[Coco] Suggested RAM area for ML program to be used from BASIC?

[jdaggett at gate.net]

Art

>From $FA0C to $FDFF, about 1012 bytes. A rather small machine language 
program could fit there. The author's picture is loaded at $0E00 and is 
allocated $1800 (6144)bytes. Unless RSBASIC over writes this block is 
uncertain. It would seem to be a waste of space to me. 

james

On 8 Jun 2008 at 1:34, Arthur Flexser wrote:

> There's some space available above the end of Super Extended Basic
> that you could use for the CoCo 3 version (which would also work for
> the CoCo 1/2 if you copied ROM to RAM first ONLY for the earlier
> machines--don't do that for the CoCo 3 or you'll knock out Super
> Extended Basic).  I don't have my reference materials handy, but if
> your program was at $FC00 or thereabouts, that'd probably be high
> enough to clear the top of Super Ext. Basic.  Perhaps someone here
> could chime in with a more precise answer.  There's a character set
> used by HPRINT up there somewhere, then above that is garbage you can
> safely overwrite.
> 
> A small correction to my earlier statement about CLEAR:  if your
> program is at $7F00, you probably need to use CLEAR 200,&H7EFF--the
> extra byte, I believe, is needed only for the CoCo 3.
> 
> Art
> 
> On Sun, 8 Jun 2008, Fedor Steeman wrote:
> 
> > Thank you guys and especially Gene for the fascinating story. I was
> > already getting a feeling that all useful memory would be used up in
> > a CoCo3.
> > 
> > I am not sure yet how big it would become and I need to preserve all
> > of BASIC, so using the cassette buffer, although an interesting
> > suggestion, wouldn't be it.
> > 
> > I think I will proceed with the CLEAR statement.
> > 
> > However, I wonder, if (still) only 32K would be available in Super
> > Extended Color Basic, what is all the memory at the bottom of RAM,
> > supposedly 'Unused by Basic' used for (0-5FFFF)? Maybe I can have a
> > CoCo1/2 version reside at E000-FEFF and a special CoCo3 version
> > somewhere else?
> > 
> > Cheers,
> > Fedor
> > 
> > 2008/6/8 Arthur Flexser <flexser at fiu.edu>:
> > 
> > > On Sat, 7 Jun 2008, Frank Pittel wrote:
> > >
> > > > I don't remember where I got this from but I seem to remember a
> > > > way to reserve memory for machine language programs from within
> > > > a basic program. Seems like the best way to do it to me.
> > > >
> > > > Frank
> > >
> > > You're thinking of the CLEAR statement:  if the ML program is at
> > > $7F00, do a CLEAR 200,&H7F00 to protect the program from Basic and
> > > reserve the usual 200 bytes of string space just below it.  This
> > > would generally be in the first line of any Basic program that has
> > > to coexist with the ML.
> > >
> > > Art
> > >
> > >
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