]>
Commit | Line | Data |
---|---|---|
3eb9473e | 1 | /*++\r |
2 | \r | |
2c7e5c2f HT |
3 | Copyright (c) 2004 - 2006, Intel Corporation. All rights reserved.<BR>\r |
4 | This program and the accompanying materials \r | |
3eb9473e | 5 | are licensed and made available under the terms and conditions of the BSD License \r |
6 | which accompanies this distribution. The full text of the license may be found at \r | |
7 | http://opensource.org/licenses/bsd-license.php \r | |
8 | \r | |
9 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r | |
10 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. \r | |
11 | \r | |
12 | \r | |
13 | Module Name:\r | |
14 | \r | |
15 | HighBitSet64.c\r | |
16 | \r | |
17 | Abstract: \r | |
18 | \r | |
19 | Math worker functions.\r | |
20 | \r | |
21 | --*/\r | |
22 | \r | |
c7f33ca4 | 23 | #include "BaseLibInternals.h"\r |
3eb9473e | 24 | \r |
25 | /**\r | |
26 | Returns the bit position of the highest bit set in a 64-bit value. Equivalent\r | |
27 | to log2(x).\r | |
28 | \r | |
29 | This function computes the bit position of the highest bit set in the 64-bit\r | |
30 | value specified by Operand. If Operand is zero, then -1 is returned.\r | |
31 | Otherwise, a value between 0 and 63 is returned.\r | |
32 | \r | |
33 | @param Operand The 64-bit operand to evaluate.\r | |
34 | \r | |
35 | @return Position of the highest bit set in Operand if found.\r | |
36 | @retval -1 Operand is zero.\r | |
37 | \r | |
38 | **/\r | |
39 | INTN\r | |
40 | EFIAPI\r | |
41 | HighBitSet64 (\r | |
42 | IN UINT64 Operand\r | |
43 | )\r | |
44 | {\r | |
45 | if (Operand == (UINT32)Operand) {\r | |
46 | //\r | |
47 | // Operand is just a 32-bit integer\r | |
48 | //\r | |
49 | return HighBitSet32 ((UINT32)Operand);\r | |
50 | }\r | |
51 | \r | |
52 | //\r | |
53 | // Operand is really a 64-bit integer\r | |
54 | //\r | |
55 | if (sizeof (UINTN) == sizeof (UINT32)) {\r | |
56 | return HighBitSet32 (((UINT32*)&Operand)[1]) + 32;\r | |
57 | } else {\r | |
58 | return HighBitSet32 ((UINT32)RShiftU64 (Operand, 32)) + 32;\r | |
59 | }\r | |
60 | }\r |