The boot sector worm

Having a little too much spare time I started studying the PC boot-process and decided to implement a small game fitting in the boot sector on a floppy.

My main source of information for this project has been the excellent collection of texts at The Operating System Resource Center. If you are interested in this sort of low-level stuff, have a look at it.

The worm is implemented in x86 assembler and should be assembled with the nasm assembler. It should run on almost any PC-compatible computer. It uses VGA graphics mode 13h, so your computer must have a VGA card. Here's the mandatory screenshot (impressive, huh?):

News

• The placement of food is now randomized based on the number of keypresses between food movement. It seems sufficiently random.

Todo

• Reduce code size to allow further development.
• Check so that food is not placed inside the worm or on the borders.
• Add scorekeeping.
• Add comments to the code (to timer_ISR.asm in particular).

Code

Here's the code for the game, it is released under the MIT license:

• bootworm.asm
• keybd_ISR.asm
• timer_ISR.asm

If you wish to assemble the code yourself use nasm's bin outformat.

Binary

Here's the boot sector binary: bootworm.bin. To try the game place the binary in the boot sector on a floppy using an appropriate tool (e.g. dd for unix or rawrite2.exe for windows) and reboot using the floppy. By the way: use this software at your own risk. Read the license.

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Hans Wachtmeister 2002.