Re: STM32F4 GNAT Run Time System - roadmap

["Randy Brukardt" <randy@rrsoftware.com>]

"Simon Wright" <simon@pushface.org> wrote in message 
news:lya8pnh1dq.fsf@pushface.org...
> ...I've not done any evaluation yet
> aside from noting that they generate the GNAT-specific
> Volatile_Full_Access aspect, which is noted in the 'under development'
> version of the GCC docs (so, will likely be in GCC 6). Maybe plain
> Volatile will do (but users would have to remember to access the whole
> register explicitly, rather than leaving it up to the compiler to Do The
> Right Thing); that would be an easy-enough patch.

The ARG has decided on a different direction to fix the problem addressed by 
Volatile_Full_Access; essentially, accesses to non-volatile components of 
atomic objects have to be accessed with a read-modify-write cycle. (See 
AI12-0128-1.) Various parts of Annex C will be rewritten to make that make 
sense.

I think someone here originally proposed that (or at least something like 
it); it took us quite a while to come around to that view, mainly because of 
compatibility concerns. But there is also the concern of doing something 
unexpected.

Anyway, I don't expect that there is much use of that GNAT-specific aspect 
once the changes are approved (probably will happen next year at our next 
meeting).

                                                     Randy.