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d7014610 LC |
1 | /* count-one-bits.h -- counts the number of 1-bits in a word. |
2 | Copyright (C) 2007-2008 Free Software Foundation, Inc. | |
3 | ||
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. | |
8 | ||
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. | |
13 | ||
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/>. */ | |
16 | ||
17 | /* Written by Ben Pfaff. */ | |
18 | ||
19 | #ifndef COUNT_ONE_BITS_H | |
20 | # define COUNT_ONE_BITS_H 1 | |
21 | ||
22 | #include <stdlib.h> | |
23 | #include "verify.h" | |
24 | ||
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) \ | |
30 | return BUILTIN (x); | |
31 | #else | |
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); \ | |
39 | return count; | |
40 | ||
41 | /* Compute and return the the number of 1-bits set in the least | |
42 | significant 32 bits of X. */ | |
43 | static inline int | |
44 | count_one_bits_32 (unsigned int x) | |
45 | { | |
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); | |
51 | } | |
52 | #endif | |
53 | ||
54 | /* Compute and return the number of 1-bits set in X. */ | |
55 | static inline int | |
56 | count_one_bits (unsigned int x) | |
57 | { | |
58 | COUNT_ONE_BITS (__builtin_popcount, unsigned int); | |
59 | } | |
60 | ||
61 | /* Compute and return the number of 1-bits set in X. */ | |
62 | static inline int | |
63 | count_one_bits_l (unsigned long int x) | |
64 | { | |
65 | COUNT_ONE_BITS (__builtin_popcountl, unsigned long int); | |
66 | } | |
67 | ||
68 | #if HAVE_UNSIGNED_LONG_LONG_INT | |
69 | /* Compute and return the number of 1-bits set in X. */ | |
70 | static inline int | |
71 | count_one_bits_ll (unsigned long long int x) | |
72 | { | |
73 | COUNT_ONE_BITS (__builtin_popcountll, unsigned long long int); | |
74 | } | |
75 | #endif | |
76 | ||
77 | #endif /* COUNT_ONE_BITS_H */ |