Re: AVX on Cygwin

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Nov 27 22:28, Achim Gratz wrote:
> Corinna Vinschen writes:
> > On second thought, what I'm wondering about is what exactly *is* the
> > problem with AVX?  While the AVX context isn't saved when running signal
> > handlers or getcontext, it's very unlikely that the AVX state changes at
> > all when running a system function or signal handler.  No system function
> > in Cygwin affects the AVX registers.  And a signal handler running AVX
> > functions seems unlikely, too.
> 
> I've tried to figure something out from the strace that was posted on
> the main list, but I don't see anything (it's big and I may have missed
> it).
> 
> > Before changing Cygwin it would be nice to know exactly where/when the
> > problem occurs.
> 
> Please don't change anything yet.  I've read the release notes again,
> the thing specific to Broadwell/Skylake are the two ADX instructions,
> which should be using plain 64bit registers.  For whatever reason these
> two architectures have special treatment only on 64bit and are ignored
> for 32bit if I read things correctly in the source.

Ok, but I applied a small change nevertheless.  While looking into
this issue I realized that the MXCSR register wasn't preserved
during the call to sigdelayed.  This might or might not influence
the result.  I bet the latter, but better safe than sorry...


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

Attachment: pgpZ65N8ydkWZ.pgp
Description: PGP signature