Altivec Context Management

Ralf Corsepius ralf.corsepius at rtems.org
Fri Nov 4 15:03:28 UTC 2005


On Fri, 2005-11-04 at 08:16 -0600, Joel Sherrill  wrote:

> + Add Altivec multilib
> 
>    If we have extra registers which gcc is aware of, this forces our hand
>    and it adds a multilib.
We already have this multilib.

-mcpu=7400 implies altivec, all others don't.

I.e. if -maltivec is a problem to RTEMS and some BSPs, you should use a
different -mcpu=<cpu>. If this is not possible, the powerpc port in
RTEMS is facing a the limitations of its design.

IMO, a separate -maltivec multilib variant doesn't make without a major
redesign of the powerpc port. 

>    Whether this should be done for 4.6 tools is up for discussion but it
>    is clear that gcc 4.0.x and newer definitely will have to ship with
>    Altivec multilibs for RTEMS.

cf. above.

Ralf






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