[RFC/i386newframe] Restore all registers from sigframe

[Andrew Cagney]

>    Date: Thu, 29 May 2003 15:03:11 +0200
>    From: Michal Ludvig <mludvig@suse.cz>
> 
>    Hi,
> 
>    the attachd patch enables restoration of all registers when unwinding 
>    from a signal handler. Currenty only PC and SP were restored and it's a 
>    loss since all GPRs are there on the stack.
>    It's even more important for AMD64 because there parameters are usually 
>    passed in regs and not on the stack.
> 
> Indeed.  We defenitely need %ebp too to reliably unwind on the i386.
> Might just as well go all the way.  The other registers are usefull
> for local variables stored in registers too.  Floating-point registers
> are a bit tricky though.  It's fine to leave them out for now though.

Ya!  At least two people now get it!  A frame should unwind anything.

Andrew