Cheat Engine

[Nemexia55]

What is the difference between :

Code:

1-mov eax,ebx

Code:

2-mov [eax],ebx

Code:

3-mov eax,[ebx]

Code:

4-mov [eax],[ebx]

please answer me!

[Matze500]

1. Move the content of ebx into eax

2. Move the contents of ebx into the byte at address eax

3. Move the 4 bytes in memory at the address contained in ebx into eax

4. Not possible to move memory to memory

[Nemexia55]

i heard when you use [] it is the value of it (the number stored to)??!!
can you give an example for each one??
i mean:
mov eax,ebx => eax=7|012a ,ebx=9|012b The result => eax=9|012a
is the above true?

[Matze500]

The code above is true.

eax : value=9 address = 210000ac
ebx : value=1 address = 310000ac

For the First

mov eax,ebx

eax : value=1 address = 310000ac
ebx : value=1 address = 310000ac

For the second

mov [eax],ebx

eax : value=1 address = 210000ac
ebx : value=1 address = 310000ac

if somthing is in [] its a memory block and you have acess to its value

[STN]

It is probably much easier to remember when you type it like this

mov dword ptr [eax],ebx

CE already calculates the data type based on registers involved (eax,ebx) but if you were writing in a low level language like tasm/fasm you would use the correct addressing yourself. So its good to always remember like that. Whenever you see dword ptr you know the register or memory address that follows will have its value accessed instead of the value in register itself.

If the instruction misses the brackets [] then the value in the register itself is accessed and not the value inside the address that the register contains.

Do this, debug any program and notice how the value is moved when a certain instruction is executed, you will learn much faster that way than reading and trying to remember it.

[Nemexia55]

thank you very much!
can you explain the third one too??
and i have another question:
what is the difference between (ja and jg) and also (jb and jl)??
please explain like mov

[mgr.inz.Player]

Nemexia55

launch cheatengine, press F1, Now:
Tutorials -> ASM and Hexing Theory -> Basic assembler
(also read "ASM Basics 1", "ASM Basics 2" and "ASM Basics 3")

[Nemexia55]

Thank you very very much!
it explains very good!