libtommath/bn_mp_reduce_is_2k_l.c
2019-05-15 09:22:36 +02:00

29 lines
678 B
C

#include "tommath_private.h"
#ifdef BN_MP_REDUCE_IS_2K_L_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* determines if reduce_2k_l can be used */
mp_bool mp_reduce_is_2k_l(const 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;
} else {
return MP_NO;
}
}
#endif