1 /* count-one-bits.h -- counts the number of 1-bits in a word.
2 Copyright (C) 2007-2013 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by Ben Pfaff. */
19 #ifndef COUNT_ONE_BITS_H
20 # define COUNT_ONE_BITS_H 1
25 #ifndef _GL_INLINE_HEADER_BEGIN
26 #error "Please include config.h first."
28 _GL_INLINE_HEADER_BEGIN
29 #ifndef COUNT_ONE_BITS_INLINE
30 # define COUNT_ONE_BITS_INLINE _GL_INLINE
33 /* Expand the code which computes the number of 1-bits of the local
34 variable 'x' of type TYPE (an unsigned integer type) and returns it
35 from the current function. */
36 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
37 #define COUNT_ONE_BITS(BUILTIN, TYPE) \
40 #define COUNT_ONE_BITS(BUILTIN, TYPE) \
41 /* This condition is written so as to avoid shifting by more than \
42 31 bits at once, and also avoids a random HP-UX cc bug. */ \
43 verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64 bits */ \
44 int count = count_one_bits_32 (x); \
45 if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */ \
46 count += count_one_bits_32 (x >> 31 >> 1); \
49 /* Compute and return the number of 1-bits set in the least
50 significant 32 bits of X. */
51 COUNT_ONE_BITS_INLINE int
52 count_one_bits_32 (unsigned int x)
54 x = ((x & 0xaaaaaaaaU) >> 1) + (x & 0x55555555U);
55 x = ((x & 0xccccccccU) >> 2) + (x & 0x33333333U);
56 x = (x >> 16) + (x & 0xffff);
57 x = ((x & 0xf0f0) >> 4) + (x & 0x0f0f);
58 return (x >> 8) + (x & 0x00ff);
62 /* Compute and return the number of 1-bits set in X. */
63 COUNT_ONE_BITS_INLINE int
64 count_one_bits (unsigned int x)
66 COUNT_ONE_BITS (__builtin_popcount, unsigned int);
69 /* Compute and return the number of 1-bits set in X. */
70 COUNT_ONE_BITS_INLINE int
71 count_one_bits_l (unsigned long int x)
73 COUNT_ONE_BITS (__builtin_popcountl, unsigned long int);
76 #if HAVE_UNSIGNED_LONG_LONG_INT
77 /* Compute and return the number of 1-bits set in X. */
78 COUNT_ONE_BITS_INLINE int
79 count_one_bits_ll (unsigned long long int x)
81 COUNT_ONE_BITS (__builtin_popcountll, unsigned long long int);
87 #endif /* COUNT_ONE_BITS_H */