Jetboy patch

Flyingmouse · Post by **Flyingmouse** » Fri Sep 03, 2010 3:28 am

I need Generic Mod 2's jetpack patch for Keen 3... has this already been posted?

levellass · Post by **levellass** » Sat Sep 04, 2010 9:42 am

This is the standard patch, it's not quite as good though.

#Pogo jetpacks 
%patch $7627 $90

Flyingmouse · Post by **Flyingmouse** » Sun Sep 05, 2010 7:14 pm

I don't get something...
What does this actually edit? A3 is the normal pogo code, but all other values I've tried have the same effect as 90.

lemm · Post by **lemm** » Mon Sep 06, 2010 1:23 am

A3 starts a mov instruction. The instruction following the mov instruction is CALL to the gravity procedure.

The next byte after $A3 is $38, so patching with $90 effecitvely converts the mov into a CMP instruction. The new cmp instruction overlaps with the existing call, cancelling the call to gravity.

A better patch would be $762A $90 $90 $90.

Flyingmouse · Post by **Flyingmouse** » Mon Sep 06, 2010 2:48 am

Thanks!

Come to think about it, I wonder what else could be done with the pogo...

EDIT:
In http://www.keenmodding.org/viewtopic.php?t=1272, what disassembler is used in lemm's post? That looks more readable than what I get from using Recstudio.

lemm · Post by **lemm** » Mon Sep 06, 2010 4:22 am

IDA

There's a free version there, as well as a pro version.

I also have a comprehensive ida disassembly file for keen1 and partials for other vorticons episodes if you want them (but I believe they'll only work for pro version).

levellass · Post by **levellass** » Fri Sep 10, 2010 11:43 am

Oh so only people who love Ida can get the disassembly huh?

Thanks for updating the patch Lemm, LL's patches tend to be rather random.

lemm · Post by **lemm** » Fri Sep 10, 2010 7:50 pm

A text file of the disassembly can be produced if anyone wants it, but I find it more convenient to browse using IDA.

levellass · Post by **levellass** » Sun Sep 12, 2010 4:17 am

I should think that would be very likely, many people out there just don't have your flair for these things. Me for instance.

lemm · Post by **lemm** » Wed Sep 15, 2010 7:25 am

If you want it, the disassembly (k1disasm.tar.bz2) is in the PCKF IRC Dropbox in my folder.

Flyingmouse · Post by **Flyingmouse** » Tue Sep 21, 2010 1:19 am

Another question...

I need to add another byte after 051D (or 051E, doesn't make much of a difference) in Keen 3- I need three, but the function has only two. What do I do here?

levellass · Post by **levellass** » Tue Sep 21, 2010 2:00 am

...

WHY?

Flyingmouse · Post by **Flyingmouse** » Tue Sep 21, 2010 9:23 pm

Just an idea I had... may use it in a mod. (provided I even finish one)

Or, perhaps, I'm just insane.

levellass · Post by **levellass** » Wed Sep 22, 2010 9:38 am

Yes, but what for? If we know what it's for then possibly there are other ways of doing it.

Flyingmouse · Post by **Flyingmouse** » Wed Sep 22, 2010 11:57 am

To be exact, getting an extra life would do the opposite- killing you. I would need 3 bytes to use the Vorticon interaction.