Mercurial > dropbear
view libtommath/bn_mp_reduce_is_2k_l.c @ 284:eed26cff980b
propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)
to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 08 Mar 2006 13:23:49 +0000 |
parents | |
children | 5ff8218bcee9 |
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#include <tommath.h> #ifdef BN_MP_REDUCE_IS_2K_L_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.org */ /* determines if reduce_2k_l can be used */ int mp_reduce_is_2k_l(mp_int *a) { int ix, iy; if (a->used == 0) { return MP_NO; } else if (a->used == 1) { return MP_YES; } else if (a->used > 1) { /* if more than half of the digits are -1 we're sold */ for (iy = ix = 0; ix < a->used; ix++) { if (a->dp[ix] == MP_MASK) { ++iy; } } return (iy >= (a->used/2)) ? MP_YES : MP_NO; } return MP_NO; } #endif