Cheat Engine

HenryEx

So i'm working on a table with a big single script that has several optional functions. I'm currently allocating a byte "flag" for every function and let the code check whether the value is zero or not.

Since CE can actually read/display single bits, i want to try my hand at a bit array for these On/Off switches, but i'm not sure how i can actually check the value of a certain bit conveniently and quickly. Do i shift the register left and right to isolate the bit? Or do i AND with the value to expect?

Currently i'm doing:
cmp byte ptr [FlagAddress],00
je _BackToCode

Is there anything as simple as that?

Also, another question. I'm not sure if this can be done in Auto Assembler. You can assign scripts to hotkeys, right? I want to save certain values in memory (coordinates, ca. 50 bytes) to an address i have allocated myself by pressing a hotkey. Then i want to load these coordinates from the allocated space back into the game memory with another hotkey.

How would i go about doing this? It seems that, with AA scripts, i always have to rely on the game to execute the code i write.

Dark Byte · Posted: Fri Jan 13, 2012 1:39 pm Post subject:

you could use the "test" command instead of cmp to set the eflags

the ZF flag gets set if (result1 AND result2)== 0
meaning, it gets set if the flag was NOT present in the value

e.g:

HenryEx · Posted: Sat Jan 14, 2012 3:01 pm Post subject:

Thanks, "test" works pretty good and it's short to boot!

Now here's a marginally more complex situation, where i need to check the status of two flags and then decide where to go. There's options for one flag, the other flag, or both at once. Things suddenly got a lot more complicated, since i can't just check if test returns zero.

This is how i solved the problem for now:

Dark Byte · Posted: Sat Jan 14, 2012 9:40 pm Post subject:

I think you can use "test" here as well so it doesn't modify any register except the eflags, but will be about as long, but probably easier to read

HenryEx · Posted: Sat Jan 14, 2012 9:54 pm Post subject:

Thanks for the tip about saving flags.

Also, correct me if i'm wrong, but "test" is basically a logical AND that doesn't save the result, right? So if i AND 1 and 3...

Dark Byte · Posted: Sat Jan 14, 2012 10:28 pm Post subject:

Ah yes, you're right

I think the only solution is to use registers then(or compare against all byte combinations that have one or both of the bits set...)
Not really a problem as long as you keep track of the registers you use (you don't have to use al, you can use any other register as well)

HenryEx · Posted: Sat Jan 14, 2012 10:57 pm Post subject:

It now occurs to me that i could still use test if i reorder the checks like so:

Dark Byte · Posted: Sat Jan 14, 2012 11:00 pm Post subject:

Hmm, this won't work

if bArray1+1 has both flags set it will jump to _first as well