Cheat Engine

[ciglipaf]

i need to calculate distance between my_posx and target_posx in assembly. Can you help me?

pseudo pseudo code:

substract target_posX from my_posX, take square of it, write the result to distanceX²
substract target_posY from my_posY, take square of it, write the result to distanceY²
Sum distanceX² and distanceY², take square root of it, write result to distance

[gameplayer]

I only know how to use FPU instructions. Use dword ptr if the values are float types. Use qword ptr if the values are double types.
fld dword ptr [target_posX_address] //load a float value into FPU stack
fsub dword ptr [your_posX_address] //substract
fmul st(0) //square of previous result
fstp dword ptr [storage_address]
do the same with the y-coordinator

[ciglipaf]

Thanks for help.
Actually i dont really know how stacks works. push pop, fst/fstp, fmul/fmulp... As i understand, they work like this. Am i correct?

fld dword ptr [target_posX_address] //load a float value into FPU st(0)
fsub dword ptr [your_posX_address] //substract this value from st(0), write result to st(0)
fmul st(0) //square of previous result. st(0)=st(0)*st(0)
fstp dword ptr [storage_address] //write st(0) to this adress and remove st(0) from the stack. so now, st(1) becomes st(0), st(2) becomes st(0)...

[gameplayer]

It's correct.

[justa_dude]

When in doubt, like so many other things, it works great to just try it and step through w/ the debugger. You can view the FPU stack and watch how it changes w/ each instruction.

Alternatively, most C/C++ compilers can generate commented assembly code. You might try compiling a very simple C program that does the same calculations into ASM and see how it arranges things. This is very useful anytime you need to write ASM and don't know how to proceed.

[Gniarf]

In reply to the OP: I remember posting that calculation in 3D, it was... there.

[mgr.inz.Player]

If you have two free XMM registers, for example xmm7 and xmm6, you can do this:

[deama1234]

Here's my take on it using the FPU: