Re: Debian ports for RiscPC, ARM710, etc.
Matthew Wilcox <Matthew.Wilcox@genedata.com> writes:
> > So I suppose we are building binaries that use the halfword
> > instructions. Is that correct?
>
> Yes. You can always objdump --disassemble |grep LDRH to check ;-)
Confirmed.
> > In the interests of portability, what would be the performance cost if
> > we somehow compiled things without the halfword instructions? Do all
> > apps benefit, or just some specific ones? Corel is using them for
> > their RPM-based distribution, so I have assumed that there is a
> > significant performance difference.
>
> I don't think there's too much of a performance issue. One or two
> additional instructions per short loaded, two extra ones per short
> stored.
Hmm. Philip thought there was a significant difference. Maybe the
best thing for me to do is to try compiling each, and do some
benchmarking.
Right now, I'm inclined to believe that the performance differential
between the new ARM stuff and the old (obsolete?) ARM stuff is large
enough to merit two binary distributions.
> > As Philip says, it would be a no-brainer to create additional
> > debian-arm distributions which have been compiled to use different
> > instruction sets, since they can share the same source (actually, all
> > Debian architectures use the same source). ie. We could have an
> > "arm-riscpc" distribution, and maybe even an "arm-710" (??)
> > distribution for older machines. Of course, this is only going to
> > happen if there is enough interest.
>
> you'd almost certainly want to use arm6 as the baseline - arm710 doesn't
> have anything that needs changing in userland.
Ok.
> > If anybody wants me to, I could build a chroot image and a set of
> > packages that have been compiled to use a different instruction set
> > and put them on my FTP site.
> >
> > Is anybody interested in such a thing? There isn't much point in me
> > doing it if nobody is going to try it, since I don't have the hardware
> > to test it on.
>
> Yes, I'm willing to test..
Great!
I'll try to have something ready by the end of the week. I want to
get glibc 2.0.96 working first (I'm having some problems with that).
Cheers,
- Jim
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