Re: [D64] Seven Cities of Gold map disk hacking

From: Nate Lawson <nate_at_root.org>
Date: Tue, 15 Jul 2014 21:24:33 -0700
Message-Id: <F9BD1F8A-25F6-4E19-B151-077724C0395A@root.org>
On Jul 15, 2014, at 6:51 PM, Rob Eaglestone <robert.eaglestone@gmail.com> wrote:

> For a long time I've been thinking about hacking the map disk format for the Seven Cities of Gold.  And then making tools to view, modify, and architect  maps, that sort of thing.

Easiest is to dump RAM while you're somewhere on the map, then seek through all data from the D64 to look for a sliding window of 10 bytes or so that matches RAM contents. Mark where this window begins and ends on the disk. Then move to another place on the map and repeat. The same place you always hit will be the code in RAM. The addresses that change locations on disk will be the data.

Soon you’ll know what disk locations correspond to every place you walked to.

The best general way to tackle something like this is software fuzzing. You run your test in a tight loop and randomly (or sequentially) poke in values until you have some difference in behavior, resetting back to a clean slate each iteration. By comparing where/what causes a change in behavior, you’ll understand the code.

-Nate


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Received on 2014-07-16 05:00:02

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