microcode &lt; state machine<p>watching z80 in action is actually painful <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=DHeS6nQ_dmY" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=DHeS6nQ_dmY</a>