Cheat Engine

danrevella · Posted: Fri Apr 10, 2015 5:53 am Post subject: writeInteger() sometime fails

Hi!!
suppose I have attacched the VEH debugger at program "test.exe"
This code work OK!!!

ZacTheSin · Posted: Fri Apr 10, 2015 6:52 am Post subject:

Are you calling the function somewhere not in your code displayed?

like just running debugger_onBreakpoint()

danrevella · Posted: Fri Apr 10, 2015 8:38 am Post subject:

Dark Byte · Posted: Fri Apr 10, 2015 9:23 am Post subject:

make sure the breakpoint is after the write, else when you continue the value you wrote will be undone

danrevella · Posted: Fri Apr 10, 2015 9:46 am Post subject:

Zanzer · Posted: Fri Apr 10, 2015 1:13 pm Post subject:

What Dark Byte was pointing out is that if you set your breakpoint on the following instruction:
mov [ebx],eax

And your code essentially writes a value into the same address of EBX...
Then your code will execute, followed by the normal game code...
Overwriting whatever you just put into [ebx] with what was in EAX.
So you should set your breakpoint on the instruction AFTER mov [ebx],eax

Also, I know LUA has access to the registers, but I don't know if it can update them.
Instead of writeInteger(), try simply "EAX = 55". Will that work Dark Byte? Smile

Dark Byte · Posted: Fri Apr 10, 2015 2:00 pm Post subject:

EAX=55 will work yes

danrevella · Posted: Fri Apr 10, 2015 2:50 pm Post subject:

Ok, I understand the point about overwriting...
BTW, (and please excuse for my very poor english...) what I need is the follows:
I have set a "permanent" breakpoint f.e. at Test.exe+0x2120, and I want that every time breakpoint is reached, the memory location at f.e.: "test.exe+1d090" is filled with the fix value of 0x55.
I have defined this in my code with:
writeInteger(ind_val_numerico,55)
but seem to be that inside the function debugger_onBreakpoint() is possible execute many type of code, f.e. about setting register, etc, but seem to be impossible write a value to a memory location, at least in the mode I have definited the code (please look at the top of the post: code NOT working)

Thanks...

Dark Byte · Posted: Fri Apr 10, 2015 3:03 pm Post subject:

use fullAccess(address, size) to make read only sections writable first

Zanzer · Posted: Fri Apr 10, 2015 3:07 pm Post subject:

Copy (CTRL+C) the instruction at Test.exe+0x2120 and the one after it so we can see where you're setting the breakpoint.

As we've said, chances are the game is directly overwriting the value you just wrote into that integer.

Or the instruction at Test.exe+0x2120 is not executing like you think and so your code is never run.

danrevella · Posted: Fri Apr 10, 2015 4:07 pm Post subject:

here is the test prog with the (not)working table.
File is really tiny
https://www.sendspace.com/file/ac6l3u
I woul like to precise that the file test.exe was original supplied on the old cheat prog: Magic Trainer Creator by Olivier Pasqualini.