alt.hn

6/23/2026 at 4:28:14 AM

Show HN: A pure ARM64 Assembly web server, now on Linux with CGI for no reason

 https://github.com/imtomt/ymawky/tree/linux

by imtomt

6/23/2026 at 9:43:48 AM

I love it :-)

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 :-)

by nickcw

6/23/2026 at 8:48:53 PM

Thank you! Definitely, some macros would probably be super helpful. Register renaming, too, I'm sure. When I started this project I didn't even know about register renaming lol, and at this point it's so big I'd have to dig pretty deep to find 'em all. Definitely worth doing, though, I'm sure.

by imtomt

6/23/2026 at 3:51:41 PM

RISC OS had some amazing apps written ARM26/32 -- my teenage mind was boggled

by gjvc

6/23/2026 at 1:04:43 PM

> written entirely by-hand in ARM64 assembly as a fun project. It's probably got a lot of vulnerabilities I'm unaware of

Impressive, but that second part worries me. I hope one day AI security scans upon commit (or integrated in the IDE) will alleviate that risk.

What's the current security gold standard for web servers? Hiawatha? https://hiawatha.leisink.net/

by mrbluecoat

6/23/2026 at 9:07:02 PM

Well, if security is a major concern, definitely don't use ymawky in production! That said, I did try my best to harden it. I've fuzzed the parser extensively with afl-fuzz, and got several hours without a single hang or crash. There's no major vulns I'm aware of, but in a ~4500 SLOC assembly project, there's probably gonna be some vulnerabilities that are hiding.

by imtomt

6/23/2026 at 1:46:24 PM

Hiawatha is written in C, and so despite its security posture, it probably contains vulnerabilities.

by efficax

6/23/2026 at 12:53:17 PM

Is an assembly webserver more performant than webservers written in other languages? Are there any hard limits on how much you can squeeze when using a particular framework?

by Lucasoato

6/23/2026 at 8:58:32 PM

The language matters much less than the architecture of the web server. A server written in assembly using a fork-on-request model like ymawky is going to be much slower than a server written in C using an async event loop like nginx, because forking is very inefficient at scale. Plus a big bottleneck is the networking syscalls, rather than the code itself, so two servers with the same model written in Assembly and C would likely be roughly equal.

by imtomt

6/23/2026 at 9:11:57 AM

I love projects like this because I think eventually all common computing tasks will be broken down in constituent most computationally optimized components

by hparadiz

6/23/2026 at 7:29:54 AM

This isn't a bad thing per se. I imagine this could be a thing for an embedded side project or a tiny rescue system.

Edit: or learning arm64 assembly :)

by tosti

6/23/2026 at 8:03:40 AM

Cool. I particularly like the O'Reilly book cover that never was. Although I fear you may have misunderstood what wasm is...

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?

by benj111

6/23/2026 at 2:02:19 PM

You could argue well, if you have to open the file to read it anyway may as well look for magic numbers.

That doesn't work well with text documents which won't have any kind of magic number. So now you're doing some heuristics to determine is this text/plain, text/html, text/svg? You're pretty much just guessing at that point.

A good number of file formats out there are just Zip files with a particular structure. JAR files, docx - so relying on magic numbers doesn't really work for those, either.

Also to service a HEAD request you'd have to open the file and read a few bytes that you just discard.

If you just do it by extensions you don't need to read files at all or perform heuristics, and no ambiguity for what mimetypes to use for text documents, zip-based formats, etc.

by jprjr_

6/23/2026 at 9:03:42 PM

You could do that, but it's not really necessary, and adds extra overhead and complexity. And as the other commenter pointed out, it wouldn't work for text file types without magic numbers. I considered reading the magic number at first, but after doing more research, I've found most web servers (nginx and apache, anyway) just match based on file extension. I figure if it's good enough for them, it's good enough for ymawky.

by imtomt

6/23/2026 at 8:15:35 AM

You wrote this by hand? Impressive.

by wewewedxfgdf

6/23/2026 at 11:40:09 AM

"raw syscalls only: no libc wrappers"

insane! i wonder how many times you have spent to learn about them!

by radhitya

6/23/2026 at 2:26:14 PM

Like one time? It is like any other API. You look it up, study the parameters (in this case you need to look up in which register is what argument expected) and off it goes.

by binaryturtle

6/23/2026 at 9:43:29 PM

Honestly it's easier than you'd think! All the syscall numbers are in /usr/include/asm-generic/unistd.h (on linux), and you can read the man page for any of them.

by imtomt

6/23/2026 at 8:55:28 AM

Ahh, this little gem ported to Linux, great! That opens much more possibilities to play with it, thanks

by kunley

6/23/2026 at 12:08:53 PM

arm64 is an IP-locked ISA, namely it is not worth assembly writting, stick to plain and simple C.

RISC-V is. I am self-hosting many of my internet thingies. I plan to move to RISC-V only hardware and to rewrite my internet software directly in mono-threaded paranoid RISC-V assembly.

by sylware

6/23/2026 at 9:47:35 PM

For sure. My laptop has an arm64 chip, which is why this is written in arm64. If I had an intel chip, it would be written in x86_64. RISC-V is very interesting, though, and I'd love to learn more at some point.

Good luck with your RISC-V asm stuff! Hit me up if you publish any of it :)

by imtomt

6/23/2026 at 1:53:18 PM

> arm64 is an IP-locked ISA, namely it is not worth assembly writting

Why is that a problem? Google search returns 3K page arm64 ISA manual. What else do you need to write asm?

by AntronX

6/23/2026 at 2:07:09 PM

Nothing else, I think what the're more concerned with is how open an architecture is.

I think with RISC-V if you wanted to design your own chips and stuff you can just do it, whereas ARM doesn't let you do that.

I'm not about to build my own chips so it doesn't matter all that much to me but I understand where the person is coming from. They'd rather write assembly for the more open architecture.

by jprjr_

6/23/2026 at 11:12:24 AM

There's critical security flaws in this web server. Consult your local LLM for a security analysis.

by wewewedxfgdf