Cheat Engine

[Dr.Disrespect]

I have read some tutorials, and they say the way of defining a byte variable in assembly language is:

[STN]

Both but you should listen close and understand it more clearly. I don't know why you would assume an assembly programming language will have similar syntax to a tool made for gamehacking. I guess you need more reading up on what an assembler, compiler, linker etc are for you to understand this.

Anyhow, you can define a variable/symbol in CE several ways

var:
db/dd/dq 0

or

label()
registersymbol()

or

label() // local scope i.e limited to the script in wich defined

or

allocating memory like you did.

CE does NOT actually define a variable by itself like a programming lang does but you have to tell CE YOURSELF where the variable or more appropriately where the symbol is pointing to. The way you do that is you define an address and below that define your var/symbol like this

92ace:
var:
db 0

or

newmem:
var:
db 0

As a matter of fact you dont need the db 0 part, this is just initializing.

[Dr.Disrespect]

[ParkourPenguin]

No. A label is only a representation of an address in memory. That address has to exist in order for it to be valid. You are responsible for assigning the memory address of the label yourself.

All memory CE allocates is always filled with the byte 00. Therefore, you don't always need to write some memory to an address if all you're going to be writing is 0 anyways. However, you still may need to. Take this for instance:

[Zanzer]

If you only want to declare a single 4-byte variable, you can:

[Dr.Disrespect]

@ParkourPenguin
@Zaner

OMG, you guys are so awesome. I really appreciate your help like I always do. Both of your explanations really help me figure out what is going on with the "alloc", "label" and the interaction between memory location and labels etc. Those are among the best guides I have ever read. Thank you both so much.

PS: where can I find this kind of information or how do you know this? I really want to learn.

[ParkourPenguin]

I learned all of this primarily through trial and error. I got the basics down from some random tutorials online, but those don't truly teach you that much. What really helped me learn was finding something I wanted to do in some game and using Google to figure out how to do it. Looking at already existing asm in processes themselves is a (usually) good source of example code. Google anything you don't know, and if you don't understand the explanation, google that too.

The templates CE makes for you are helpful and mostly self-explanatory if you understand the relevant concepts of computer science going on (e.g. what is memory, what are bytes, what is asm), so that was never that much of a problem for me. CE's help file (under the help menu) has information on all the functions you can use in an AA script (e.g. assert, readmem, etc.). Downloading and looking at other people's AA scripts is (usually) a good source of examples.

[Dr.Disrespect]

[blueboy90780]

[Corroder]

I am also newbie with AA and starting to learn (while continue learning lua).

[SunBeam]

Hi Corroder. A few things you should know:

1. alloc( x, 1..1024 ) or alloc( x, 0x1..0x1000 ) will allocate 0x1000 (that is 1024) bytes in memory. If, for example, you give it 1025 or 0x1001, it will allocate 2048 (0x2000). If you want to allocate the exact amount, I think you can use globalalloc. See more here: http://wiki.cheatengine.org/index.php?title=Cheat_Engine:Auto_Assembler.

2. Cheat Engine 6.6 doesn't necessarily require label( x ) to exist for you to use a label It's best practice to still declare it, to keep track, but you can very well omit it.

For the rest of it, you are correct.

Also, remember to unregistersymbol and dealloc (in FILO style: first-in last-out) in the [DISABLE] part of the script:

[Corroder]

Hi SunBeam,

Thank so much for quick replay and also some important information's.
Before this i didn't know if allocate > 1025 or 0x1001 it will allocate as 2048 or 0x2000 (2 MB), then i guess if > 2049 or 0x2001 will allocate as 3072 or 0x3000 and so on...

And also for, CE 6.6 doesn't necessarily require label( x ) to exist for us to use label.

Of course I need learn by read some tutorials, references, get and understand some samples and the important thing is, run some trials and errors. Soon will practice how to implementation, AA script to a simple real game, something like windows pinball, etc. Just to get how it work and clearly understand about using AA.

Thanks and BR...

[SunBeam]

Correct with the allocations

[ParkourPenguin]

[SunBeam]