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

   1 #include <tommath.h>
   2 #ifdef BN_MP_NEG_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 /* b = -a */
  19 int mp_neg (mp_int * a, mp_int * b)
  20 {
  21   int     res;
  22   if (a != b) {
  23      if ((res = mp_copy (a, b)) != MP_OKAY) {
  24         return res;
  25      }
  26   }
  27
  28   if (mp_iszero(b) != MP_YES) {
  29      b->sign = (a->sign == MP_ZPOS) ? MP_NEG : MP_ZPOS;
  30   } else {
  31      b->sign = MP_ZPOS;
  32   }
  33
  34   return MP_OKAY;
  35 }
  36 #endif
  37
  38 /* $Source: /cvs/libtom/libtommath/bn_mp_neg.c,v $ */
  39 /* $Revision: 1.3 $ */
  40 /* $Date: 2006/03/31 14:18:44 $ */