Mercurial > dropbear
diff bn_mp_mod.c @ 1:22d5cf7d4b1a libtommath
Renaming branch
author | Matt Johnston <matt@ucc.asn.au> |
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date | Mon, 31 May 2004 18:23:46 +0000 |
parents | |
children | d29b64170cf0 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/bn_mp_mod.c Mon May 31 18:23:46 2004 +0000 @@ -0,0 +1,42 @@ +/* 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.org + */ +#include <tommath.h> + +/* c = a mod b, 0 <= c < b */ +int +mp_mod (mp_int * a, mp_int * b, mp_int * c) +{ + mp_int t; + int res; + + if ((res = mp_init (&t)) != MP_OKAY) { + return res; + } + + if ((res = mp_div (a, b, NULL, &t)) != MP_OKAY) { + mp_clear (&t); + return res; + } + + if (t.sign != b->sign) { + res = mp_add (b, &t, c); + } else { + res = MP_OKAY; + mp_exch (&t, c); + } + + mp_clear (&t); + return res; +}