[Coco] A way to recompile HDB-DOS with more fixed-address variable space

[Arthur Flexser]

There may be a few programs that are really shoehorned into memory that
will give an 'out of memory' error if you steal 256 bytes from free memory,
though I doubt there'd be very many of them.

Art


On Mon, Feb 3, 2014 at 12:18 AM, Juan Castro <jccyc1965 at gmail.com> wrote:

> But that too is relocated automatically in the DECB init code. Its address
> is in a variable (at $00BA). I compiled a ROM with a 256-byte higher DFLBUF
> and it seems to run. See screenshot:
>
>
> https://lh3.googleusercontent.com/-zUr0rqC3Q-Y/Uu8lg9w0sjI/AAAAAAAAFYM/ivDtf725M9M/s800/GraphicsRelocated.png
>
> Now, I can imagine some software COULD presume the address is "$600 if ECB
> and $E00 if DECB". Which is bad, Bad, BAD. (Does any do?) Hey, even a
> "FILES 10" will relocate the graphics area!
>
> By the way, yes, I'm using the cassette buffer as a variables area for now
> but that will change.
>
>
> On Mon, Feb 3, 2014 at 2:32 AM, Arthur Flexser <flexser at fiu.edu> wrote:
>
> > Long before you hit $2600, you'll run into the PMODE graphics area, which
> > starts at $E00.
> >
> > Art
> >
> >
> > On Sun, Feb 2, 2014 at 10:56 PM, Juan Castro <jccyc1965 at gmail.com>
> wrote:
> >
> > > Redefine the DFLBUF constant, from the current $0989 to, say, $09B9 if
> I
> > > need 48 bytes for my stuff. I realize I can't do that forever or I'll
> > start
> > > messing with the DOS command who needs addess $2600 to load the
> > bootstrap.
> > >
> > > Could I expect some nasty side-effect from some software if I do that?
> > >
> > > (In other news, I'm going to listen to the sage advice recently
> > dispensed,
> > > abandon that "detect signature" scheme and just use conditional
> assembly
> > > for 16K ROMs.)
> > >
> > > Juan
> > >
> > > --
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> > > Coco at maltedmedia.com
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> > >
> >
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