Subject: Re: Powerpc signal handler with floating point registers
To: None <port-powerpc@NetBSD.org>
From: Matt Thomas <matt@3am-software.com>
List: port-powerpc
Date: 03/01/2005 10:25:49
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.


-- 
Matt Thomas                     email: matt@3am-software.com
3am Software Foundry              www: http://3am-software.com/bio/matt/
Cupertino, CA              disclaimer: I avow all knowledge of this message.