I'm not a native speaker, so maybe somebody else can paint a better picture. I used it just because part of my extended family comes from there (:

EDIT: s/prefix/suffix/

If one day I'll give in and take the shell out or go multi-stage, I will definitely look at that.

Maybe it's worth blogging about the journey; it's been a few weeks of merciless trade-offs to reach a usable API. It can make for a fun read (:

Thanks for taking a look!

On the former, I have no idea how to estimate BIOS functions size. Maybe I could just peek into an image and get a sense for it...

On the latter, with a 16x increase in available space, I guess I would do a much more thorough work in putting guardrails in place.

The API currently comes with a couple of traps (e.g., file names can be duplicated, processes are cooperative, all file operations perform disk I/O...) and it essentially requires guest applications to know about BIOS services in order to function.

Another sticky point I wish I had the space to address better are calling conventions, which I had to get rid of almost immediately to save on instructions.

> Thanks for pointing me towards the bosh emulator.

You're welcome! Bochs is such a nice tool which I discovered only for this project as well. It was a no-brainer, since I got no way to debug 16-bit assembly from QEMU (unless you go off and fork it[1])

[1]: https://gist.github.com/Theldus/4e1efc07ec13fb84fa10c2f3d054...

Probably a few dozen to over a hundred KB, maybe even over a MB, depending on the era of machine and what it has installed; e.g. the GPU option ROM would be included if you use int 10h, int 13h might be hooked by a disk adapter, and if you use int 16h to read from a USB keyboard, that'll go through the BIOS' USB stack which normally includes some code in SMM too.

Printing with Pascal strings is actually shorter (you skip the null test, basically), but constructing Pascal strings to pass as an argument when they are not constants yielded much more code to prepare for that call. Had I had more leeway, I would have used Pascal strings, it much less headache.

2. Files in `/bin` all include from the SDK. You can pretty much do the same for utility functions.

The includes, at least in nasm, are very much like copy-pasted code (or includes in C for that matter), and then you can just jump/call to the label.

I did not do it because I haven't been able to get nasm to optimize away the code that I don't use, and I didn't want to bloat the binaries or make a file for a 5LOC function.

All in all not good reasons in general, but it made sense to me in this context.

I thought about what would be the minimum I have to build in order to run some userland software that does "something". That to me looked like: spawn guest applications, make them persist something.

With slightly more leeway, I would probably do memory management as the next thing (besides what I mentioned in another thread here)