s_mp_div_2d
void s_mp_div_2d(mp_int *mp, mp_digit d); /* divide by 2^d in place */
s_mp_div_2d(q, d);
s_mp_div_2d(&xc,n);
s_mp_div_2d(&yc,n);
s_mp_div_2d(&f, n);
s_mp_div_2d(x, k_orig);
s_mp_div_2d(&oddFactor, k);
s_mp_div_2d(mp, 1);
s_mp_div_2d(quot, (mp_digit)ix);
s_mp_div_2d(rem, d);
s_mp_div_2d(q, pow);
s_mp_div_2d(b, d);
s_mp_div_2d(T, mmm->b);
s_mp_div_2d(c, mmm->b);