Cheat Engine

[Gwinx]

I need to know when to NOP and when NOT TO. TY!

[Innovation]

NOPs are generally used to replace other opcodes with "code that does nothing."

[Radiation]

if you see a line of code that tells the game to subtract ammo every time you shoot, you would nop that line of code which will tell the game to go over to the next instruction, thus skipping the subtraction function. your ammo will never be subtracted. unlimited ammo.


hope i helped

[Seergaze3]

before trying to NOP a code i would recommend you to back it up, in case its something to do with story/cutscene triggers, you could really screw up the game, espically in rpgs

and also, take itapas example, NOP'ing the entire subtract ammo code might also make the enemy also having infinite ammo, so you have to becareful if thats not what you want

[Radiation]

[atom0s]

You're better off avoiding nops as much as possible and actually use code caves instead so you can still allow normal code flow to happen in such cases as mentioned above. Typically nop'ing something is generally useful when you are certain the effect wont break the game/app, only effects what you want it to, and is not some huge mess of replacements.

If you find yourself nop'ing a whole function, find different methods to approach what you are doing. Use jumps, use returns, and so on. No need to write 100 nops when you can just write a simple ret instead. (Ensuring you cleanup the stack and such if the function needs it.)

[Dark Byte]

Also, it's a matter of severity.
Is infinite ammo for an enemy really a problem or not? (Most fps games cheat with that in singleplayer giving them inf ammo anyhow)

for health it is of course a problem yes. The first method I usually go with is compare against the function table pointer in the class, but if it's used by the enemy as well then compare against other stuff like team id's, or finding a pointer to a block that describes the player (structure spider can be useful here)

[haunted5]

Hi,

Just to add a little info,

I normally use CE 'what addresses this code accesses' option to see if the same code is used by multiple addresses and if it is used then a nop might crash the game.

Also I wouldnt Nop a instruction that uses a pop like 'fstp' cause if I Nop that the value reamins on stack and is used by the game later often causing a crash.

Hope this helps