Home | History | Annotate | Line # | Download | only in libtommath 
      1 /*	$NetBSD: bn_mp_invmod.c,v 1.2 2017/01/28 21:31:47 christos Exp $	*/
      2 
      3 #include <tommath.h>
      4 #ifdef BN_MP_INVMOD_C
      5 /* LibTomMath, multiple-precision integer library -- Tom St Denis
      6  *
      7  * LibTomMath is a library that provides multiple-precision
      8  * integer arithmetic as well as number theoretic functionality.
      9  *
     10  * The library was designed directly after the MPI library by
     11  * Michael Fromberger but has been written from scratch with
     12  * additional optimizations in place.
     13  *
     14  * The library is free for all purposes without any express
     15  * guarantee it works.
     16  *
     17  * Tom St Denis, tomstdenis (at) gmail.com, http://libtom.org
     18  */
     19 
     20 /* hac 14.61, pp608 */
     21 int mp_invmod (mp_int * a, mp_int * b, mp_int * c)
     22 {
     23   /* b cannot be negative */
     24   if (b->sign == MP_NEG || mp_iszero(b) == 1) {
     25     return MP_VAL;
     26   }
     27 
     28 #ifdef BN_FAST_MP_INVMOD_C
     29   /* if the modulus is odd we can use a faster routine instead */
     30   if (mp_isodd (b) == 1) {
     31     return fast_mp_invmod (a, b, c);
     32   }
     33 #endif
     34 
     35 #ifdef BN_MP_INVMOD_SLOW_C
     36   return mp_invmod_slow(a, b, c);
     37 #else
     38   return MP_VAL;
     39 #endif
     40 }
     41 #endif
     42 
     43 /* Source: /cvs/libtom/libtommath/bn_mp_invmod.c,v  */
     44 /* Revision: 1.4  */
     45 /* Date: 2006/12/28 01:25:13  */
     46