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Re: Faking RWTS13: Trying to figure out how to do something
On Mon, 28 Nov 2005, Don Bruder wrote:
In article
<Pine.LNX.4.62.0511281934110.8203@static-141-149-129-16.buff.east.verizo
n.net>,
Lyrical Nanoha <LyricalNanoha@dosius.net> wrote:
On Mon, 28 Nov 2005, Michael J. Mahon wrote:
Trace it carefully, and you will see that it constructs a return address
on the stack than then RTSs to it.
Eek.
Ah, an apparent newcomer to the joys of stack-diddling :)
I'm not used to anything beyond the "proper" 6502/65C02 stuff - actually
I'm rather new to 6502 ASM in general.
Where do you *THINK* it's going, based on the stack contents when the
rts just above the $CxD1 code executes? (As in "What's the value on the
stack just before the RTS?" - I betcha you find that the high-order byte
is indeed $C6, rather than $86 - The card RTS-es into its own code
unless you diddle the return address after moving it.
It does seem like that, but putting a BRK on the RTS doesn't seem to help
either.
Trace carefully, grasshoppa! :) You're in the ballpark, now you just
have to find your way to the beer stand. :)
LOL
Betcha didn't know you're developing the most effective (not always
fastest, but *ALWAYS* successful eventually) disk-protection cracking
skill known for the Apple II family :) I used to do quite a bit of
cracking in the years-and-years ago - strictly for the ability to do so
- honest - I think only one of my cracks ever left my hand, and that was
an "emergency crack" done on a borrowed disk that fell victim to a 3
year old with a handful of french-fries, necessitating a duplicate copy.
Boot-tracing was something I actually came to enjoy. I've forgotten *SO*
much through disuse, though... <sigh>
Heh. I had to relearn a lot of Apple stuff back in '88 and a little of it
back in '95 after a bit of disuse. Fortunately, the second time I
remembered almost everything, where the first time I forgot almost
everything.
I've got your source code from your earlier posting partially commented
with fairly in-depth info based on what I can remember from my days of
"flyin' the Jolly Roger". If you like, give a holler and when I get
done with it, I'll ship it to you.
Heh. I like to know how the machines work inside. XD
-uso.