libtommath/bn_mp_get_long_long.c
Francois Perrad 556219aa5b refactor with new private macro MP_SIZEOF_BITS
CHAR_BIT is no longer directly used
2019-05-11 12:05:38 +02:00

30 lines
777 B
C

#include "tommath_private.h"
#ifdef BN_MP_GET_LONG_LONG_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* get the lower unsigned long long of an mp_int, platform dependent */
unsigned long long mp_get_long_long(const mp_int *a)
{
int i;
unsigned long long res;
if (MP_IS_ZERO(a)) {
return 0;
}
/* get number of digits of the lsb we have to read */
i = MP_MIN(a->used, (((int)MP_SIZEOF_BITS(unsigned long long) + MP_DIGIT_BIT - 1) / MP_DIGIT_BIT)) - 1;
/* get most significant digit of result */
res = (unsigned long long)a->dp[i];
#if MP_DIGIT_BIT < 64
while (--i >= 0) {
res = (res << MP_DIGIT_BIT) | (unsigned long long)a->dp[i];
}
#endif
return res;
}
#endif