release/src/router/dropbear/libtommath/bn_mp_reduce_setup.c

   1 #include <tommath.h>
   2 #ifdef BN_MP_REDUCE_SETUP_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://math.libtomcrypt.com
  16  */
  17
  18 /* pre-calculate the value required for Barrett reduction
  19  * For a given modulus "b" it calulates the value required in "a"
  20  */
  21 int mp_reduce_setup (mp_int * a, mp_int * b)
  22 {
  23   int     res;
  24
  25   if ((res = mp_2expt (a, b->used * 2 * DIGIT_BIT)) != MP_OKAY) {
  26     return res;
  27   }
  28   return mp_div (a, b, a, NULL);
  29 }
  30 #endif
  31
  32 /* $Source: /cvs/libtom/libtommath/bn_mp_reduce_setup.c,v $ */
  33 /* $Revision: 1.3 $ */
  34 /* $Date: 2006/03/31 14:18:44 $ */