Updated Spacewar for the PDP-8/I, 8/E, etc....

[Anders Sandahl]

I used Lyle's updated version to show Spacewar on my PDP-8/a during this
weekends retro event "RetroGathering" in Sweden. It works great!

I did two modifications to the code:

1. Use digital IO instead of the switch register so I could use hand
controls to let the audience play the game.

2. Fixed a bug so that timer interrupts is turned on if the DK8-EP
programmable real time clock is used.

/Anders


>
>I just updated D.E. Wrege's Spacewar as follows:
>
>1. Correctly supports slow monitors attached to a VC8/E interface by
>correcting mistakes made in the VC8/E driver code. The code now follows
>DEC's recommended method of waiting on the VC8/E.
>
>2. Starts up with spaceships (as opposed to UFO's) per the original
>Spacewar! by Steve Russell.
>
>3. Now supports the DK8-EC Crystal Clock
>
>Items 1 & 2 were released by me previously - but support for the
>DK8-EC is brand new.
>
>The new source and listing can be picked up via anonymous FTP to
>bickleywest.com and the pdp8_spcwar directory.
>