Cheat Engine

blueboy90780

Hello Everyone

So lately, I've been doing a bit of research on "XMM" registers since I've encountered them several times on the debugger/disassemble. After doing some research on XMM registers - I understood nearly 0 things about them besides that they are part of "Single Floating Point Precision".

I was wondering if there is any tutorial in which I can learn how to work with XMM registers in cheat engine. Most of the things I've found are to do with the CPU architecture which I don't really need to know - I just want to know:

- The rules when writing assembly with "XMM" registers
- What makes it special with other registers such as "EBX" or "EAX"
- What Dword,Qword are and how do I use them in my code?
- Using single floating point precision code (addf, movdqu etc etc...)

It'll be great if someone is able to post/find a tutorial that covers all of the above. I find this quite a difficult topic to understand

P:S: I've already watched Stephen Chapman's tutorial on XMM, but he didn't explain much besides the fact that XMM is organized into several registers each differing from bytes.

STN · Posted: Sun Jan 15, 2017 8:14 am Post subject:

I think you need to understand the basics first of 32-bit assembly because it seems you don't understand that to begin with. You are trying to run before you can crawl.

"Most of the things I've found are to do with the CPU architecture which I don't really need to know " - this type of attitude is stupid, registers are part of the architecture, how do you expect to understand the architecture without understanding the architecture?

I'll try to answer your questions briefly

- The rules when writing assembly with "XMM" registers - Same as working with any other registers, refer to asm manual for full list of instructions (google)

- What makes it special with other registers such as "EBX" or "EAX" - EBX/EAX are 32bit registers, xmm is a completely different thing than ebx/eax. They are similar to FPU registers.

- What Dword,Qword are and how do I use them in my code? - Uhh, start from beginning of whatever tut you are following if you don't know the answer to this (don't bother with xmm until you do)

- Using single floating point precision code (addf, movdqu etc etc...) - ^