#include "tommath_private.h" #ifdef BN_MP_GET_BIT_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. */ /* Checks the bit at position b and returns MP_YES if the bit is 1, MP_NO if it is 0 and MP_VAL in case of error */ int mp_get_bit(const mp_int *a, int b) { int limb; mp_digit bit, isset; if (b < 0) { return MP_VAL; } limb = b / DIGIT_BIT; bit = (mp_digit)1 << ((mp_digit)b % DIGIT_BIT); isset = a->dp[limb] & bit; return (isset != 0) ? MP_YES : MP_NO; } #endif