1 /*
2 * Copyright 2011-2015 Samy Al Bahra.
3 * Copyright 2011 David Joseph.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 /*
29 * Several of these are from: http://graphics.stanford.edu/~seander/bithacks.html
30 */
31
32 #define CK_INTERNAL_LOG_0 (0xAAAAAAAA)
33 #define CK_INTERNAL_LOG_1 (0xCCCCCCCC)
34 #define CK_INTERNAL_LOG_2 (0xF0F0F0F0)
35 #define CK_INTERNAL_LOG_3 (0xFF00FF00)
36 #define CK_INTERNAL_LOG_4 (0xFFFF0000)
37
38 CK_CC_INLINE static uint32_t
ck_internal_log(uint32_t v)39 ck_internal_log(uint32_t v)
40 {
41 uint32_t r = (v & CK_INTERNAL_LOG_0) != 0;
42
43 r |= ((v & CK_INTERNAL_LOG_4) != 0) << 4;
44 r |= ((v & CK_INTERNAL_LOG_3) != 0) << 3;
45 r |= ((v & CK_INTERNAL_LOG_2) != 0) << 2;
46 r |= ((v & CK_INTERNAL_LOG_1) != 0) << 1;
47 return (r);
48 }
49
50 CK_CC_INLINE static uint32_t
ck_internal_power_2(uint32_t v)51 ck_internal_power_2(uint32_t v)
52 {
53
54 --v;
55 v |= v >> 1;
56 v |= v >> 2;
57 v |= v >> 4;
58 v |= v >> 8;
59 v |= v >> 16;
60 return (++v);
61 }
62
63 CK_CC_INLINE static unsigned long
ck_internal_max(unsigned long x,unsigned long y)64 ck_internal_max(unsigned long x, unsigned long y)
65 {
66
67 return x ^ ((x ^ y) & -(x < y));
68 }
69
70 CK_CC_INLINE static uint64_t
ck_internal_max_64(uint64_t x,uint64_t y)71 ck_internal_max_64(uint64_t x, uint64_t y)
72 {
73
74 return x ^ ((x ^ y) & -(x < y));
75 }
76
77 CK_CC_INLINE static uint32_t
ck_internal_max_32(uint32_t x,uint32_t y)78 ck_internal_max_32(uint32_t x, uint32_t y)
79 {
80
81 return x ^ ((x ^ y) & -(x < y));
82 }
83