[Coco] Cartridge memory - mapping in and out

[Phill Harvey-Smith]

Quoting Arthur Flexser <flexser at fiu.edu>:

> P.S.  I should have elaborated that a bit more....Super Extended   
> Basic is very cleverly patched into the CoCo 1/2 Basic in such a way  
> as to allow going to ROM mode without anything weird happening.  All  
> the hooks into the Super Extended code have "underneath" them, in  
> ROM, the standard, un-Super vectors,  so all that happens when you  
> switch out Super Extended Basic by going to ROM mode is that you  
> revert to the CoCo 1/2 version of Basic, pretty much.  Same thing if  
> you copy ROM to RAM.  If you try to reference a Super Ext. Basic  
> command, you just get a syntax error, not a crash, same as if you  
> tried that on a CoCo 1/2.

Humm this has got me thinking so what where the extra facilities  
offered by SECB ?
where these all commands and functions designed to handle the new  
graphics moades and other hardware of the CoCo3 or is there stuff in  
there that would be of use
to a CoCo 1/2 etc.

The reason I ask is that it should be possible to backport SECB to any  
CoCo running in all RAM mode, asuming that there is something usefull  
to backport :)

Also when accessing DOS I presume that it would switch to using the  
DOS ROM on the DOS cart for that or did the extra SECB code reside in  
the $E000-$FEFF area where it would not normally interfere with a copy  
of the DOS rom in the $C000-$DFFF area ?

Cheers.

Phill.



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