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Re: [RFA] enable software single step on alpha-osf
- From: "Peter.Schauer" <Peter dot Schauer at regent dot e-technik dot tu-muenchen dot de>
- To: kevinb at redhat dot com (Kevin Buettner)
- Cc: drow at mvista dot com, ac131313 at ges dot redhat dot com, brobecker at gnat dot com, gdb-patches at sources dot redhat dot com
- Date: Fri, 16 Aug 2002 23:40:16 MET DST
- Subject: Re: [RFA] enable software single step on alpha-osf
Sigh.
http://sources.redhat.com/ml/gdb-patches/2001-06/msg00383.html
http://sources.redhat.com/ml/gdb-patches/2001-06/msg00512.html
http://sources.redhat.com/ml/gdb-patches/2001-07/msg00001.html
will help figuring out the intent.
> On Aug 16, 3:26pm, Daniel Jacobowitz wrote:
>
> > > Expressions like:
> > >
> > > /* Pass TRUE if our reason for stopping is something other
> > > than hitting a breakpoint. We do this by checking that
> > > 1) stepping is going on and 2) we didn't hit a breakpoint
> > > in a signal handler without an intervening stop in
> > > sigtramp, which is detected by a new stack pointer value
> > > below any usual function calling stack adjustments. */
> > > (currently_stepping (ecs)
> > > && prev_pc != stop_pc - DECR_PC_AFTER_BREAK
> > > && !(step_range_end && INNER_THAN (read_sp (),(step_sp - 16)))));
> >
> > Which reminds me - does that use of INNER_THAN make even the slightest
> > sense on stack-grows-up architectures? I don't think it does.
>
> I don't think so either.
>
> Also, that magical value of 16 just can't be right for all architectures.
>
> But this is one of those areas where we have to be *very* careful.
> We can attempt to make well-meaning changes and then discover many
> months later that we've broken something that used work.
>
> For the above, I think we need to figure out the intent behind the
> condition
>
> INNER_THAN (read_sp (),(step_sp - 16),
>
> and then write an architecture dependent method for it.
>
> Kevin
>
>
--
Peter Schauer pes@regent.e-technik.tu-muenchen.de