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cmp function only works for some games? (Problem)

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XaneXXXX
Expert Cheater

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Joined: 29 Nov 2012
Posts: 212

Posted: Fri Aug 28, 2015 9:38 am Post subject: cmp function only works for some games? (Problem)

So I'm trying to write a godmode script for Avp 2010. I have done this many times before for different. Sometimes it works and sometimes not..
In this case the health just keep decreasing.. Here is my code:

Code:

[ENABLE]
alloc(newmem,2048)
label(returnhere)
label(originalcode)
label(health)
label(exit)

newmem:
cmp dword [esi+38],43C30000
je health
jmp originalcode

health:
nop
nop
nop
nop
nop

originalcode:
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere

"AvP_DX11.exe"+146A3C:
jmp newmem
returnhere:

[DISABLE]
dealloc(newmem)
"AvP_DX11.exe"+146A3C:
movss [esi+34],xmm0

it just won't work.. If i nop the function manually it works fine (except that the enemies also have god mode because of the shared instruction).
I've also tried another offset with another compare.

Health still decreasing, does anyone has some idea what it might be? Maybe I'm missing something..

Thanks!

Bl00dWolf
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Joined: 04 Jan 2010
Posts: 79
Location: Russia, Moscow

Posted: Fri Aug 28, 2015 9:41 am Post subject:

UPDATED: deama1234 is right deleted _________________ Sry for my english, Hitler. Last edited by Bl00dWolf on Fri Aug 28, 2015 9:56 am; edited 3 times in total

deama1234
Master Cheater

Reputation: 3

Joined: 20 Dec 2014
Posts: 328

Posted: Fri Aug 28, 2015 9:47 am Post subject:

Code:

health:
nop
nop
nop
nop
nop

originalcode:
movss [esi+34],xmm0
jmp exit

What are you trying to nop? All it does here is execute "movss [esi+34],xmm0" then jumps to exit.

Try this:

Code:

health:
jmp exit

originalcode:
movss [esi+34],xmm0
jmp exit

XaneXXXX
Expert Cheater

Reputation: 0

Joined: 29 Nov 2012
Posts: 212

Posted: Fri Aug 28, 2015 11:07 am Post subject:

deama1234 wrote:

Code:

health:
nop
nop
nop
nop
nop

originalcode:
movss [esi+34],xmm0
jmp exit

What are you trying to nop? All it does here is execute "movss [esi+34],xmm0" then jumps to exit.

Try this:

Code:

health:
jmp exit

originalcode:
movss [esi+34],xmm0
jmp exit

The health function of course. I will try Smile

Stregum
Advanced Cheater

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Joined: 17 Jun 2014
Posts: 56
Location: We make baguettes there !

Posted: Fri Aug 28, 2015 11:26 am Post subject:

deama1234's script should work.

If you want more info about this, here is it, feel free to read it if you want, I had nothing to do anyways ^^.

See this portion of code:

Code:

newmem:
cmp dword [esi+38],43C30000
je health
jmp originalcode

health:
nop
nop
nop
nop
nop

originalcode:
movss [esi+34],xmm0
jmp exit

Technically your cmp is correct, your "health" part isn't correct, it's in fact useless.

What you tried to do is good; "If [esi+38] equals 43C30000, jump to health", that's correct, but your health part does nop's, and theses nops means "Hey computer, do nothing, just waste some time, (actually it does something behind the scenes "xchg eax,eax" : which does nothing in theory)"

So instead of doing these nops, you can remove them, because it's useless.

The real problem is after doing these nops, the cpu executes the next instructions:

Code:

health:
nop
nop
nop
nop
nop

//HERE, THE CPU CONTINUES BELOW, TO "originalcode"

originalcode:
movss [esi+34],xmm0
jmp exit

You HAVE TO tell the cpu to jump over the original code, right after you've done your things

You could do this:

Code:

health:
nop
nop
nop
nop
nop
jmp exit //This jump says "Jump over the original code, DO NOT EXECUTE IT", otherwise, it continues below

originalcode:
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere

Since the nops are useless, you could simplify the code to:

Code:

health: //Remove the nop's
jmp exit

originalcode:
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere

and since there is nothing between 'health' and 'jmp exit', you could simplify even more the code;

Code:

newmem:
cmp dword [esi+38],43C30000
je exit //Exit the script right now, because I want a godmode right ? i don't want to execute fancy stuff that subtracts my health right ?
jmp originalcode

originalcode:
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere

Your final code should look like this; (and don't forget to remove the 'label(health)' if you don't use it

Code:

[ENABLE]
alloc(newmem,2048)
label(returnhere)
label(originalcode)
label(exit)

newmem:
cmp dword [esi+38],43C30000
je exit
//The "jmp originalcode" is useless, because it leads to it if the "je exit" is not executed

originalcode:
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere

"AvP_DX11.exe"+146A3C:
jmp newmem
returnhere:

[DISABLE]
dealloc(newmem)
"AvP_DX11.exe"+146A3C:
movss [esi+34],xmm0

And now it would work. Cheers Smile

, I hope you understand now why it wasn't working (It wasn't the CMP's fault Smile

)
_________________

Rhaa Stregum Vitae Smile

XaneXXXX
Expert Cheater

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Joined: 29 Nov 2012
Posts: 212

Posted: Fri Aug 28, 2015 8:12 pm Post subject:

Stregum wrote:

deama1234's script should work.

