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
70
71
72
73
74
75
76
77
78
79
80
81
82
|
/* bit.c --
* Created: Thu Sep 28 18:09:30 1995 by faith@dict.org
* Copyright 1995-1996, 2002 Rickard E. Faith (faith@dict.org)
* Copyright 2002-2008 Aleksey Cheusov (vle@gmx.net)
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* \section{Bit manipulation routines}
*
* \intro These are a set of simple routine to manipulate bits in an
* integer.
*
*/
#include "maaP.h"
/* \doc Set |bit| in |flags|. */
void bit_set(unsigned long *flags, int bit)
{
*flags |= (1UL << bit);
}
/* \doc Clear |bit| in |flags|. */
void bit_clr(unsigned long *flags, int bit)
{
*flags &= ~(1UL << bit);
}
/* \doc Test |bit| in |flags|, returning non-zero if the bit is set and
zero if the bit is clear. */
int bit_tst(unsigned long *flags, int bit)
{
return (*flags & (1UL << bit));
}
/* \doc Return a count of the number of bits set in |flags|. */
int bit_cnt(unsigned long *flags)
{
unsigned long x = *flags;
#if SIZEOF_LONG == 4
x = (x >> 1 & 0x55555555) + (x & 0x55555555);
x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
x = ((x >> 4) + x) & 0x0f0f0f0f;
x = ((x >> 8) + x);
return (x + (x >> 16)) & 0xff;
#else
#if SIZEOF_LONG == 8
x = (x >> 1 & 0x5555555555555555) + (x & 0x5555555555555555);
x = ((x >> 2) & 0x3333333333333333) + (x & 0x3333333333333333);
x = ((x >> 4) + x) & 0x0f0f0f0f0f0f0f0f;
x = ((x >> 8) + x) & 0x00ff00ff00ff00ff;
x = ((x >> 16) + x) & 0x0000ffff0000ffff;
return (x + (x >> 32)) & 0xff;
#else
err_internal(__func__,
"Implemented for 32-bit and 64-bit longs, not %d-bit longs",
SIZEOF_LONG * 8);
#endif
#endif
}
|
