Subject: Re: Powerpc signal handler with floating point registers
To: Matt Thomas <matt@3am-software.com>
From: Nathan J. Williams <nathanw@wasabisystems.com>
List: port-powerpc
Date: 03/01/2005 13:40:15
Matt Thomas <matt@3am-software.com> writes:

> At 04:37 PM 2/28/2005, Nathan J. Williams wrote:
> >Matt Thomas <matt@3am-software.com> writes:
> >
> > > At 06:02 PM 2/25/2005, you wrote:
> > > >Just tried -current (NetBSD 2.99.16). Still doesn't
> > > >seem to work.
> > >
> > > You need use sigaction and specify SA_SIGINFO.
> > > Only in that case will FP (or AltiVec) registers be preserved.
> >
> >What's the justification for this restriction? I'm not aware of any
> >language in SUSv3 or the PPC ABI that restricts FP code in signal
> >handlers.
> 
> Because that's the way it's been done.  I didn't design it but I can
> understand the reason for it.  Note that sigcontext doesn't have
> space for the FP register set.

So if we can't fix it, where do we document this brokenness?

        - Nathan