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Re: Future of m68k - Etch and beyond


On Mon, 26 Feb 2007, Wouter Verhelst wrote:

> This is a confusion in wording on my part, I'm afraid. When I say
> "classic m68k", I mean "non-coldfire m68k processors supported by
> Linux", i.e., at least the 68020 :)

Well, you seem to a have broader definition of "near-strict subset" than 

> > FP is even worse, the fp registers have different sizes, long double 
> > support is different and the fp return value is different.
> Floating point is not an exact science anyway; software which assumes it
> is, is horribly buggy and hardly portable.
> Hence, rounding differences are not critical, so long as we can define
> an ABI that adheres to the relevant standards.

The point is that you need an ABI change for this (especially for the fp 
differences) and I'm not exactly looking forward to what would 
practically be a downgrade.

> > and I wouldn't mind so much if it were an option, but I really don't like 
> > it if it's forced upon me and the whole survival of the m68k port is made 
> > dependent upon it.
> Well, at some point we will have to pick one or the other. It would be
> nice if we could support ColdFire as well as "classic" (in my above
> definition ;) m68k processors, and it would be desirable to have as
> little performance degradation as possible.
> If that turns out to be not feasible, we'll then have to decide where to
> go; the options as I see them at that point are these:
> * Go with an emulator on an amd64 machine, and hope other Debian
>   Developers want to support an architecture which from their POV only
>   exists in emulation,
> * Discontinue the port,
> * Go with ColdFire support only for Debian, and *perhaps* provide some
>   Debian derivative somewhere that will support "classic" m68k
>   processors.
> But that discussion will have to be based in data and with the option
> there for the taking.

It all depends on the place a port like m68k still has within Debian - is 
Debian willing to accommodate a port like m68k with its wellknown 
limitations. This requires of course compromises on both sides, but 
currently I don't see it. The current conditions (e.g. like required build 
speed) simply don't work for m68k and are basically intended to push out 
smaller and slower ports.
IMO this requires a discussion at large - is Debian a distribution only 
for the latest and fastest hardware or is there room for broader support 
and how could the latter look like.

bye, Roman

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