[Coco] Asteroids clone, Star Blaster cartridge?

Barry Nelson barry.nelson at amobiledevice.com
Sun Nov 12 16:03:29 EST 2017


> Arthur Flexser
> Sun Nov 12 15:28:28 EST 2017
> 
> In most cases the disk binary is simply the cartridge binary to which a
> small loader has been attached that copies the code back to the original
> $C000 location with the machine in the all-RAM mode and jumps to it.
> (Often, $8000-BFFF is also copied from ROM to RAM in case the cartridge
> uses calls to Color Basic or Extended Basic.)  The exception would be
> copy-protected cartridges that are designed not to work from RAM, where the
> loader might contain some pokes to the code to nullify such provisions.
> Except for such copy-protected cartridges, if should be pretty trivial to
> strip off the loader and save the rest to generate the cartridge dump.
> 
> Art
I agree, in MOST cases. However in this case it appears the code has probably been patched to run at $4000. My attempts thus far to remove any loader and relocate the code back to $C000 and get it to run from there have met with failure, unless I use a loader which copies the binary from ROM at $C000 back to $4000 and runs it from there. This works, BUT it is not how the game was originally intended to run and in any case it would be nice to have a virgin copy.




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