I wrote a CHIP-8 emulator in my own programming language

by pizza_man • 3 months ago

80 15 3 months ago

azhenley• 3 months ago

I wish there was a writeup about the emulator. I did find the documentation for the language: https://spectre-docs.pages.dev

Over 900 commits and 400k loc to Spectre in less than 3 weeks has me thinking this is all AI.

pizza_man2• 3 months ago

I'm not really big on blogging, but I'll write a summary of what I did, since this post seems to have gained some attention.

This is a rewrite of an emulator I wrote in Nim called Cemu, you can find the original over at https://gitlab.com/navid-m/cemu, it adds several features to the original version, including CPU speed changing with Y and H keys and a better control mapping, since the CHIP-8 ASDF controls were cumbersome for game ROMs like space invaders. It was also done as a practice to test the language for more practical applications that would involve external C libraries, in this case SDL2.

The rewrite was a good stress test for a few areas of the compiler I hadn’t exercised before, like FFI ergonomics, global handling and tooling ergonomics. Most of the core emulator logic stayed fairly close to the original, though the surrounding infrastructure (input handling, rendering loop, and timing) is cleaner and more robust now.

Overall, it’s still a fairly small project, but it served its purpose well in validating that the language can handle something more substantial, while also exposing a few rough edges that need smoothing out.

I'll address the AI claim too since you added that sneakily after I responded, I don't know where you got the number of lines from, but chances are you're taking into account the sxc.ssa file, which is just the auto-generated QBE SSA bootstrap file from the compiler, used by the install.sh script so that people can install the compiler from source without needing a prebuilt binary for their platform. No, it's clearly not AI, and if you're hellbent on saying it is, I challenge you to write any Spectre code with AI, the AI will be useless.

hotpotat• 3 months ago

Unfortunately we’re in the phase where even if you write things yourself, be it prose with em dashes or code with velocity, you’re given a demerit. And, if you are using AI, the work is still treated as less valuable, even if it brings value.

jadedtuna• 3 months ago

I'm not sure where the grandparent got 400k lines from. Perhaps total number of lines modified? I'm seeing about 115k lines, with 88k from sxc.ssa as you mentioned. Still 27k lines of code in <3 weeks is a lot, so it isn't terribly surprising that GP would assume AI given current day and age.

On that topic, I don't think GP was referring to that fact that you wrote the CHIP-8 emulator via AI, but rather that the Spectre compiler (the original Rust version) was written/augmented with AI.

Looking at the very first commits, after you've added the initial source code, there are a bunch of commits with many lines changes within the span of several minutes. Assuming not AI, I'm curious about that. Do you really just write code that quickly? Or was this a project not tracked by git originally, and you made a bunch of commits to set up some form of history for your recent changes?

flykespice• 3 months ago

Im curious, did you write a new project in a whole new language because you grew tired of Nim somehow?

Asking as someone considering nim as C/C++ replacement

oncallthrow• 3 months ago

A GitHub README.md without a torrent of AI-generated slop? Refreshing

JKCalhoun• 3 months ago

Need to write your language in the emulator—build your emulator from the language emulated in your emulator…

fouc• 3 months ago

Sounds like the Forth way.

gnabgib• 3 months ago

What was wrong with your @death_eternal account? https://news.ycombinator.com/item?id=47826806

ctenb• 3 months ago

Tangentially related, this post git me reading about the spectre language. In the spectre docs you write: "There is a notable lack of contract based programming languages that enforce correctness at a low level.". What is the difference between a function checking arguments and throwing exceptions and contract-based functions, apart from perhaps a more concise syntax to specify it?

pizza_man2• 3 months ago

The contract system allows for static propagation of trust throughout a program. If some given invariant can be assumed to hold true for the duration of a function, its clearer what can and cant happen (semantically, as opposed to doing try/catch everywhere, and then missing some blindspots, and then adding more try/catch to cover those blindspots, this is actually resolved two-fold in Spectre by using option[T]/result[T, E] on top of the trust/contract system). Moreover, type-level invariants are evaluated at compile time where possible, and non-guarded pre/postconditions are stripped from release builds for performance, meaning you can get the performance of no runtime checks and the safety guarantees (assuming you test before building with --release) provided by contracts.

Weebs• 3 months ago

Interesting language! I like the focus

I wrote a CHIP-8 emulator in my own programming language

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