Mercurial > dropbear
view bn_mp_lcm.c @ 387:4663ced4968f libtommath-dropbear
propagate from branch 'au.asn.ucc.matt.ltm.orig' (head 1c2b7d389d0682caf980235dad97493e3206389c)
to branch 'au.asn.ucc.matt.ltm.dropbear' (head 40ab3795de3a6157f34e52ed3f0be3eebe9a2eaa)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 11 Jan 2007 03:13:04 +0000 |
parents | 97db060d0ef5 |
children |
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#include <tommath.h> #ifdef BN_MP_LCM_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, [email protected], http://math.libtomcrypt.com */ /* computes least common multiple as |a*b|/(a, b) */ int mp_lcm (mp_int * a, mp_int * b, mp_int * c) { int res; mp_int t1, t2; if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) { return res; } /* t1 = get the GCD of the two inputs */ if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) { goto LBL_T; } /* divide the smallest by the GCD */ if (mp_cmp_mag(a, b) == MP_LT) { /* store quotient in t2 such that t2 * b is the LCM */ if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) { goto LBL_T; } res = mp_mul(b, &t2, c); } else { /* store quotient in t2 such that t2 * a is the LCM */ if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) { goto LBL_T; } res = mp_mul(a, &t2, c); } /* fix the sign to positive */ c->sign = MP_ZPOS; LBL_T: mp_clear_multi (&t1, &t2, NULL); return res; } #endif /* $Source: /cvs/libtom/libtommath/bn_mp_lcm.c,v $ */ /* $Revision: 1.3 $ */ /* $Date: 2006/03/31 14:18:44 $ */