In the past month and a half, I've made some pretty major improvements: I've added CGI scripting support, so the server now supports query strings and dynamic content; and I've fully ported ymawky to run on Linux, rather than macOS-only.
In addition to GET/PUT/HEAD/DELETE/OPTIONS requests, because of CGI support ymawky also accepts POST requests (only to CGI resources for now).
I've also updated the more detailed writeup to reflect CGI support and the Linux port: https://imtomt.github.io/ymawky/
Back in the distant past I wrote some really big ARM 32 assembly projects. 64 bit ARM is really very similar!
I had a look through the code. Some ENTRY/EXIT macros to help with the drudgery of save restore registers & stack frame would probably help. Also some register renaming would help readability (eg if a register points to incoming data throughout a subroutine rename it pdata).
I salute your effort and please enjoy the core dumps :-)
Edit: or learning arm64 assembly :)
Question/critique. Isn't getting the mime type by file extension a bit windowsy? Would it not be easier to read the magic number when you're at the assembly level?