title: Send interrupt to cpu as keyboard do?
body: <p>Is it possible to simulate hardware interrupts somehow from user program?
  I've seen this question posted many times, but always not answered.</p>
  
  <p>I want to know about low-level interrupts (for example simulate situation when key pressed on keyboard, so that keyboard driver would interrupt interrupt).</p>
  
  <p>High level events and APIs are outside scope, and question is rather theoretical than practical (to prevent "why" discussions :)</p>