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Six
Registered: Apr 2002
Posts: 287 |
DTL Jetpack BASIC
This was never properly cracked. There's a copy @ http://www.haddewig.de/nogames64/tools.html but it still has dongle protection and won't run. There's a non-protected program on the disk ("ERROR LOCATE"), but the main compiler still needs the dongle to run. There are also no docs.
Why is this one so important to preserve? Because literally LEGIONS of c64 games were written with it.
I had a go at trying to break the protection, and I'm sure I eventually could - but it's a bear.
At the end of each file (and the compiler is compiled with itself, btw) there is a byte sequence. TWO of those bytes indicate whether or not the program is dongle-protected. BUT, fixing a protected DTL-BASIC program is not as simple as changing those bytes. It uses them to calculate a bunch of other values, in multiple places in the runtime library.
The (tape-port) dongle check is also obfuscated, but easy enough to find.
So, this is going to take some serious skill to bust - but once its busted, it opens the door for reversal tools that can be used to resource games like Roadwar 2000.
Any takers? Can I persuade anyone to at least have a look at it? |
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
PET manual added.
Decompiler is for internal use only for a moment. I have fixed a bunch of bugs since July when the above source was generated, but there are still couple of things which need fixing. BASIC extensions and overlays are the latest thing corrected, but there's still work to be done I'm sure. |
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
Yes, I wrote the decompiler after I did complete disassembly of the runtime library. I get the raw P-code and decompiled basic. Basic code is then fed through another program to do some post-processing like changing "line numbers" to decimal. |
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Moloch
Registered: Jan 2002
Posts: 2896 |
Thanks for posting all of this! Like Six, I've been searching for this manual for a long time. My bad luck, I routinely missed DTL packages on eBay in the last few years. |
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Zer0-X
Registered: Aug 2008
Posts: 78 |
I guess no one has a spare dongle to sell?
Could reverse what's it made of, but as it's likely potted in epoxy it would be somewhat "destructive" process. |
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Six
Registered: Apr 2002
Posts: 287 |
I have a dongle. I guess I could sacrifice it for deconstruction if someone was going to document how it worked in such a way that I'd be able to build a new one. |
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
It would be interesting to see if you get the same key from dongle as I did - 24 02. Just run dongle2.prg with the dongle connected and check the first two hex numbers. My dongle reported 00 after first 16 bits.
I would just use two 74165 chained together for the dongle, Zer0-X wants to know what exactly was used :) |
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Six
Registered: Apr 2002
Posts: 287 |
I should be able to test this this weekend. The printed numbers on all of them are the same, at least. I'm assuming the side that says "DTL BASIC" is up? |
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Six
Registered: Apr 2002
Posts: 287 |
Just ran the test. 2402 and then all 0000 from there.
So those match the target bytes in the protected original compiler. Did you crack this yourself?
If so, could you give us a rundown of how it was protected, for history's sake? |
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Count Zero
Registered: Jan 2003
Posts: 1825 |
Six mentions "LEGIONS of c64 games" compiled with this. During my active time I didn't really come across anything "mastered" using this compiler AFAIR.
Is there a list? Is DTL somewhere near RTL64 which I think was used for e.g. Silent Service? Or do I mix something up here?
Did anybody document a little more regarding c64 compilers? On my local collection there of course are several Blitz/Austro versions, Basic Boss is somewhat "new age" and also Laser Genius sounds interesting next to petspeed or simon's compiler. Next to speed, origin/clone, also the availability of a decompiler would be of interest. Is there such a comparison or did I just miss something on my websearch? |
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Six
Registered: Apr 2002
Posts: 287 |
I've seen that RTL-64 file on many a floppy over the years. The big three that always come to mind when this discussion arises are Roadwar 2000, F-15 Strike Eagle, and Silent Service. It was used on a number of SSI titles, I'd have to review them to make a solid list.
At one point I did a filename search across all of my floppy image collection and came up with something like 800 instances of the RTL-64 file. |
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