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 Robotics / RCX / pbFORTH / 312
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Subject: 
RE: How much RAM is left?
Newsgroups: 
lugnet.robotics.rcx.pbforth
Date: 
Fri, 5 May 2000 12:34:56 GMT
Viewed: 
1588 times
  
The little brick has LOTS of room left for cool apps.....

Speaking of which how does one tell how much RAM is available?
Is there more than one memory pool, i.e. one for ALLOT and another
for dictionaries?

Nope, the memory is allocated linearly from the end of the image.
The current image size is 12 or 13K. New dictionary entries and ALLOTed
memory are interspersed as they occur.

NOTE WELL that there is a subtle bug in the RCX ROM routines when
they allocate local stack space. They were written with the
assumption that the processor stack was a 256 byte block of memory.

When I was debugging early versions of pbForth, if the stack spanned
a 256 byte boundary when SENSOR_READ was called, the result was
chaos. This is important to keep in mind when using multitasking.

The task stack is ALLOTed as needed, so be VERY sure it won't span
a 256 byte boundary. I wish I could fix this, but right now I can't.

I'm beginning to think that some of my communication problems might
be hardware.

....on you Linux machine, right? What version of Tcl/Tk are you
running? My beta stuff is pretty much 8.0.5 compatible except for
a [string repeat] operation that needs 8.3, it's easy to change
if I have to.

I can also point you at a ready built RPM of 8.3.1

Cheers,

Ralph Hempel - P.Eng

--------------------------------------------------------
Check out pbFORTH for LEGO Mindstorms at:
<http://www.hempeldesigngroup.com/lego/pbFORTH>
--------------------------------------------------------
Reply to:      rhempel at bmts dot com
--------------------------------------------------------



Message is in Reply To:
  How much RAM is left?
 
(...) I believe that. 32k of RAM is a luxury for forth. That's another thing people don't generally understand about forth, they way it effectively compresses runtime software. I've heard of ram reductions of a factor of 5-10 for forth when compared (...) (25 years ago, 5-May-00, to lugnet.robotics.rcx.pbforth)

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