I don't know if I'm weird or if it's just normal to get random reverse engineering urges.
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@foone Try 86box?
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@jernej__s didn't have it installed. guess I'll go try it now
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Foone🏳️⚧️replied to Foone🏳️⚧️ last edited by [email protected]
I have now tested 86box.
the unpacker crashes in exactly the same way -
went and found to other copies from other places, they both crash in the same way. weird.
Here's the link if anyone wants to take a crack at running it:
http://cd.textfiles.com/smmodem/ARCHIVE/SBUST24R.ZIP -
the program seems to do some kind of self-modifying code and then it ends up overwriting actual code with gibberish which obviously doesn't work
and we end up in an infinite loop of invalid instructions -
correction: the memory gets repeatedly overwritten before it ends up in the endless invalid-instruction loop.
I think it's trying to do some kind of unpackery nonsense but it breaks for god only knows what reason and it ends up uncompressing over itself
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wait this is shareware. did they timebomb this?
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no, unless they're getting tricksy with it.
Like, timebombed software sometimes doesn't just check the date: it checks if you're cheating at the date.
One easy way to do this is to look at what files you have on your drive. if there's a bunch from 2010, you are probably lying about it being 1994
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@foone technically my first game was "Dracula" for the C64 (although i only got to play it once since i didn't have a C64), but my real first game was Keen IV (shareware from the grocery store) for my Leading Edge 486.
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Foone🏳️⚧️replied to Cameron 💙🏳️⚧️🦌 last edited by [email protected]
@old_angry_queer Keen 4 was my third game! It would have been the second, but I couldn't get it working. I had to wait a couple months for my grandma to visit and use her DOS SKILLZ to figure it out for me
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dude! I was just reading the Echelon manual and you can send off to Access software, for 5$ (plus 0.50$ shipping and handling) they'll send you a COMPLETE patrol zone map, with all areas filled in!
It's only been 37 years or whatever, you think that offer is still good?
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Access Software hasn't existed since 1999. Microsoft bought them. Maybe Microsoft has that somewhere in their archives...
HEY MICROSOFT, OPEN SOURCE ECHELON!
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that rarely works. but it's worth trying.
ANYWAY I looked through all the echelon copies on eBay, none have the filled-out map (or if they do, the owner doesn't know, because they're still sealed)
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huh. in this code, it uses the pre-assigned AX register when MS-DOS calls the entry point.
I... don't know what's in AX at the start of a DOS program? I'm sure that's documented somewhere, but I'm not sure where
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this at least says what it'll be: it's 0000, in nearly all cases
https://www.fysnet.net/yourhelp.htm -
I wonder if DOSBox sets it differently
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Nah. Whatever is going wrong is elsewhere.
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I tried using UNP again: it throw a memory error from AXE.
and I was able to confirm (since I have AXE2.2, the packer used) creates a file that breaks in the same way in UNP.
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I missed that there was a -l option to UNP for bigger memory blocks, which makes it "succeed" at decompressing.
I say "succeed" because running the resulting EXE causes an immediate crash to IBM ROM BASIC NOT AVAILABLE -
I tried doing the same on an IBM XT with actual ROM BASIC but sadly it just hung
