Far-calling from NASM source to C results in "error: ELF format does not support segment base references"

[ecm-pushbx]

This is a NASM feature request I submitted, to support calling C functions far with immediate calls from NASM: https://bugzilla.nasm.us/show_bug.cgi?id=3392694

[tkchia]

Hello @ecm-pushbx,

Yes, and sorry for the belated reply.

Well, there is no official support yet for IA-16 segment relocations in the ELF file format, and the actual relocation support I implemented into the gcc-ia16 toolchain is rather hacky.

A while back Mr. Anvin (nasm maintainer) actually proposed a way to represent IA-16 segment:offset addresses, which is more rigorous and flexible than the current default method. But there are a few problems:

• it is incompatible with the current scheme (which is used by existing code, e.g. the FreeDOS kernel), and
• Mr. Anvin has not really implemented the new method in nasm yet, as far as I know.

I wrote a brief write-up to summarize the situation.

So the situation with segment relocations in ELF object files is kind of messy, and I am not sure what the best way forward is.

Thank you!

(Edited to add: related discussion at a separate Bugzilla thread.)

[ecm-pushbx]

Two of your links lead to the same document.

[tkchia]

(@ecm-pushbx : corrected; thanks!)

[roytam1]

nasm bugzilla seems down