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view libtommath/bn_mp_mod.c @ 1626:9bd597d29590
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author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 14 Nov 2018 22:58:35 +0800 |
parents | 8bba51a55704 |
children | f52919ffd3b1 |
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#include <tommath_private.h> #ifdef BN_MP_MOD_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://libtom.org */ /* c = a mod b, 0 <= c < b if b > 0, b < c <= 0 if b < 0 */ int mp_mod (mp_int * a, mp_int * b, mp_int * c) { mp_int t; int res; if ((res = mp_init_size (&t, b->used)) != MP_OKAY) { return res; } if ((res = mp_div (a, b, NULL, &t)) != MP_OKAY) { mp_clear (&t); return res; } if ((mp_iszero(&t) != MP_NO) || (t.sign == b->sign)) { res = MP_OKAY; mp_exch (&t, c); } else { res = mp_add (b, &t, c); } mp_clear (&t); return res; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */