[Coco] Asteroids clone, Star Blaster cartridge?

[Darren A]

On Sun, Nov 12, 2017 at 1:28 PM, Arthur Flexser wrote:

> 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.
>


This particular game was not written using position-independent code.  It
has either been re-assembled or extensively patched such that all absolute
address operands from C000-DFFF have been changed to 4000-5FFF.

To make a cartridge version, a loader could be added to the image which
copies the code from ROM down to RAM at $4000 and executes it from there.


- Darren