[Coco] The Hobbit ported to 6809 (Dragon64 and coCo2 64k)

[Arthur Flexser]

The new interrupt vectors in the CoCo 3 actually take up only $FEEE-FEFF,
so you don't need to worry about a full 256 bytes, only 18 bytes.

The poke to $FFDE does the same in a CoCo 3 as in the earlier CoCos, but
has the byproduct of removing Super Extended Basic and restoring Basic to
its earlier configuration.  An exception is that $FE00-FEFF remains in the
RAM mode unless you change a particular bit in the GIME as well, and doing
so would probably cause a crash because you'd be switching out these
vectors.

Art

On Sun, Aug 21, 2016 at 4:08 PM, Pere <psergm at gmail.com> wrote:

> Thanks Art,
> POKE&HFFDE,0 implies (on CoCo2) going back to MAP0. Doesn't this apply for
> the CoCo3?
> The Hobbit uses from $E000 till $FEFC so this could be 'THE' problem
> indeed.
> I will try to move $FEE0-$FEFC to another place, despite there is only 256
> free bytes in
> four separate chunks :-(
>
> cheers
> pere
>
> ------------------------------------------------------------
> -----------------------------------------------------------
> Previous message (by thread): [Coco] The Hobbit ported to 6809 (Dragon64
> and coCo2 64k)
> Arthur Flexser flexser at fiu.edu
> Sun Aug 21 14:49:12 EDT 2016
> You can disable Super Extended Basic by simply entering POKE &HFFDE,0 from
> a width 32 screen.  However, the CoCo 3 uses some vectors just above $FEE0
> and the machine will likely crash if these are overwritten;  the above poke
> does not affect this.  It is quite likely that that is what is causing your
> crash.
>
> Disk Extended Basic exists in only 2 versions (not counting third-party
> modifications), and they are versions 1.0 and 1.1, which the CoCo 3
> displays on the startup screen as 2.0 and 2.1.
>
> Art
>
>
>
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