diff options
Diffstat (limited to 'libtommath/bn_mp_reduce_2k_setup_l.c')
-rw-r--r-- | libtommath/bn_mp_reduce_2k_setup_l.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/libtommath/bn_mp_reduce_2k_setup_l.c b/libtommath/bn_mp_reduce_2k_setup_l.c new file mode 100644 index 0000000..810a456 --- /dev/null +++ b/libtommath/bn_mp_reduce_2k_setup_l.c @@ -0,0 +1,40 @@ +#include <tommath.h> +#ifdef BN_MP_REDUCE_2K_SETUP_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@iahu.ca, http://math.libtomcrypt.org + */ + +/* determines the setup value */ +int mp_reduce_2k_setup_l(mp_int *a, mp_int *d) +{ + int res; + mp_int tmp; + + if ((res = mp_init(&tmp)) != MP_OKAY) { + return res; + } + + if ((res = mp_2expt(&tmp, mp_count_bits(a))) != MP_OKAY) { + goto ERR; + } + + if ((res = s_mp_sub(&tmp, a, d)) != MP_OKAY) { + goto ERR; + } + +ERR: + mp_clear(&tmp); + return res; +} +#endif |