lib/hcrypto/libtommath/bn_s_mp_get_bit.c

   1 #include "tommath_private.h"
   2 #ifdef BN_S_MP_GET_BIT_C
   3
   4 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
   5 /* SPDX-License-Identifier: Unlicense */
   6
   7 /* Get bit at position b and return MP_YES if the bit is 1, MP_NO if it is 0 */
   8 mp_bool s_mp_get_bit(const mp_int *a, unsigned int b)
   9 {
  10    mp_digit bit;
  11    int limb = (int)(b / MP_DIGIT_BIT);
  12
  13    if (limb >= a->used) {
  14       return MP_NO;
  15    }
  16
  17    bit = (mp_digit)1 << (b % MP_DIGIT_BIT);
  18    return ((a->dp[limb] & bit) != 0u) ? MP_YES : MP_NO;
  19 }
  20
  21 #endif