1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
/*-
* BSD LICENSE
*
* Copyright(c) Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "spdk/stdinc.h"
#include "spdk/util.h"
/* The following will automatically generate several version of
* this function, targeted at different architectures. This
* is only supported by GCC 6 or newer. */
#if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \
&& (defined(__i386__) || defined(__x86_64__))
__attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default")))
#endif
uint32_t
spdk_u32log2(uint32_t x)
{
if (x == 0) {
/* log(0) is undefined */
return 0;
}
return 31u - __builtin_clz(x);
}
/* The following will automatically generate several version of
* this function, targeted at different architectures. This
* is only supported by GCC 6 or newer. */
#if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \
&& (defined(__i386__) || defined(__x86_64__))
__attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default")))
#endif
uint64_t
spdk_u64log2(uint64_t x)
{
if (x == 0) {
/* log(0) is undefined */
return 0;
}
return 63u - __builtin_clzl(x);
}
|
