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Toledo Atomchess
(c) Copyright 2015-2019 Oscar Toledo G.

This Github repository contains the x86 assembler source code
for Toledo Atomchess and Toledo Atomchess Reloaded.

Toledo Atomchess allows the player to play against the computer,
the computer only plays basic legal chess movements, no promotion,
no castling and no enpassant. All this in 356 bytes bootable from
a floppy disk or 352 bytes if using the COM file. Also there is
a HACK mode version reaching 326 bytes with COM file, or 330 bytes

Toledo Atomchess Reloaded plays full chess movements and
currently sizes up to 779 bytes. It hasn't been optimized further
because of lack of time.

Check the source code for further details.

In order to assemble it, you must download the Netwide Assembler
(nasm) from

Use this command line:

  nasm -f bin toledo_atomchess.asm -o toledo_atomchess_disk.img
  nasm -f bin toledo_atomchess_reloaded.asm -o atomr.img

Or this command line for compatibility with bootOS (see my repositories):

  nasm -f bin toledo_atomchess.asm -Dbootos -o toledo_atomchess_bootos.img

It can be run with DosBox or qemu:
  qemu-system-x86_64 -fda toledo_atomchess_disk.img
  qemu-system-x86_64 -fda atomr.img

Thanks to following people:

  * HellMood for suggesting the translation of Toledo Atomchess
    to nasm syntax and some optimization suggestions.
  * Peter Ferrie (qkumba) for suggestions.
  * qu1j0t3 for providing a makefile.
  * theshich for optimization suggestions.

Enjoy it!

Useful links: 

Original homepage of Toledo Atomchess

>> 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:




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.


Toledo Atomchess is the world's smallest chess program in x86 assembly code




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