An x86-64 back end for raven-uxn

3 days ago

The author implemented an x86-64 assembly backend for the Uxn CPU, which is twice as fast as their previous Rust implementation.
The implementation was initially written by Claude Code, an AI coding assistant, and then refined by the author.
The process involved porting 2000 lines of ARM64 assembly to x86-64, with the AI handling most of the initial translation.
The AI-assisted implementation passed unit tests and fuzzing, though it required human intervention to fix some issues.
The author improved the AI-generated assembly code, optimizing register usage and reducing unnecessary instructions.
A subtle bug was discovered during fuzzing, which was eventually traced to an out-of-bounds write in the STR instruction.
The author used Valgrind and GDB to debug the issue, a method they found more effective than printf debugging.
The final implementation was merged into the project, with the author reflecting on the role of AI in coding and debugging.
The author remains cautious about over-reliance on AI for coding but acknowledges its utility in debugging complex issues.

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