Re: Working around -freestanding limitations?

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 2023-04-01 15:26, Hou Van Boere wrote:
> Hi Everyone.
> 
> I know there are several floss RTOS option for us but I don't really
> need all of the supports they offer and they just make things more
> complex.

Certainly using most RTOS from Ada is more complex than using an Ada RTS 
from Ada.

Do you want to use tasking at all? Or just a single thread?


> Here are my goals:
> 
> 1)I want to build my own circuit board with a microprocessor not microcontroller.


Can you explain why? Input/output is often more complex with a 
microprocessor (I assume you mean something that could run a PC or a 
tablet) than with a microcontroller. A microprocessor may need a lot of 
complex initialization and driver SW which you can get in some RTOS but 
not in an Ada RTS. And I believe that circuit-board design is more 
complex for microprocessors than for microcontrollers, however I have no 
experience with either case.


> 2)I want to run with gcc/gnatmake ... -freestanding
> 
> 3)I only need the Ada 83 subset, which I guess is pretty close to Ravenscaler


I see the Ada 83 tasking features as almost orthogonal to Ravenscar. Ada 
83 has no protected objects, and all inter-task communication must be 
done with rendez-vous using task entries. Ravenscar forbids task entries 
and rendez-vous and substitutes protected objects. Both work, but 
Ravenscar is perhaps more resistant to deadlock errors.