[x265] [EXT] Re: Compiling x265 and its Altivec code branch on Big Endian ppc64

[Guillaume POIRIER]

Hello,

On Wed, 18 Jun 2025 at 13:44, Michael Lackner
<michael.lackner at unileoben.ac.at> wrote:

> Thank you very much for your reply! In the meantime I have researched a bit, and it
> appears that "VSX" is a sub-extension that was added to Altivec with POWER7. At least
> Wikipedia says so:
>
>    https://en.wikipedia.org/wiki/AltiVec#VSX_(Vector_Scalar_Extension)
>
> According to the person who owns this specific PowerMac G5, certain older and newer
> versions of x265 *do* compile, but crash with an illegal instruction exception, indicating
> that they're attempting to execute operators that the old POWER4 chips simply don't have.

Thanks for sharing this. I clearly didn't do my homework.


> The x265 version my benchmark uses is locked to 2.5+48-bd438ce10843 for comparability reasons.

Well, that's not so bad! It's only 8 years old.


> I have talked with the person who owns the machine, and he says he might just give you
> access (via SSH), just in case you'd be willing to give this a shot.
>
> Creating such a "Big Endian POWER4" branch smells like a lot of work though...

That's a nice offer, but I don't have free time for playing with
antiquities these days...



> Also: Sad to hear you had your G5 Quad stolen. :( I also had one once, but yep, that
> liquid cooling system.. Mine ran out of liquid before I noticed, so it killed one of my
> two Laing pumps. :(

:-(

Guillaume