I wrote a Pong game in a 512-byte boot sector

(akshatjoshi.com)

87 points | by akshat666 4 days ago

10 comments

  • akshat666 4 days ago
    Built this as a personal challenge. No OS, no drivers — just x86 assembly and BIOS. 512 bytes exactly. Boots in QEMU.

    Run it: nasm -f bin pong.asm -o boot.bin qemu-system-x86_64 boot.bin

    GitHub: https://github.com/akshat666/-bootponggame

  • amiga386 5 hours ago
    "No operating system. [...] Just [...] BIOS". Hmm.

    Out of interest, is there a difference in environment between running a COM executable for MS-DOS versus running a bootblock? I know there's the whole of MS-DOS, but a typical size-coded demo (http://www.sizecoding.org/wiki/DOS) will only use int 10h to switch mode, and that's it. Everything else is IO mapped (e.g. the keyboard) or memory mapped (e.g. screen memory). Could these equally run as a bootblock, and vice-versa?

    One difference I know of is that DOS maintains an ever-increasing timer that it writes to 0:046C... is that available at bootblock execution time?

    • CrociDB 2 hours ago
      As far as I know yes, but with some minor changes, like the the position to be loaded in memory (`org 0x7c00` for bootloaders and I think `org 0x100` for DOS) and the fact that it needs to be exactly 512bytes to boot.
  • joenot443 7 hours ago
    This is cool!

    BTW I checked out your Github and tried the link to your personal site - looks like the www prefix isn't working.

    www.akshatjoshi.com fails but akshatjoshi.com works. Gotta fix those A records!

  • kragen 6 hours ago
    Possibly relevant is hugi-compo round 3, the "Pong" compo: https://www.hugi.scene.org/compo/compoold.htm#compo3

    I spent three days disassembling Guillermo Sais's 142-byte winner, which was challenging to understand. My notes may be of interest; they are in gsais-pong.md in http://canonical.org/~kragen/sw/pavnotes2.git/

    I hope this is not interpreted as any kind of criticism. I would much rather be responsible for maintaining Joshi's code than Sais's. But I suspect that most people who are interested in either work will be interested in the other.

  • matsz 9 hours ago
    It's probably one of the best introductory projects to x86 assembly on bare metal.

    More advanced than my attempt: https://github.com/mat-sz/pongloader

    BTW: You could provide a live online demo using v86 - https://github.com/copy/v86

  • mg794613 3 hours ago
    Tomorrow it's my turn to pretend to have written this!
  • Barry-Perkins 3 hours ago
    Pong in 512 bytes — boot, play, amaze
  • 110111011110 5 hours ago
    always facinated by these.

    some ideas: - could try to add another player. just need to map 4 more keys. IO should be fine doing it the same way (dont think itd need thread or whatever) the io is super fast in the qemu scenario.

    - rather than have this in the MBR. make an MBR where you can select this sector to load as next sector and jump, maybe even with ability to return. *you can then expose other games too if ud ever be bothered for snake or minesweeper :D

    just some tinkering ideas. cool project and hats off. its always more tricky than it looks these things!

  • anthk 8 hours ago
    Now that I see this, I'd curious if something like Nethack 3.4.3 or Slashem could be rewritten in T3X0 and be playable under 286 machines:

    https://t3x.org/t3x/0/

    There's a working Rogue port for Minix2 under a 16 bit CPU (and for the Z Machine too, and GBA, and several others...), but I think even Hack 1.0.3 would be too big to fit under a 286 with 640k.

    It would be a good start if Nethack 1.3d got working under CP/M for instance, rewritten with T3X0 and some ASM hacks for speeds...

    • fl7305 7 hours ago
      You could easily write a RISC-V CPU emulator for your older/smaller machines, and run the original Nethack code compiled to RISC-V.
      • anthk 3 hours ago
        Under a 286? At time-freezing speeds. Minix 2 under a homebrew 16 bit CPU already was so-so in usability:

        https://homebrewcpu.com/

  • Andrew-Tate 2 hours ago
    [flagged]