Show HN: A Sinclair ZX81 retro web assembler+simulator

1 day ago

Lots of fun to do. I would have not taken the time without the speedup provided by Claude.

https://andyrosa.github.io/Sinclaude/simulator.html

I still have my zx-81, it powers up but the keyboard membrane is long gone. Learnt z80 assembly on it. Good times.

  • ZX Renew sells replacement membranes for £12 if you want to get it in working order.

  • I have my ZX-81 (with the 16KB expansion pack) and my ZX-Spectrum (with a microdrive). I think they're in working condition though they haven't been powered up like in 30+ years.

    • Watching the retrocomputing enthusiasts, apart from obvious things like water damage, it seems that the first thing that one always has to check before attempting to power up is capacitors. A generalism true for all old electronics, rather than Sinclair-specific.

      1 reply →

Can you say what parts Claude was used for to speed this up?

  • My guess is most of it? This commit message for example sounds very much like a Claude result:

        Add Space Invaders game implementation in assembly language
        - Implemented the core game logic including player movement, missile firing, and invader behavior.
        - Added collision detection for missiles and bombs.
        - Included game state management for win/lose conditions and restarting the game.
        - Created functions for drawing game elements on the screen and handling keyboard input.
        - Defined constants and variables for game configuration and state tracking.
    
    

    That last one in particular is exactly the kind of update you get from claude, it doesn't sound very human. "Constants and variables" eh? Not just constants or variables, but constants and variables.

    Helpful, but not. Detailed, but not.

    • rule #1 of ai programming: read and approve everything before accept. rule #2 do not let it write commit messages - i did not know notice that until many commits later. they are horrible. change 10 things - writes about the last one, too peppy too.

The ZX81 did not have a copyright on boot.

  • An interesting observation. It prompts the thought of how far away this simulator is from an actual ZX81, and how much it has been pulled away from a ZX81 by dint of training data where simulated retrocomputers of other types all boot into copyright messages. I wonder how often the spicy autocomplete engine tried to make it put up a "READY" or "OK" prompt.

    One ZX81 clone actually did have a "READY" prompt, I read. Actual intelligence was doing the same in the 1980s. (-: