Post Reply 
Offsets for .prx files
Author Message
Mc Cabe
Storm Trooper

Posts: 1,218.1771
Threads: 177
Joined: 14th Aug 2007
Reputation: 1.43435
E-Pigs: 38.5281
Offline
Post: #1
Offsets for .prx files
How the hell do people find these offsets. (for paf.prx and vshmain.prx etc)

I can't believe any1 finds them at random.

Does any1 want to explain how they find them.

umm?
15/09/2007 09:34 AM
Visit this user's website Find all posts by this user Quote this message in a reply
gsmoke
Noob

Posts: 2,184.2572
Threads: 103
Joined: 14th Apr 2007
Reputation: 1.65351
E-Pigs: 36.9914
Offline
Post: #2
RE: Offsets for .prx files
Well this is not nice at all , like BStronga said , you have to try and change and try and change then you got the PRX corrupted , and try again , for now you can simply start looking the offsets that are already available ...

“Fear not for the future, weep not for the past.”
15/09/2007 09:54 AM
Find all posts by this user Quote this message in a reply
ZiNgA BuRgA
Smart Alternative

Posts: 17,022.2988
Threads: 1,174
Joined: 19th Jan 2007
Reputation: -1.71391
E-Pigs: 446.1274
Offline
Post: #3
RE: Offsets for .prx files
From experience, and corruption etc.

From experience, I know that the PSP stores most of the X/Y positions etc as single precision floating point.
Typically, if I want to see what's in a PRX, just look for values that look like floating point values (there's no magic way to tell if something's floating point - you just have to guess whether something is floating point or not).
Once you find a patch of floats, just corrupt them (overwrite them with random values) to see if anything changes.  If something does, then keep corrupting the area until you narrow it down to a single value - and there, you have the offset.
It can take time, and you never really know if you're going to get anywhere when you start, but it's much faster and easier than reverse engineering...

Alternatively, if you're looking for a particular value, if you can make an estimate of what it is, then you can try searching for that.  For example, I guessed that when you press the volume button, the volume bar stays on screen for 2 seconds.  From experience, I know that time is typically stored as milliseconds, rather than seconds (though the PSP seems to use microseconds sometimes as well).  So when I was asked this - I just searched for a floating point value of 2000 and found it.

I was thinking about a "guide" on tips on how to find these, but the main thing is, experience...
(This post was last modified: 15/09/2007 06:03 PM by ZiNgA BuRgA.)
15/09/2007 06:02 PM
Visit this user's website Find all posts by this user Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 2 Guest(s)

 Quick Theme: