[Arm] Stack pointer setup thumb

Nick Clifton nickc@redhat.com
Thu Mar 7 15:46:00 GMT 2019

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 ?

> 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.


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