please dont rip this site

PIC 18C Microcontoller Program Flow Method

Co-routines/cooperative tasks mainline cocalls only

Bob Ammerman [rammerman at prodigy.net] of RAm Systems says

The PIC18Cxx2 chips contain quite a few nice new features. One of the neatest is programmable access to the stack. This feature allows many powerful tricks.

Notes:

  1. this code has _NOT_ been tested!
  2. all multi-byte values are little-endian
  3. I assume the code space never exceeds 16 bits worth (which it never will on the 242, 252, 442 or 452 chips).
Co-routines/cooperative tasks version 1

Note: assumes that all cocalls are from mainline code (ie: the subroutine
stack is empty)

 CBLOCK
   TASKX_PC:2 ; Address of next instruction to run in task X
   TASKY_PC:2 ; Address of next instruction to run in task Y
 ENDC

initialize:
  ; initialize values for all but the first task
   movlw low(tasky)
   movwf TASKY_PC,A
   movlw high(tasky)
   movwf TASKY_PC+1,A

   ...fall thru into first task...
taskx:
   .
   .
   rcall x_cocall_y
   .
   .
   rcall x_cocall_y
   .
   bra  taskx

x_cocall_y:
   movff TOSL,TASKX_PC
   movff TOSH,TASKX_PC+1
   movf     TASKY_PC,W,A
   movwf  TOSL
   movf     TASKY_PC+1,W,A
   movwf   TOSH
   return

tasky:
   .
   .
   rcall y_cocall_x
   .
   .
   rcall y_cocall_x
   .
   bra  tasky

y_cocall_x:
   movff TOSL,TASKY_PC
   movff TOSH,TASKY_PC+1
   movf    TASKX_PC,W,A
   movwf TOSL
   movf    TASKX_PC+1,W,A
   movwf TOSH
   return


file: /Techref/microchip/18c/multitask-coop1-ba.htm, 1KB, , updated: 2000/10/12 12:14, local time: 2024/3/18 22:38,
TOP NEW HELP FIND: 
34.237.245.80:LOG IN

 ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF="http://piclist.com/techref/microchip/18c/multitask-coop1-ba.htm"> PIC 18C Microcontoller Program Flow Method for Co-routines/cooperative tasks mainline cocalls only</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?

  PICList 2024 contributors:
o List host: MIT, Site host massmind.org, Top posters @none found
- Page Editors: James Newton, David Cary, and YOU!
* Roman Black of Black Robotics donates from sales of Linistep stepper controller kits.
* Ashley Roll of Digital Nemesis donates from sales of RCL-1 RS232 to TTL converters.
* Monthly Subscribers: Gregg Rew. on-going support is MOST appreciated!
* Contributors: Richard Seriani, Sr.
 

Welcome to piclist.com!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .