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878ddf1f | 1 | /** @file\r |
2 | Math worker functions.\r | |
3 | \r | |
4 | Copyright (c) 2006, Intel Corporation<BR>\r | |
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 | |
15 | #include "BaseLibInternals.h"\r | |
16 | \r | |
17 | /**\r | |
18 | Returns the bit position of the highest bit set in a 64-bit value. Equivalent\r | |
19 | to log2(x).\r | |
20 | \r | |
21 | This function computes the bit position of the highest bit set in the 64-bit\r | |
22 | value specified by Operand. If Operand is zero, then -1 is returned.\r | |
23 | Otherwise, a value between 0 and 63 is returned.\r | |
24 | \r | |
25 | @param Operand The 64-bit operand to evaluate.\r | |
26 | \r | |
27 | @return Position of the highest bit set in Operand if found.\r | |
28 | @retval -1 Operand is zero.\r | |
29 | \r | |
30 | **/\r | |
31 | INTN\r | |
32 | EFIAPI\r | |
33 | HighBitSet64 (\r | |
34 | IN UINT64 Operand\r | |
35 | )\r | |
36 | {\r | |
73c47db8 | 37 | if (Operand == (UINT32)Operand) {\r |
38 | //\r | |
39 | // Operand is just a 32-bit integer\r | |
40 | //\r | |
41 | return HighBitSet32 ((UINT32)Operand);\r | |
42 | }\r | |
43 | \r | |
44 | //\r | |
45 | // Operand is really a 64-bit integer\r | |
46 | //\r | |
47 | if (sizeof (UINTN) == sizeof (UINT32)) {\r | |
48 | return HighBitSet32 (((UINT32*)&Operand)[1]) + 32;\r | |
49 | } else {\r | |
50 | return HighBitSet32 ((UINT32)RShiftU64 (Operand, 32)) + 32;\r | |
51 | }\r | |
878ddf1f | 52 | }\r |