bn_mp_count_bits.c

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Author : Francois Perrad
Date : 2017-10-15 19:58:35
Hash : f1d6c887
Message : refactor cast

bn_mp_count_bits.c

#include <tommath_private.h>
#ifdef BN_MP_COUNT_BITS_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was designed directly after the MPI library by
 * Michael Fromberger but has been written from scratch with
 * additional optimizations in place.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, tstdenis82@gmail.com, http://libtom.org
 */

/* returns the number of bits in an int */
int mp_count_bits(const mp_int *a)
{
   int     r;
   mp_digit q;

   /* shortcut */
   if (a->used == 0) {
      return 0;
   }

   /* get number of digits and add that */
   r = (a->used - 1) * DIGIT_BIT;

   /* take the last digit and count the bits in it */
   q = a->dp[a->used - 1];
   while (q > (mp_digit)0) {
      ++r;
      q >>= (mp_digit)1;
   }
   return r;
}
#endif

/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */

kc3-lang/libtommath/bn_mp_count_bits.c

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