
  SPACEINV.O  -  ZX80 Space Invaders (author unknown)

  An *amazing* flicker-free game for the ZX80.
  Probably the first-ever ZX80 program in an emulator-loadable format.
  Suitable for XTender2.

  Distributed with the kind permission of Grant Searle.
  Visit his ZX80-site at http://www.babytalk.demon.co.uk/zx80/zx80.html

  To run this game in XTender2, type

        XT2=ZX80 SPACEINV

  In the ZX80, type LOAD (key W), and then RUN (key R).
  The screen will go black for a short period, then the game starts.
  Exit emulator (F1) to stop game.


  I have reverse-engineered this game, and it's a brilliant piece of
  work! It features a number of state-machines and uses time-slicing in
  such a way that each and every state in every slice consists of
  (about) the same amount of T-states, otherwise the screen will start
  shaking. You'll notice that the screen does shake a little bit
  sometimes (e.g. when the score has a carry from units to tens, or when
  a new game starts), but remember: the ZX80 does not have an
  NMI-generator, so programs like this must produce their own video and
  *meanwhile* manage the game itself (get user input, move sprites,
  detect collisions, update score, etc.). Truly unbelievable!

  Carlo Delhez, September 1998

  http://www.delhez.demon.nl/
  mailto:xtender@delhez.demon.nl

