[Coco] MESS CoCo Emulation
Robert Gault
robert.gault at att.net
Tue Jan 15 09:30:12 EST 2013
Arthur Flexser wrote:
> Some cartridge games were protected from running from a RAM copy
> transferred to the cartridge ROM area. Does MESS simulate running the
> cartridge from ROM, not from a RAM copy? Canyon Climber, if I'm
> remembering right, was written by Steve Bjork, who in his later
> cartridge games put heavy protection to keep them from running from
> RAM. (Or does "verified cartridge image in CCC format" mean the
> protection has already been removed?)
>
> Art
>
Very good point Art. MESS does simulate ROMs to the extent that you can't change
memory in the ROM area. That was the normal method for checking for a copy, POKE
ROM memory and if it changes crash the program.
I've found two different .ccc copies of Canyon Climber. One works with MESS
while the other doesn't. For the one that works, it will not work with coco
emulation but does with cocoe emulation.
This could be a fluke in MESS or the program may be using ROM code from $8000-$9FFF.
Robert
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