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Subject: 
Re: Maximum Subroutine numbers?
Newsgroups: 
lugnet.robotics.rcx.robolab
Date: 
Sun, 28 Dec 2003 16:52:00 GMT
Viewed: 
10140 times
  
I don't use Robolab, but I can offer some insight into how the RCX firwmare
operates with subroutines (and events) that may partially explain your
problems.

RCX firmware supports 8 (eight) subroutines per slot. Internally they are
numbers 0 to 7.

FIrmware does not support nesting of subroutine call. There is no firmware
error detection. Firmware appears to keep only a single return address
(rather than a stack) for subroutine returns. A nested subroutine call
sequence will "wipe out" the original return address.

I suspect that events and subroutines don't mix well and may very well have
software bugs. They both interrupt the sequential instruction address
sequence. I wouldn't be surprized that a subroutine 'return' instruction may
cancel any existing event 'monitoring' sequence. [I have not tested this].

Hopefully above may help in understanding the problems with events and
subroutines in some recent posts.



Message has 2 Replies:
  Re: Maximum Subroutine numbers?
 
While I was dwelling on the fundamental interconnectedness of all things on Sun, 28 Dec 2003 16:52:00 GMT, "Dick Swan" <dickswan@sbcglobal.net> wrote: <snip> (...) It doesn't happen most of the time, so the conflict would have to have more (...) (21 years ago, 28-Dec-03, to lugnet.robotics.rcx.robolab)
  Re: Maximum Subroutine numbers?
 
(...) Mmhhh... interesting! that could explain why I had some NQC programs using events that worked fine and some others that didn't... Experiments needed! Thanks Dick, Philo (21 years ago, 29-Dec-03, to lugnet.robotics.rcx.robolab)

Message is in Reply To:
  Re: Maximum Subroutine numbers?
 
Following up my own post with more information: I found in the Minnesota FIRST League's Software Training Manual the statement: "Local subroutines are identified and called by number (1-8)." This suggests that unlike containers and most other (...) (21 years ago, 28-Dec-03, to lugnet.robotics.rcx.robolab)

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