT32)RShiftU64 (Operand, 32)) + 32;\r
45 }\r
46}\r