Bug#701561: Please test ioquake3 on PowerPC, particularly without Altivec

[thinkbrown at gmail.com]

On Tue, Jun 4, 2013 at 9:58 AM, Simon McVittie <smcv at debian.org> wrote:
> On 04/06/13 13:58, thinkbrown at gmail.com wrote:
>> One thing I'd suggest is that
>> altivec is enabled based on the CPU itself, and not just PPC vs PPC64.
>
> Sorry, I'm not going to do significant development on this myself, but
> if you or another powerpc porter want to put a patchset together,
> upstream would probably take it.  There seems to be some support for
> runtime detection already, but AIUI, compiling the whole thing with
> -maltivec means that's useless, because gcc is within its rights to emit
> Altivec instructions anyway?
>
> Another possibility would be to have a separate "lowest common
> denominator" Q3 binary for PowerPC-without-Altivec, and have it
> transparently exec the Altivec binary (with the same command line) if it
> determines that we do actually have Altivec. It would probably need to
> behave like its own mini-architecture within the Quake 3 engine, with a
> separate suffix or directory for loadable modules (perhaps *ppc.so for
> Altivec and *oldppc.so for non-Altivec?)
>
> What I'm more concerned about is whether the PowerPC JIT for the Quake 3
> bytecode language (code/qcommon/vm_powerpc*) emits Altivec opcodes - I
> have no idea how I'd determine that. That's why I'm specifically asking
> for testing with the bytecode game logic.

I did some tinkering with runtime detection when I was working on
getting PPC64 support under Quake II, so I'll see if I can make
something work. Maybe  *ppcaltivec.so, *ppc.so, and *ppc64.so

>
>> Is Rage128 still a supported 3D accelerator? I know it'll be slow as
>> heck, but it's the only card I have for my PowerMac G3s.
>
> Your guess is as good as mine :-)
>
> If all G3s are likely to be this low-spec, perhaps ioquake3/powerpc
> should just continue to require Altivec, and put a note in xmessage(1)
> on older machines...

Yeah, for the most part, non-altivec PPC/PPCSPE machines are probably
going to be incapable of running Quake III at a reasonable speed.
AFAIK, the highest end PCI card that there's a Macintosh ROM for is
the Radeon 7000.


I'll see if I can get a build machine up later today, since actually
compiling on a G3 would be exceptionally slow.


Logan