libtommath/mp_reduce_is_2k_l.c
2019-11-11 21:52:20 +01:00

28 lines
660 B
C

#include "tommath_private.h"
#ifdef 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 */
bool mp_reduce_is_2k_l(const mp_int *a)
{
if (mp_iszero(a)) {
return false;
} else if (a->used == 1) {
return true;
} else if (a->used > 1) {
/* if more than half of the digits are -1 we're sold */
int ix, iy;
for (iy = ix = 0; ix < a->used; ix++) {
if (a->dp[ix] == MP_DIGIT_MAX) {
++iy;
}
}
return (iy >= (a->used/2));
} else {
return false;
}
}
#endif