BN_mod_lshift_quick
ret = BN_mod_lshift_quick(r, r, n, (abs_m ? abs_m : m));
if (!BN_mod_lshift_quick(n2, n2, 2, p))
if (!BN_mod_lshift_quick(n3, n0, 3, p))
int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m);