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Re: retrocomputing NetBSD style



At Wed, 3 Jun 2015 09:23:37 -0400 (EDT), Mouse <mouse%Rodents-Montreal.ORG@localhost> wrote:
Subject: Re: retrocomputing NetBSD style
> 
> GAW Wrote:
> > I really don't understand anyone who has the desire to try to run
> > build.sh on a VAX-750 to build even just a kernel, let alone the
> > whole distribution.
> 
> I recall a time where NetBSD/vax was broken for a long time because
> everyone was cross-building; as soon as a native build was attemped,
> the brokenness showed up.
> 
> I native build on _everything_.  If it can't native build, it isn't
> really part of my stable, so to speak.

Yes, there is that issue!

See, for instance, my recent posts comparing assembler output from
kernel compiles done by the same compiler when run on amd64 vs. i386.

However those are the kinds of bugs one might hope can be caught by
decent enough regression tests of the compiler and its toolchain.

Unfortunately these are tests which we don't have now, in part because
in a sense we treat the whole system as the regression test, thus
forcing users to do native compiles to prove there are no noticeable
regressions.

Of course if we did have a proper cross-compiler regression test suite
then we would only have to build and run such tests on those less
capable machines.

In some sense though since I don't intend to use my Soekris board (or
RPi, or BBB, etc.) as development systems, I only really care that the
cross compiler generates working code for them, and we do have an
increasingly useful whole-system regression test suite that I do intend
to run on those smaller systems to prove they work well when their
binaries have been built on my build server.

However this issue does have me wanting to do builds on my RPi and BBB
and to dig my Alpha and another Sparc server out of storage, and find a
couple of MIPS systems of each type, just so I can try cross-compiling
on them all and prove that any future fixes to the compiler will then
result in identical code no matter what host it runs on, including
self-hosted.

So, I guess until/unless we have a good compiler regression test suite
then another awesome use for older and very different hardware from the
current melange of almost-identical i386 derivatives is to help run as a
test base for the toolchain.

-- 
						Greg A. Woods
						Planix, Inc.

<woods%planix.com@localhost>       +1 250 762-7675        http://www.planix.com/

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