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