crypto/external/bsd/heimdal/dist/lib/hcrypto/libtommath/bn_mp_lcm.c

   1 /*      $NetBSD: bn_mp_lcm.c,v 1.1.1.2 2014/04/24 12:45:31 pettai Exp $ */
   2
   3 #include <tommath.h>
   4 #ifdef BN_MP_LCM_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@gmail.com, http://libtom.org
  18  */
  19
  20 /* computes least common multiple as |a*b|/(a, b) */
  21 int mp_lcm (mp_int * a, mp_int * b, mp_int * c)
  22 {
  23   int     res;
  24   mp_int  t1, t2;
  25
  26
  27   if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) {
  28     return res;
  29   }
  30
  31   /* t1 = get the GCD of the two inputs */
  32   if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) {
  33     goto LBL_T;
  34   }
  35
  36   /* divide the smallest by the GCD */
  37   if (mp_cmp_mag(a, b) == MP_LT) {
  38      /* store quotient in t2 such that t2 * b is the LCM */
  39      if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) {
  40         goto LBL_T;
  41      }
  42      res = mp_mul(b, &t2, c);
  43   } else {
  44      /* store quotient in t2 such that t2 * a is the LCM */
  45      if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) {
  46         goto LBL_T;
  47      }
  48      res = mp_mul(a, &t2, c);
  49   }
  50
  51   /* fix the sign to positive */
  52   c->sign = MP_ZPOS;
  53
  54 LBL_T:
  55   mp_clear_multi (&t1, &t2, NULL);
  56   return res;
  57 }
  58 #endif
  59
  60 /* Source: /cvs/libtom/libtommath/bn_mp_lcm.c,v  */
  61 /* Revision: 1.4  */
  62 /* Date: 2006/12/28 01:25:13  */