diff options
author | Matt Johnston <matt@ucc.asn.au> | 2020-10-15 19:55:15 +0800 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2020-10-15 19:55:15 +0800 |
commit | 0e3e8db5bfca0c579be55e7580a46c593c1384be (patch) | |
tree | 2b1a718f633fb95c1f2d689a591cf9e8642697f3 /libtommath/bn_s_mp_prime_is_divisible.c | |
parent | 78e17f6ee9a944430da3e517ee1fe384fd6b275b (diff) | |
parent | 17873e8c922eded2cec86184673a6d110df6403f (diff) |
merge from main
--HG--
branch : fuzz
Diffstat (limited to 'libtommath/bn_s_mp_prime_is_divisible.c')
-rw-r--r-- | libtommath/bn_s_mp_prime_is_divisible.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/libtommath/bn_s_mp_prime_is_divisible.c b/libtommath/bn_s_mp_prime_is_divisible.c new file mode 100644 index 0000000..ffd5093 --- /dev/null +++ b/libtommath/bn_s_mp_prime_is_divisible.c @@ -0,0 +1,35 @@ +#include "tommath_private.h" +#ifdef BN_S_MP_PRIME_IS_DIVISIBLE_C +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ + +/* determines if an integers is divisible by one + * of the first PRIME_SIZE primes or not + * + * sets result to 0 if not, 1 if yes + */ +mp_err s_mp_prime_is_divisible(const mp_int *a, mp_bool *result) +{ + int ix; + mp_err err; + mp_digit res; + + /* default to not */ + *result = MP_NO; + + for (ix = 0; ix < PRIVATE_MP_PRIME_TAB_SIZE; ix++) { + /* what is a mod LBL_prime_tab[ix] */ + if ((err = mp_mod_d(a, s_mp_prime_tab[ix], &res)) != MP_OKAY) { + return err; + } + + /* is the residue zero? */ + if (res == 0u) { + *result = MP_YES; + return MP_OKAY; + } + } + + return MP_OKAY; +} +#endif |