1#include <tommath.h>
2#ifdef BN_MP_COUNT_BITS_C
3/* LibTomMath, multiple-precision integer library -- Tom St Denis
4 *
5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality.
7 *
8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place.
11 *
12 * The library is free for all purposes without any express
13 * guarantee it works.
14 *
15 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
16 */
17
18/* returns the number of bits in an int */
19int
20mp_count_bits (mp_int * a)
21{
22  int     r;
23  mp_digit q;
24
25  /* shortcut */
26  if (a->used == 0) {
27    return 0;
28  }
29
30  /* get number of digits and add that */
31  r = (a->used - 1) * DIGIT_BIT;
32
33  /* take the last digit and count the bits in it */
34  q = a->dp[a->used - 1];
35  while (q > ((mp_digit) 0)) {
36    ++r;
37    q >>= ((mp_digit) 1);
38  }
39  return r;
40}
41#endif
42
43/* $Source$ */
44/* $Revision$ */
45/* $Date$ */
46