Working around -freestanding limitations?

Working around -freestanding limitations?

[Hou Van Boere]

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.

Here are my goals:

1)I want to build my own circuit board with a microprocessor not microcontroller.

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

What options do I have? I like to keep things small and simple when possible.

Thanks for reading

Re: Working around -freestanding limitations?

[Simon Wright]

Hou Van Boere <houvanboere@gmail.com> writes:

> 2)I want to run with gcc/gnatmake ... -freestanding

-freestanding isn't an option for gnatmake; where does it come from?

> 3)I only need the Ada 83 subset, which I guess is pretty close to Ravenscaler

The Ada 83 subset is going to be larger than Ravenscar.

If you don't want an RTOS you could use one of the light runtimes,
e.g. light-cortex-m0.

Re: Working around -freestanding limitations?

[Hou Van Boere]

" -freestanding isn't an option for gnatmake; where does it come from?"
Ha ha, chatGPT :)

Could you tell me where to find the light runtimes? I have only worked with Ada on full desktops. Does the FSF version ship with light runtimes?

Re: Working around -freestanding limitations?

[DrPi]

Le 01/04/2023 à 18:12, Hou Van Boere a écrit :
> " -freestanding isn't an option for gnatmake; where does it come from?"
> Ha ha, chatGPT :)
> 
I guess it is -ffreestanding : 
https://stackoverflow.com/questions/17692428/what-is-ffreestanding-option-in-gcc

Re: Working around -freestanding limitations?

[Hou Van Boere]

yes thanks -ffreestanding, -freestanding was a typo, sorry

Re: Working around -freestanding limitations?

[Hou Van Boere]

" Could you tell me where to find the light runtimes? I have only worked with Ada on full desktops. Does the FSF version ship with light runtimes?"

I am just answering my own question to avoid wasting people's time. I fount this:
https://github.com/AdaCore/bb-runtimes

Re: Working around -freestanding limitations?

[DrPi]

Le 01/04/2023 à 18:50, Hou Van Boere a écrit :
> " Could you tell me where to find the light runtimes? I have only worked with Ada on full desktops. Does the FSF version ship with light runtimes?"
> 
> I am just answering my own question to avoid wasting people's time. I fount this:
> https://github.com/AdaCore/bb-runtimes
The best way is to use Alire https://alire.ada.dev/

Re: Working around -freestanding limitations?

[Hou Van Boere]

Thanks for the link

Re: Working around -freestanding limitations?

[Niklas Holsti]

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.

Re: Working around -freestanding limitations?

[Hou Van Boere]

Thanks for your feedback Niklas. I am new to Ravenscar(just spelled it wrong today), this is very helpful.

It would be nice to have threads but I am not sure I actually need them.

I have serviced scientific instruments for 24 years now. I want to start fabricating them. I will have some bumps along the way with PCB design but I am confident that it will work out.

I have been playing around with Ada since 2012 but I still have lots to learn and I don't program in the day so it is not my strong suit. The hardware side should work out but I am worried about the software end of things. Ada is lovely but massive. There are so many features, so many libraries(some of which are abandoned). There are only so many hours in a day. 

I have a subset of the language I like and if I can just control CPU  address and data lines, I shouldn't need a RTOS. Trying several of them out could take a great deal of time.

I don't seem to have any extra runtimes with my install:

gnatls -v

GNATLS 11.2.0
Copyright (C) 1997-2021, Free Software Foundation, Inc.

Source Search Path:
   <Current_Directory>
   /usr/lib64/gcc/x86_64-slackware-linux/11.2.0/adainclude


Object Search Path:
   <Current_Directory>
   /usr/lib64/gcc/x86_64-slackware-linux/11.2.0/adalib


Project Search Path:
   <Current_Directory>
   /usr/x86_64-slackware-linux/lib/gnat
   /usr/x86_64-slackware-linux/share/gpr
   /usr/share/gpr
   /usr/lib/gnat

Re: Working around -freestanding limitations?

