diff options
author | Matt Johnston <matt@ucc.asn.au> | 2007-02-03 08:20:34 +0000 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2007-02-03 08:20:34 +0000 |
commit | d9aeb2773e236e662c8b493f4bcee978f9908d7c (patch) | |
tree | bac48e388bf3ac739ae14cdf98da0eb4bb9d17bf /libtommath/bn_mp_reduce_is_2k_l.c | |
parent | 056b92bd4c8a42ce1843493310d382159166edb8 (diff) | |
parent | c5fd7dd5548f28e32d846e39d17e5c4de4e769af (diff) |
merge of '5fdf69ca60d1683cdd9f4c2595134bed26394834'
and '6b61c50f4cf888bea302ac8fcf5dbb573b443251'
--HG--
extra : convert_revision : b1dd3b94e60a07a176dba2b035ac79968595990a
Diffstat (limited to 'libtommath/bn_mp_reduce_is_2k_l.c')
-rw-r--r-- | libtommath/bn_mp_reduce_is_2k_l.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/libtommath/bn_mp_reduce_is_2k_l.c b/libtommath/bn_mp_reduce_is_2k_l.c new file mode 100644 index 0000000..c4b42c9 --- /dev/null +++ b/libtommath/bn_mp_reduce_is_2k_l.c @@ -0,0 +1,44 @@ +#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, tomstdenis@gmail.com, http://math.libtomcrypt.com + */ + +/* 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 + +/* $Source: /cvs/libtom/libtommath/bn_mp_reduce_is_2k_l.c,v $ */ +/* $Revision: 1.3 $ */ +/* $Date: 2006/03/31 14:18:44 $ */ |