If you want more info about this, here is it, feel free to read it if you want, I had nothing to do anyways ^^.

See this portion of code:

Code:

newmem:
cmp dword [esi+38],43C30000
je health
jmp originalcode

health:
nop
nop
nop
nop
nop

originalcode:
movss [esi+34],xmm0
jmp exit

Code:

health:
nop
nop
nop
nop
nop

//HERE, THE CPU CONTINUES BELOW, TO "originalcode"

originalcode:
movss [esi+34],xmm0
jmp exit

You HAVE TO tell the cpu to jump over the original code, right after you've done your things

You could do this:

Code:

health:
nop
nop
nop
nop
nop
jmp exit //This jump says "Jump over the original code, DO NOT EXECUTE IT", otherwise, it continues below

originalcode:
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere

Since the nops are useless, you could simplify the code to:

Code:

health: //Remove the nop's
jmp exit

originalcode:
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere

and since there is nothing between 'health' and 'jmp exit', you could simplify even more the code;

Code:

Your final code should look like this; (and don't forget to remove the 'label(health)' if you don't use it

Code:

And now it would work. Cheers Smile

, I hope you understand now why it wasn't working (It wasn't the CMP's fault Smile

)

This was exactly what i needed! Thank you for your detailed answer, i understand it now! Very Happy

I always thought:
je health
health:
nop
nop
nop
nop
nop
= if "this" is equal, then jump to health, then the "nop" simply does the same as "db/define byte". It replaces the original code with 90 90 90 90 90. But i got it now hehe.

Stregum
Advanced Cheater

Reputation: 0

Joined: 17 Jun 2014
Posts: 56
Location: We make baguettes there !

Posted: Sat Aug 29, 2015 2:24 am Post subject:

Ohh I see

Glad I could help
It took some time to understand for me too, the best way to learn is to inject your code, go to the new allocated region (right click > follow) and see your script in action (with breakpoints if you want) so you know what's happening exactly.

I beleive your method would work if you put the health label below your injection point, like

Code:

module.exe+healthoffset:
health:

The reason health doesn't jump to the original instructions in your script is that the label is below your allocated region (I hope I'm right)

Code:

newmem:
.....
health:
.....

I'm not sure tho, to be verified and tested. I could be wrong.
I never used it that way, and my knowledge level is not at boss level like some people out there Smile

but seems kinda logic (to me at least hehe)
_________________

Rhaa Stregum Vitae Smile

mgr.inz.Player
I post too much

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Joined: 07 Nov 2008
Posts: 4438
Location: W kraju nad Wisla. UTC+01:00

Posted: Sat Aug 29, 2015 3:47 am Post subject:

Using NOP instructions inside allocated memory region ( you used alloc command) is not equal to using "replace with code that does nothing".

Quote:

[ENABLE]
alloc(newmem,2048)
label(returnhere)
label(originalcode)
label(health)
label(exit)

//allocated memory section START (allocated by you)
newmem:
cmp dword [esi+38],43C30000
je health
jmp originalcode

health:
nop
nop
nop
nop
nop

originalcode: // a copy of original code
movss [esi+34],xmm0
jmp exit

exit:
jmp returnhere
//allocated memory section END

//original game memory section
// you overwrite original code with JUMP (and maybe NOPS),
// also you set returnhere variable.
// there might be just JUMP, or JUMP and NOPs (if you used CE AA Template and CE added NOPs here, do not remove them, returnhere will be incorrect without them)
"AvP_DX11.exe"+146A3C:
jmp newmem
returnhere:

[DISABLE]
dealloc(newmem)
"AvP_DX11.exe"+146A3C:
movss [esi+34],xmm0

So, you maybe want to use this:

Quote:

[ENABLE]
alloc(newmem,2048)
label(returnhere)
label(originalcode)
label(health)

//allocated memory section START (allocated by you)
newmem:
cmp dword [esi+38],43C30000
je health

originalcode:
movss [esi+34],xmm0
jmp returnhere

health:
mov [esi+34],(float)100.0 -- set max HP (don't have this game, it's just an example)
jmp returnhere
//allocated memory section END

//original game memory section
"AvP_DX11.exe"+146A3C:
jmp newmem
returnhere:

[DISABLE]
dealloc(newmem)
"AvP_DX11.exe"+146A3C:
movss [esi+34],xmm0

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XaneXXXX
Expert Cheater

Reputation: 0

Joined: 29 Nov 2012
Posts: 212

Posted: Sat Aug 29, 2015 11:06 am Post subject:

mgr.inz.Player wrote:

Using NOP instructions inside allocated memory region ( you used alloc command) is not equal to using "replace with code that does nothing".

Quote:

So, you maybe want to use this:

Quote:

Thanks for all the answers mgr.inz.Player and Stregum! One of the best explanations that I've heard to be honest! Smile

Cheers!

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