Re: [Arm] Stack pointer setup thumb

[Alexander Fedotov <alfedotov at gmail dot com>]

On Thu, 7 Mar 2019 at 18:45, Nick Clifton <nickc@redhat.com> wrote:

> Hi Alex,
>
> > I hope you are have some memories on this fix :)
> >
> https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=commit;h=026f9d290f5fe85fe9bd3a56be378fc794e28473
>
> Not really :-(
>
> > Is this still relevant ?
>
> The whole patch, or just part of it ?


That part below (with sp initialization)

>
>
> > The problem is that users complaining that it has different behavior
> > in ARM and Thumb modes for one Cortex-R core. And they do expected
> > that library will make some minimal initialization in both ISA
> > versions.
>
> Well to be honest I really do not remember what prompted this patch in
> the first place.  So if you have a fix which makes the users happy and
> which does not break anything then I would say "go for it". :-)
>
> > Should we just remove this ?
> > +#ifdef __thumb2__
> > +       /* XXX Fill in stack assignments for interrupt modes.  */
> > +#else
>
> Sure - I would have no problems with that.  The comment was more
> of a suggestion that someone needs to make sure that the stack
> pointer is set up before interrupts happen, but it does not have
> to be in this particular piece of code.  Plus presumably this has
> already been done, or else many more people would be complaining
> about interrupts not working in Thumb mode.
>

Yep. Basic idea is to have sp initialization for exceptions as well.
Actually I already proposed a patch for this piece of code where I moved
initialuzation in weak subroutine. But I saved this ifdef there as well. I
will update patch then :)

>
> Cheers
>   Nick
>

Thsnk you Nick !
-- 
Best regards,
AF