[DrPi]

Le 01/04/2023 à 18:42, Hou Van Boere a écrit :
> Thanks for your feedback Niklas. I am new to Ravenscar(just spelled it wrong today), this is very helpful.
> 
> It would be nice to have threads but I am not sure I actually need them.
> 
> I have serviced scientific instruments for 24 years now. I want to start fabricating them. I will have some bumps along the way with PCB design but I am confident that it will work out.
> 
> I have been playing around with Ada since 2012 but I still have lots to learn and I don't program in the day so it is not my strong suit. The hardware side should work out but I am worried about the software end of things. Ada is lovely but massive. There are so many features, so many libraries(some of which are abandoned). There are only so many hours in a day.
> 
> I have a subset of the language I like and if I can just control CPU  address and data lines, I shouldn't need a RTOS. Trying several of them out could take a great deal of time.
> 
> I don't seem to have any extra runtimes with my install:

Today, the easiest route is to use ARM based chips as there are 
maintained runtimes for them (through Alire and bbruntimes).

Re: Working around -freestanding limitations?

[DrPi]

>> 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.

Nowadays, microprocessors are rare. Even x86 microprocessors could be 
named microcontrollers since they integrate many (not all) peripherals.

High end microcontrollers are very complex to initialize. Especially 
since they integrate security functionalities (like secure boot), SDRAM 
controllers, PCIe controllers, Gigabit Ethernet controllers, 3D GPUs, 
video encoders/decoders, camera interface, LCD interface, HDMI interface...

Even middle range microcontrollers are (very) complex.

Manufacturers provide drivers source code (in C) for all peripherals. 
They also provide tools to graphically set chip configuration and output 
C code to help the programmer.

Complexity depends on the chip you choose.

Re: Working around -freestanding limitations?

[Hou Van Boere]

Thanks DrPi

I will probably stick with what I know. Most of the instruments I work on have Motorola chips and parallel buses. I don't think i will use SPi, IC2 or dozens of other protocols/features found in most modern circuit boards.

Re: Working around -freestanding limitations?

[DrPi]

Le 01/04/2023 à 18:58, Hou Van Boere a écrit :
> Thanks DrPi
> 
> I will probably stick with what I know. Most of the instruments I work on have Motorola chips and parallel buses. I don't think i will use SPi, IC2 or dozens of other protocols/features found in most modern circuit boards.
Great chips at their time but I'm afraid you'll have hard time compiling 
a dedicated GNAT compiler.

Re: Working around -freestanding limitations?

[Hou Van Boere]

I am sure you are right but still, you get the general idea.

Thermo Electron has pretty much bought most of the industry out. I will copy and paste, mix and match old stuff to re-implement instruments they don't care about anymore. I don't need to make anything cutting edge. The old stuff was more than good enough

Re: Working around -freestanding limitations?

[DrPi]

Le 01/04/2023 à 19:24, Hou Van Boere a écrit :
> I am sure you are right but still, you get the general idea.
> 
> Thermo Electron has pretty much bought most of the industry out. I will copy and paste, mix and match old stuff to re-implement instruments they don't care about anymore. I don't need to make anything cutting edge. The old stuff was more than good enough

Indeed, an interesting project.

You first need a Ada cross-compiler. Here is a link about this : 
https://wiki.osdev.org/GNAT_Cross-Compiler

You also need a runtime. This is up to you to code it. You can use 
bbruntimes as a template. This can request modifications on your 
hardware. For example, the runtime needs a timer to track time. If your 
microprocessor do not have an embedded timer, you'll have to add one on 
your board.

Other links of interest :
https://forum.ada-lang.io/
https://github.com/ohenley/awesome-ada

Matrix rooms (https://matrix.org/clients) :
Ada news : https://matrix.to/#/#ada-lang:matrix.org
Ada language : https://matrix.to/#/#ada-lang:matrix.org
Alire : https://matrix.to/#/#ada-lang_Alire:gitter.im

Many other resources exist.

Re: Working around -freestanding limitations?

[Hou Van Boere]

Thanks for the fantastic help today DrPi

Re: Working around -freestanding limitations?

[DrPi]

Le 01/04/2023 à 20:57, Hou Van Boere a écrit :
> Thanks for the fantastic help today DrPi
You're welcome :)

Re: Working around -freestanding limitations?

[Hou Van Boere]

Thanks Phil! Huge help