1 /* -*- c++ -*- */
2 /*
3 * Copyright 2003,2013 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
10 * any later version.
11 *
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
21 */
22
23 #include <gnuradio/blocks/count_bits.h>
24
25 /*
26 * these are slow and obvious. If you need something faster, fix these
27 *
28 * Can probably replace with VOLK's popcount
29 */
30
31 namespace gr {
32 namespace blocks {
33
count_bits8(unsigned int x)34 unsigned int count_bits8(unsigned int x)
35 {
36 int count = 0;
37
38 for (int i = 0; i < 8; i++) {
39 if (x & (1 << i))
40 count++;
41 }
42
43 return count;
44 }
45
count_bits16(unsigned int x)46 unsigned int count_bits16(unsigned int x)
47 {
48 int count = 0;
49
50 for (int i = 0; i < 16; i++) {
51 if (x & (1 << i))
52 count++;
53 }
54
55 return count;
56 }
57
count_bits32(unsigned int x)58 unsigned int count_bits32(unsigned int x)
59 {
60 unsigned res = (x & 0x55555555) + ((x >> 1) & 0x55555555);
61 res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
62 res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
63 res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
64 return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
65 }
66
count_bits64(unsigned long long x)67 unsigned int count_bits64(unsigned long long x)
68 {
69 return count_bits32((x >> 32) & 0xffffffff) + count_bits32(x & 0xffffffff);
70 }
71
72 } /* namespace blocks */
73 } /* namespace gr */
74