What is the 8-bit simulator in scala compiler and

Question

I was reading this question and saw:

scalac includes an 8-bit simulator of a fully armed and operational battle station, viewable using the magic key combination CTRL-ALT-F12 during the GenICode compilation phase.

To show what compilation phases scalac has, I used scalac -Xshow-phases.

phase name  id  description
----------  --  -----------
<  ...  >
     icode  23  generate portable intermediate code

Seems to be the relevant phase.

I compile a Hello-world program

object Hello {
  def main(args: Array[String]): Unit = {
    println("Hello, world!")
  }
}

by scalac Hello.scala and pressed CTRL-ALT-F12 all the way. Nothing happened. And tried scalac -Xprint:icode Hello.scala with CTRL-ALT-F12, nothing special as well.

How can I trigger the simulator? And what does that do?

On scala 2.11.8 and OS X 10.11.5