kc3-lang/gnulib/lib/count-one-bits.h

• Show log

  Commit

• Hash : d60f3b0c
  Author :
  Date : 2011-01-01T20:17:23
  

  maint: update almost all copyright ranges to include 2011
  
  Run the new "make update-copyright" rule.
  

Download

• lib/count-one-bits.h

• /* count-one-bits.h -- counts the number of 1-bits in a word.
     Copyright (C) 2007-2011 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  /* Written by Ben Pfaff.  */
  
  #ifndef COUNT_ONE_BITS_H
  # define COUNT_ONE_BITS_H 1
  
  #include <stdlib.h>
  #include "verify.h"
  
  /* Expand the code which computes the number of 1-bits of the local
     variable 'x' of type TYPE (an unsigned integer type) and returns it
     from the current function.  */
  #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
  #define COUNT_ONE_BITS(BUILTIN, TYPE)              \
          return BUILTIN (x);
  #else
  #define COUNT_ONE_BITS(BUILTIN, TYPE)                                       \
          /* This condition is written so as to avoid shifting by more than   \
             31 bits at once, and also avoids a random HP-UX cc bug.  */      \
          verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64 bits */ \
          int count = count_one_bits_32 (x);                                  \
          if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */          \
            count += count_one_bits_32 (x >> 31 >> 1);                        \
          return count;
  
  /* Compute and return the the number of 1-bits set in the least
     significant 32 bits of X. */
  static inline int
  count_one_bits_32 (unsigned int x)
  {
    x = ((x & 0xaaaaaaaaU) >> 1) + (x & 0x55555555U);
    x = ((x & 0xccccccccU) >> 2) + (x & 0x33333333U);
    x = (x >> 16) + (x & 0xffff);
    x = ((x & 0xf0f0) >> 4) + (x & 0x0f0f);
    return (x >> 8) + (x & 0x00ff);
  }
  #endif
  
  /* Compute and return the number of 1-bits set in X. */
  static inline int
  count_one_bits (unsigned int x)
  {
    COUNT_ONE_BITS (__builtin_popcount, unsigned int);
  }
  
  /* Compute and return the number of 1-bits set in X. */
  static inline int
  count_one_bits_l (unsigned long int x)
  {
    COUNT_ONE_BITS (__builtin_popcountl, unsigned long int);
  }
  
  #if HAVE_UNSIGNED_LONG_LONG_INT
  /* Compute and return the number of 1-bits set in X. */
  static inline int
  count_one_bits_ll (unsigned long long int x)
  {
    COUNT_ONE_BITS (__builtin_popcountll, unsigned long long int);
  }
  #endif
  
  #endif /* COUNT_ONE_BITS_H */
  

Download