Zfbfinxmin extension?

[asb]

All of the existing floating point extensions have a *inx variant (zfinx, zdinx, zhinx, and zhinxmin). Do you plan to define one for for zfbfinxmin?

[kdockser]

It would be good to have an zfbfinxmin extension. However, creating such an extension was under the preview of the Zfinx Task Group. Since that group has been dissolved, it is probably up to the Unprivileged Architecture Standing Committee.

[asb]

Thanks for the response Ken. I have zero personal interest in zfbfinxmin, but it does feel like it would be a more efficient use of everyone's time if zfbfinxmin were defined alongside the other extensions, now that (for better or worse) the precedent has been set that floating point extensions should have an *inx variant. It sounds like the alternative might leave such a gap for an extended time, given there's no clear working group to champion the proposal? That said, I've not been directly involved in the current version of the RISC-V ISA standard tracks so perhaps my assessment is wrong there?

I've drafted a PR that adds such an extension. #31

[kdockser]

Hi Alex. Thanks so much for your enthusiasm!

While I agree with you that such an extension makes sense, I do not believe zfbfinxmin belongs in the BF16 extensions specification, but rather in the zfinx extensions specification where all of the other "inx" extensions reside. Perhaps you could submit a pull request there.

Thanks,
Ken

[asb]

I don't want to put undue burden on this effort - but as you said, the zfinx extension task group has been dissolved. The zfinx repo is dead as the spec has been merged into the riscv-isa-manual, and it doesn't seem appropriate to submit zfbfinx against riscv-isa-manual.

I do think it would be better if the package of extensions that get proposed for ratification includes zfbfinxmin rather than leaving the gap to be fixed later, and I would have thought having the extension defined within this repo is the only way of achieving that. But if there's no appetite for it, I'm happy enough to leave it.

[kdockser]

I'm looking into this.