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| 1 | /* |
1 | /* |
| 2 | * Copyright (c) 2006 Ondrej Palkovsky |
2 | * Copyright (c) 2006 Ondrej Palkovsky |
| 3 | * All rights reserved. |
3 | * All rights reserved. |
| 4 | * |
4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
7 | * are met: |
| 8 | * |
8 | * |
| 9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
| 14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
| 15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
| 16 | * |
16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | */ |
27 | */ |
| 28 | 28 | ||
| 29 | /** @addtogroup generic |
29 | /** @addtogroup generic |
| 30 | * @{ |
30 | * @{ |
| 31 | */ |
31 | */ |
| 32 | /** @file |
32 | /** @file |
| 33 | */ |
33 | */ |
| 34 | 34 | ||
| 35 | #ifndef KERN_BITOPS_H_ |
35 | #ifndef KERN_BITOPS_H_ |
| 36 | #define KERN_BITOPS_H_ |
36 | #define KERN_BITOPS_H_ |
| 37 | 37 | ||
| 38 | #include <typedefs.h> |
- | |
| 39 | - | ||
| 40 | 38 | ||
| 41 | /** Return position of first non-zero bit from left (i.e. [log_2(arg)]). |
39 | /** Return position of first non-zero bit from left (i.e. [log_2(arg)]). |
| 42 | * |
40 | * |
| 43 | * If number is zero, it returns 0 |
41 | * If number is zero, it returns 0 |
| 44 | */ |
42 | */ |
| 45 | static inline int fnzb32(uint32_t arg) |
43 | static inline int fnzb32(uint32_t arg) |
| 46 | { |
44 | { |
| 47 | int n = 0; |
45 | int n = 0; |
| 48 | 46 | ||
| 49 | if (arg >> 16) { |
47 | if (arg >> 16) { |
| 50 | arg >>= 16; |
48 | arg >>= 16; |
| 51 | n += 16; |
49 | n += 16; |
| 52 | } |
50 | } |
| 53 | 51 | ||
| 54 | if (arg >> 8) { |
52 | if (arg >> 8) { |
| 55 | arg >>= 8; |
53 | arg >>= 8; |
| 56 | n += 8; |
54 | n += 8; |
| 57 | } |
55 | } |
| 58 | 56 | ||
| 59 | if (arg >> 4) { |
57 | if (arg >> 4) { |
| 60 | arg >>= 4; |
58 | arg >>= 4; |
| 61 | n += 4; |
59 | n += 4; |
| 62 | } |
60 | } |
| 63 | 61 | ||
| 64 | if (arg >> 2) { |
62 | if (arg >> 2) { |
| 65 | arg >>= 2; |
63 | arg >>= 2; |
| 66 | n += 2; |
64 | n += 2; |
| 67 | } |
65 | } |
| 68 | 66 | ||
| 69 | if (arg >> 1) { |
67 | if (arg >> 1) { |
| 70 | arg >>= 1; |
68 | arg >>= 1; |
| 71 | n += 1; |
69 | n += 1; |
| 72 | } |
70 | } |
| 73 | 71 | ||
| 74 | return n; |
72 | return n; |
| 75 | } |
73 | } |
| 76 | 74 | ||
| 77 | static inline int fnzb64(uint64_t arg) |
75 | static inline int fnzb64(uint64_t arg) |
| 78 | { |
76 | { |
| 79 | int n = 0; |
77 | int n = 0; |
| 80 | 78 | ||
| 81 | if (arg >> 32) { |
79 | if (arg >> 32) { |
| 82 | arg >>= 32; |
80 | arg >>= 32; |
| 83 | n += 32; |
81 | n += 32; |
| 84 | } |
82 | } |
| 85 | 83 | ||
| 86 | return n + fnzb32((uint32_t) arg); |
84 | return n + fnzb32((uint32_t) arg); |
| 87 | } |
85 | } |
| 88 | 86 | ||
| 89 | #define fnzb(x) fnzb32(x) |
87 | #define fnzb(x) fnzb32(x) |
| 90 | 88 | ||
| 91 | #endif |
89 | #endif |
| 92 | 90 | ||
| 93 | /** @} |
91 | /** @} |
| 94 | */ |
92 | */ |
| 95 | 93 | ||