I'm wondering if you can build an actual "Linux from scratch" with this as the lowest level, without the need to use a host system at all.
There's something to be said for taking advantage of that existing code; but if that's a dependency it should be part of the environment manifest. Everything has (most things have) a context where it might be useful and that should be included in the explanation so a tool isn't misused and so incorrect expectations aren't set.
I would have preferred 32-bit mode because real mode is awkward with its seg:off addressing scheme.
Using the bios functions just allows it to have “not-boring” examples easily.
Perhaps with a few more "layers of compilers" on top you can get a very early GCC going.
Applause. Best comment ;)
The problem is not just declaring structs but accessing them, referencing them, accessing/referencing fields and subfields, etc. That has to all be in the syntax. For such a minimal project you can ignore initialization.
I did all this while adding maybe 500 lines of C to GitHub.com/vitiral/fngi. Never tried for this level of minimalism though.
[1]: This is why all of the names of struct members in unix are "needlessly" prefixed; i.e. struct stat.st_mode is not struct stat.mode because that could conflict with struct foo.mode until the early 1980s.