_ _  _ _  _  __  ___  ____ ___   ___
 | |\ | \  / /__\ |  \ |__  |__] [__
 | | \|  \/  |  | |__/ |___ |  \ ___]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Invaders game in 512 bytes (boot sector or COM file)
by Oscar Toledo G. Jun/04/2019

http://nanochess.org
https://github.com/nanochess

This a game recreating the Invaders game in 512 bytes, that can be
run as a COM file or put into a boot sector of a floppy disk to be
run.

Move with Ctrl key to left, Alt key to right, any Shift key to
shoot. (maybe you'll need to disable StickyKeys in Windows)

The previous commit worked with left arrow, right arrow and space
key, but you had to press the space key to stop the spaceship.
Also didn't have the barriers.

Now it's compatible with 8088 (the original IBM PC) but still it
has the option for 80286 code in the source code. So you now have
to look for a 8-bit compatible VGA card if you want to run it over
original hardware ;)

A small video of the game running over emulation:

  https://www.youtube.com/watch?v=pC976eejfms

If you want to assemble it, you must download the Netwide Assembler
(nasm) from www.nasm.us

Use this command line:

  nasm -f bin invaders.asm -Dcom_file=1 -o invaders.com
  nasm -f bin invaders.asm -Dcom_file=0 -o invaders.img

Tested with VirtualBox for Mac OS X running Windows XP running this
game, it also works with DosBox and probably with qemu:

  qemu-system-x86_64 -fda invaders.img

Enjoy it!


>> THE BOOK <<        

Do you would like more details on the inner workings? This program
is fully commented in my new book Programming Boot Sector Games
and you'll also find a 8086/8088 crash course!

Now available from Lulu:

  Soft-cover
    http://www.lulu.com/shop/oscar-toledo-gutierrez/programming-boot-sector-games/paperback/product-24188564.html

  Hard-cover
    http://www.lulu.com/shop/oscar-toledo-gutierrez/programming-boot-sector-games/hardcover/product-24188530.html

  eBook
    https://nanochess.org/store.html

These are some of the example programs documented profusely
in the book:

  * Guess the number.
  * Tic-Tac-Toe game.
  * Text graphics.
  * Mandelbrot set.
  * F-Bird game.
  * Invaders game.
  * Pillman game.
  * Toledo Atomchess.
  * bootBASIC language.