multitasking/cororoutines

[andrewtholt]

Hi Mitch,

I seem to recall asking you this question a very long time ago, when I was working at Sun, certainly last century.

Did you ever implement a co-operative task system for cforth ?

I see that pause is a deferred word, IIRC it was in openfirmware too.

Thanks

[MitchBradley]

Yes, I have used cooperative MT with an active pause. I don't use it often, but all of my Forth systems are set up so pause can do the right thing.

[andrewtholt]

Hi Mitch, Is there any way I can make use of this ?

…

On Tue, 26 Jan 2021 at 19:12, Mitch Bradley ***@***.***> wrote: Yes, I have used cooperative MT with an active pause. I don't use it often, but all of my Forth systems are set up so pause can do the right thing. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#73 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAYVWSK3LWY73CCF2RIN7XLS34HYVANCNFSM4WTWD4NA> .

[MitchBradley]

I updated the multitasking code for CForth. Pull the latest commit and look at src/lib/test-tasking.fth

[andrewtholt]

Thanks for that. I'll take a look ASAP. Regards, Andrew

…

On Sun, 7 Feb 2021 at 22:37, Mitch Bradley ***@***.***> wrote: I updated the multitasking code for CForth. Pull the latest commit and look at src/lib/test-tasking.fth — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#73 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAYVWSLK62QL3P6RJOIOI2TS54I3TANCNFSM4WTWD4NA> .

[Jos-Ven]

That sounds great.
Unfortunately, I am not able to compile tasking.fth under esp8266-rtos
the words asleep (pause and link are missing.
It would be nice if it is also possible to use tasking.fth with esp8266-rtos!

Kind regards, Jos

[andrewtholt]

A quick scan would suggest that you replace (pause with (pause)

Haven't actually tried it yet, that's from observation.

[Jos-Ven]

Hi Andrew,

Thanks for the quick scan.
Can't replace (pause with (pause) since
(pause) is not defined under esp8266-rtos.

Kind regards, Jos

[MitchBradley]

asleep, (pause, and link are defined in forth.c according to the part of the commit shown below. You will need to recompile to get them.

[MitchBradley]

(pause is the correct name.

[Jos-Ven]

Hi Mitch,
Sorry, that did not work. Here is what I did:
If I clone the main branch then after:
cd /home/pi/cf/cforth/build/esp8266-rtos
bash: cd: /home/pi/cf/cforth/build/esp8266-rtos: No such file or directory

The esp8266-rtos directory seems only to be present in the branch WIP and not in the branch MAIN
After:
git clone https://github.com/MitchBradley/cforth --branch WIP
cd /home/pi/cf/cforth/build/esp8266-rtos
make
make flash

\ Then in cforth I saw:
sifting pause
In vocabulary forth
(40285388) pause
ok see pause
defer pause is
: noop

;
Kind regards, Jos

[Jos-Ven]

Hi Mitch,

After I made the changes manually in forth.c for the words
asleep (pause and link
Then it was possible to compile and run test-tasking.fth
The counter was indeed increased when the background was running.
To be sure multiple tasks could also be handled I added 1 more task.
Here is the code:

\needs multi fl tasking.fth

\ Tests and examples for cooperative multitasking

\ Global variable used by the test tasks
Global counts0
Global counts1
Global counts2

\ Explicit creation of word and task

: do-count0 begin 1 counts0 +! pause again ;
task: count-task0
' do-count0 count-task0 fork
count-task0 wake

: do-count1 begin 2 counts1 +! pause again ;
task: count-task1
' do-count1 count-task1 fork
count-task1 wake

\ Combined creation of task with word to execute
\ background counters3 begin 3 counts0 +! 2 counts1 +! 1 counts2 +! pause again ;

background counters2 begin pause again ;

: .counts ( -- ) ." counts = " counts0 @ .d counts1 @ .d counts2 @ .d cr ;

.counts
pause
.counts
pause
.counts

: run-background ( -- ) begin pause key? until key drop ;

.( Type a key to return to prompt) cr
run-background
.counts
\ end code

Output when counters3 is active:
counts = 0 0 0
counts = 3 4 1
counts = 6 8 2
Type a key to return to prompt
counts = 1332300 1776400 444100

Output when counters2 is active:
ok fl test-tasking.fth
counts = 0 0 0
counts = 0 2 0
counts = 0 4 0
Type a key to return to prompt
counts = 0 656194 0

\ Manual changing:
ok multi
ok pause .counts
counts = 0 656200 0
ok pause .counts
counts = 0 656202 0
ok pause .counts
counts = 0 656204 0

It seems pause does not run all tasks
Here is the link to the changed forth.c:
Jos-Ven@f13c871
I hope the problem can be solved.

Thanks in advance, kind regards, Jos

[Jos-Ven]

Hi, For those who are interested:
I just uploaded some files for pre-emptive multitasking.

See:
https://github.com/Jos-Ven/cforth/tree/WIP/src/app/esp8266-rtos/
Added and changed files: app.fth tasking_rtos.fth extend.c interface.h

and:
https://github.com/Jos-Ven/cforth/tree/WIP/src/app/esp8266-rtos/tests
Added for a test case: pe_tasking.fth

It is all quite experimental.
I could not get it better due to my lack of knowledge of C.
So far only successfully tested on an ESP-12F
Improvements are welcome!

Kind regards Jos