BBC BASIC for Windows
Programming >> Assembly Language Programming >> SYS"CreateThread"
http://bb4w.conforums.com/index.cgi?board=assembler&action=display&num=1492453887
SYS"CreateThread"
Post by Ric on Apr 17th, 2017, 6:31pm

I have posed this question on the other forum, but it cant harm to ask here too,

Probably one for Richard, but does anyone know if it is possible to get 2 assembly routines to run truly in parallel? With maybe a shared memory location to trigger the routines. Say:


Routine 1
Do something
On result set !data=1
Repeat routine 1


Routine 2
Check !data
If 0 repeat routine 2
If 1 do something
Set !data=0
Repeat routine 2

Richard pointed me at winlib2 and winlib4 but if I'm honest I do not understand the coding in these demos. there are way to many SYYSTEM/API calls to take in and I don't know which ones are relevant to CreateThread.

I need something with far less variables for my tiny brain to get round or even better could someone supply just the basic code.

This is a simple pseudo code of what I would like to produce :-

SYS "CreateThread" assembly label1
SYS "CreateThread" assembly label2
SYS "CreateThread" assembly label3

etc...

From my BB4W program, leave the assembly running in the background with a few memory location changes to operate the assembly routines and then for them to terminate only when the BASIC program is terminated.

Regards Ric







Re: SYS"CreateThread"
Post by Ric on Apr 19th, 2017, 2:26pm

Found a wonderful post by Michael Hutton which has answered all my questions and more, (Thanks Michael).

This is the result, it is not very well put together and doesn't error trap too well but have a go and see the speed difference between Series ASM and Threaded ASM. It really opens up the possibilities for graphics generation.

https://1drv.ms/u/s!AqibHqCkE1VQkGSysm8B0c6voOI9
Regards Ric
Re: SYS"CreateThread"
Post by DDRM on Apr 20th, 2017, 08:14am

Hi Ric,

Thanks for posting some working code - I get almost a halving of the time, which is perhaps a bit disappointing on a quad-core machine where you have tried to grab 3 threads, but I suspect there's all sorts of junk using some of my cores...

BTW, your link misses the initial "htt", so it doesn't work when clicked - if you could amend it, that would be helpful! Or here it is...

https://1drv.ms/u/s!AqibHqCkE1VQkGSysm8B0c6voOI9

Best wishes,

D
Re: SYS"CreateThread"
Post by Ric on Apr 20th, 2017, 08:35am

Thanks D

I get the same results on my laptop, I have tried to change the number of frames rastered so the delay for setting up the thread is minimized, but still get the same result. I can only presume 2 threads is not twice as quick as 1.

PS changed link,

Regards Ric
Re: SYS"CreateThread"
Post by Ric on Apr 29th, 2017, 8:51pm

Could someone with a slightly more powerful machine try this code and post the results back.

The code is threading in ASM, again it is not pretty with little error trapping, but it works smiley

https://1drv.ms/u/s!AqibHqCkE1VQkHgjdT7XQF5DYExJ

Good luck

Ric
Re: SYS"CreateThread"
Post by DDRM on May 2nd, 2017, 08:09am

Hi Ric,

222 vs 478, on a quad core i5-based machine, if that helps.

Best wishes,

D
Re: SYS"CreateThread"
Post by Ric on May 2nd, 2017, 2:14pm

Cheers D

Not sure yet, but is slightly quicker than mine.

Ric