mp_reduce_is_2k_l.c

   1 #include "tommath_private.h"
   2 #ifdef MP_REDUCE_IS_2K_L_C
   3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
   4 /* SPDX-License-Identifier: Unlicense */
   5
   6 /* determines if reduce_2k_l can be used */
   7 bool mp_reduce_is_2k_l(const mp_int *a)
   8 {
   9    if (mp_iszero(a)) {
  10       return false;
  11    } else if (a->used == 1) {
  12       return true;
  13    } else if (a->used > 1) {
  14       /* if more than half of the digits are -1 we're sold */
  15       int ix, iy;
  16       for (iy = ix = 0; ix < a->used; ix++) {
  17          if (a->dp[ix] == MP_DIGIT_MAX) {
  18             ++iy;
  19          }
  20       }
  21       return (iy >= (a->used/2));
  22    } else {
  23       return false;
  24    }
  25 }
  26
  27 #endif