1 /* count-one-bits.h -- counts the number of 1-bits in a word.
2 Copyright (C) 2007-2008 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 Lesser 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 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser 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 /* Expand the code which computes the number of 1-bits of the local
26 variable 'x' of type TYPE (an unsigned integer type) and returns it
27 from the current function. */
28 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
29 #define COUNT_ONE_BITS(BUILTIN, TYPE) \
32 #define COUNT_ONE_BITS(BUILTIN, TYPE) \
33 /* This condition is written so as to avoid shifting by more than \
34 31 bits at once, and also avoids a random HP-UX cc bug. */ \
35 verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64 bits */ \
36 int count = count_one_bits_32 (x); \
37 if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */ \
38 count += count_one_bits_32 (x >> 31 >> 1); \
41 /* Compute and return the the number of 1-bits set in the least
42 significant 32 bits of X. */
44 count_one_bits_32 (unsigned int x
)
46 x
= ((x
& 0xaaaaaaaaU
) >> 1) + (x
& 0x55555555U
);
47 x
= ((x
& 0xccccccccU
) >> 2) + (x
& 0x33333333U
);
48 x
= (x
>> 16) + (x
& 0xffff);
49 x
= ((x
& 0xf0f0) >> 4) + (x
& 0x0f0f);
50 return (x
>> 8) + (x
& 0x00ff);
54 /* Compute and return the number of 1-bits set in X. */
56 count_one_bits (unsigned int x
)
58 COUNT_ONE_BITS (__builtin_popcount
, unsigned int);
61 /* Compute and return the number of 1-bits set in X. */
63 count_one_bits_l (unsigned long int x
)
65 COUNT_ONE_BITS (__builtin_popcountl
, unsigned long int);
68 #if HAVE_UNSIGNED_LONG_LONG_INT
69 /* Compute and return the number of 1-bits set in X. */
71 count_one_bits_ll (unsigned long long int x
)
73 COUNT_ONE_BITS (__builtin_popcountll
, unsigned long long int);
77 #endif /* COUNT_ONE_BITS_H */