#include <tommath.h>#ifdef BN_MP_MOD_2D_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, tomstdenis@iahu.ca, http://math.libtomcrypt.org *//* calc a value mod 2**b */intmp_mod_2d (mp_int * a, int b, mp_int * c){  int     x, res;  /* if b is <= 0 then zero the int */  if (b <= 0) {    mp_zero (c);    return MP_OKAY;  }  /* if the modulus is larger than the value than return */  if (b >= (int) (a->used * DIGIT_BIT)) {    res = mp_copy (a, c);    return res;  }  /* copy */  if ((res = mp_copy (a, c)) != MP_OKAY) {    return res;  }  /* zero digits above the last digit of the modulus */  for (x = (b / DIGIT_BIT) + ((b % DIGIT_BIT) == 0 ? 0 : 1); x < c->used; x++) {    c->dp[x] = 0;  }  /* clear the digit that is not completely outside/inside the modulus */  c->dp[b / DIGIT_BIT] &=    (mp_digit) ((((mp_digit) 1) << (((mp_digit) b) % DIGIT_BIT)) - ((mp_digit) 1));  mp_clamp (c);  return MP_OKAY;}#endif