Re: PowerPC 970 (G5) 64-bit support

[Dennis Ferguson <dennis.c.ferguson%gmail.com@localhost>]

On 11 Apr 2011, at 15:26 , Erik Fair wrote:
> Are the required changes sufficient to warrant a new port, e.g. macppc64?

There actually sort of is one: search for macppc64 in build.sh, that's
how you build a 64-bit user space.

There is the slightly different question of whether the ultimate
end state, once someone got around to completing the 64 bit support,
would need to split the powerpc directory in sys/arch in a way analogous
to i386/amd64/x86.  I don't know the answer to that, but I'm pretty
sure you wouldn't want to do that before there was someone actually
writing that code.  Right now all the 64 bit support there is exists
as #ifdef's in the files in sys/arch/powerpc/, and there's no better
place for it at the moment: the support is entirely theoretical, anyway,
so keeping it in the same files as code people actually use for something
makes it slightly more likely that there would at least be some attempt
to keep it "theoretically" up-to-date.  I'm not sure whether the
one-directory-does-both arrangement could be maintained once someone
got around to writing support for 64-bit kernel functions that don't have
equivalents in 32-bit kernels (e.g. netbsd32_* code), but it would be
better to wait and find that out from the (theoretical) person who
is trying to complete that support.

Dennis Ferguson