x32 abi support?

Gregory Maxwell gmaxwell at gmail.com
Wed May 16 14:52:54 UTC 2012


On Wed, May 16, 2012 at 10:41 AM, Jakub Jelinek <jakub at redhat.com> wrote:
> And, for various programs you usually don't need 64-bit address space,
> but in the case where you have say bigger input you are simply out of luck
> if you are limited to 32-bit address space.  Say with compilers/linkers,
> you can usually compile smaller stuff just fine with 32-bit compiler, but
> if you have some larger source code, x32 won't do it.  Similarly
> various other programs that don't have constant memory requirements, but
> linear (or worse) with the size of the input.

It's for this reason (and the multilib memory bloat) that I was really
disappointed to see x32 created.

32bit of an addressable space is a real limitation on modern machines—
and completely reasonable software which is linear in input size is
simply less useful on 32 bit machines.

If it ever comes up that Fedora wants to further limit the usability
of the i686 with older machines (e.g. by adding a SSE2 requirement),
then perhaps it would be instead better to replace i686 with x32...
but otherwise I think it would be really unfortunate to end up
subjecting fedora users to the 32bit vm limits who otherwise might not
be.


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