Re: [distortos-development] Newbie getting started

[Kamil S. <dis...@di...>]

On Sat, 2018-02-03 at 11:46 -0500, Trampas Stern wrote:
> I am new to RTOS and distortos, does someone have some good
> documentation on how distortos works and how to get started?

Hello Trampas!

You can find some documentation on project's website
http://distortos.org/

Of special interest are following articles:
http://distortos.org/documentation/arm-toolchain-windows/
http://distortos.org/documentation/creating-configuring-project-eclipse/

There's also API reference generated with doxygen
http://distortos.org/api-reference/

Some info can also be obtained from the changelog in the repository
https://github.com/DISTORTEC/distortos/blob/master/CHANGELOG.md

Generally I'm afraid that documentation and guides are not very good at
this moment... However if you need some guidance or if you have
specific questions I will be more than happy to help you and answer
your questions.

As to "how distortos works" - it basically works in the same way as any
other RTOS. When a context switch is required it is performed in
interrrupt (PendSV in case of ARMv6-M and ARMv7-M) - registers of first
thread are "pushed" on its stack (1), then its stack pointer is saved
in its thread control block (2), next thread control block is marked as
active (3), its stack pointer register is restored (4), then the
registers of this thread are "popped" from stack (5). This is one of
very few pieces of code in distortos which is (partially) written in
assembly language, thus not very friendly for a beginner.

(1) - https://github.com/DISTORTEC/distortos/blob/7d58c175f4fd4e2150033fbddf662f69ff1dd910/source/architecture/ARM/ARMv6-M-ARMv7-M/ARMv6-M-ARMv7-M-PendSV_Handler.cpp#L149

(2) - https://github.com/DISTORTEC/distortos/blob/7d58c175f4fd4e2150033fbddf662f69ff1dd910/source/scheduler/Scheduler.cpp#L254

(3) - https://github.com/DISTORTEC/distortos/blob/7d58c175f4fd4e2150033fbddf662f69ff1dd910/source/scheduler/Scheduler.cpp#L255

(4) - https://github.com/DISTORTEC/distortos/blob/7d58c175f4fd4e2150033fbddf662f69ff1dd910/source/scheduler/Scheduler.cpp#L257

(5) - https://github.com/DISTORTEC/distortos/blob/7d58c175f4fd4e2150033fbddf662f69ff1dd910/source/architecture/ARM/ARMv6-M-ARMv7-M/ARMv6-M-ARMv7-M-PendSV_Handler.cpp#L162

Regards,
Kamil Szczygiel