dropbear/libtommath/bn_mp_count_bits.c
Steffen Jaeckel b4bd23b4d2
Update LibTomMath to 1.2.0 (#84)
* update C files

* update other files

* update headers

* update makefiles

* remove mp_set/get_double()

* use ltm 1.2.0 API

* update ltm_desc

* use bundled tommath if system-tommath is too old

* XMALLOC etc. were changed to MP_MALLOC etc.
2020-05-26 23:36:47 +08:00

29 lines
576 B
C

#include "tommath_private.h"
#ifdef BN_MP_COUNT_BITS_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* returns the number of bits in an int */
int mp_count_bits(const mp_int *a)
{
int r;
mp_digit q;
/* shortcut */
if (MP_IS_ZERO(a)) {
return 0;
}
/* get number of digits and add that */
r = (a->used - 1) * MP_DIGIT_BIT;
/* take the last digit and count the bits in it */
q = a->dp[a->used - 1];
while (q > 0u) {
++r;
q >>= 1u;
}
return r;
}
#endif