bn2binpad
return bn2binpad(a, to, tolen, BIG, UNSIGNED);
return bn2binpad(a, to, tolen, BIG, SIGNED);
return bn2binpad(a, to, -1, BIG, UNSIGNED);
return bn2binpad(a, to, tolen, LITTLE, UNSIGNED);
return bn2binpad(a, to, tolen, LITTLE, SIGNED);