Cheat Engine

[navarone]

how the hell can

xor eax,eax

Access an address?

[Dark Byte]

it doesn't
but perhaps it indirectly changes an address somewhere else

[navarone]

Indirectly how exactly..?

eax just changed to 0, that's all.

[Dark Byte]

perhaps some other code writes eax to memory

[navarone]

..Like another thread?

Or should I scroll down the op codes to see where eax finally gets written to the memory?

[Dark Byte]

yes, most likely further down eax will get written to the memory

of course, if this was just a function you're replaced (xor eax,eax followed by a ret xxxx) it means that eax will be written from the location that called the function

[navarone]

Why the abnormal behavior though, I mean if eax is later going to be wrote into that address, why didn't break where it directly changes the address instead?
Sorry, I don't normally ask questions like these a lot, but this behavior is just weird =p

[Dark Byte]

probably an easier spot to get into.

e.g check the jumplines, if you overwrite instructions that are pointed to by a jumpline inbetween you will cause a crash

so in some cases it's easier to just do the hook a bit earlier, and ending up with the same result

[navarone]

I will look into the code again and see for myself

Thank a lot DB again =]

[justa_dude]

I may be wrong, but I think that depending on how the code is aligned CE may not be disassembling it correctly - or at least not displaying it properly. This happens to me sometimes, such that just hitting page up and then page down causes the code listing to become garbage.

Cheers,
adude