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| From: indi (all posts)
Date: 1998-05-17
Subject: Re: Tapes!
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>There was one turbo loader (maybe by Anirog) that was very difficult, and
>I gave up. Part of the loader code will be in the tape buffer, and the
>rest will be loaded to $2xx, so that it will overwrite the beginning of
>the tape buffer. The program will autostart, and the program starts with
>a loop that uses the undocumented DEC+CMP instruction to decrypt the rest
>of the program. It depends on the CPU register values set by the ROM
>routines. If I had had more time and a blank tape, I would have written a
>program that is equally big and ends in the same bytes, but stores the CPU
>registers when started.
I've found a few of these... fortunately since its loading under emulation, I don't have to worry about it... This is what makes it so hard to "convert" using an external program.
Mike
^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^
Mike Dailly mike@scotch.demon.co.uk http://www.scotch.demon.co.uk
(Please remove the <REMOVE_ME> from my e-mail address when replying)
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