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Diffstat (limited to 'libtommath/bn_mp_reduce_setup.c')
| -rw-r--r-- | libtommath/bn_mp_reduce_setup.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/libtommath/bn_mp_reduce_setup.c b/libtommath/bn_mp_reduce_setup.c new file mode 100644 index 0000000..5085af0 --- /dev/null +++ b/libtommath/bn_mp_reduce_setup.c @@ -0,0 +1,34 @@ +#include <tommath.h> +#ifdef BN_MP_REDUCE_SETUP_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 + */ + +/* pre-calculate the value required for Barrett reduction + * For a given modulus "b" it calulates the value required in "a" + */ +int mp_reduce_setup (mp_int * a, mp_int * b) +{ + int res; + + if ((res = mp_2expt (a, b->used * 2 * DIGIT_BIT)) != MP_OKAY) { + return res; + } + return mp_div (a, b, a, NULL); +} +#endif + +/* $Source: /cvs/libtom/libtommath/bn_mp_reduce_setup.c,v $ */ +/* $Revision: 1.3 $ */ +/* $Date: 2006/03/31 14:18:44 $ */ |