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77 lines
2.7 KiB
C
77 lines
2.7 KiB
C
/* count-one-bits.h -- counts the number of 1-bits in a word.
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Copyright (C) 2007-2008 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Written by Ben Pfaff. */
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#ifndef COUNT_ONE_BITS_H
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# define COUNT_ONE_BITS_H 1
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#include <stdlib.h>
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#include "verify.h"
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/* Expand the code which computes the number of 1-bits of the local
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variable 'x' of type TYPE (an unsigned integer type) and returns it
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from the current function. */
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#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
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#define COUNT_ONE_BITS(BUILTIN, TYPE) \
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return BUILTIN (x);
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#else
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#define COUNT_ONE_BITS(BUILTIN, TYPE) \
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/* This condition is written so as to avoid shifting by more than \
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31 bits at once, and also avoids a random HP-UX cc bug. */ \
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verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64 bits */ \
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int count = count_one_bits_32 (x); \
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if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */ \
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count += count_one_bits_32 (x >> 31 >> 1); \
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return count;
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/* Compute and return the the number of 1-bits set in the least
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significant 32 bits of X. */
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static inline int
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count_one_bits_32 (unsigned int x)
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{
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x = ((x & 0xaaaaaaaaU) >> 1) + (x & 0x55555555U);
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x = ((x & 0xccccccccU) >> 2) + (x & 0x33333333U);
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x = (x >> 16) + (x & 0xffff);
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x = ((x & 0xf0f0) >> 4) + (x & 0x0f0f);
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return (x >> 8) + (x & 0x00ff);
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}
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#endif
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/* Compute and return the number of 1-bits set in X. */
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static inline int
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count_one_bits (unsigned int x)
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{
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COUNT_ONE_BITS (__builtin_popcount, unsigned int);
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}
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/* Compute and return the number of 1-bits set in X. */
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static inline int
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count_one_bits_l (unsigned long int x)
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{
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COUNT_ONE_BITS (__builtin_popcountl, unsigned long int);
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}
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#if HAVE_UNSIGNED_LONG_LONG_INT
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/* Compute and return the number of 1-bits set in X. */
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static inline int
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count_one_bits_ll (unsigned long long int x)
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{
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COUNT_ONE_BITS (__builtin_popcountll, unsigned long long int);
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}
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#endif
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#endif /* COUNT_ONE_BITS_H */
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