Cheat Engine

SpaceUrkel · How do I cheat? Reputation: 0 Joined: 25 Feb 2012 Posts: 8

Hey, new forummember here! How is it going, people?

I have a question for all you ASM-cracks out there, I am currently (lies)
trying to get into ASM and debugging and its fairly okay to learn, but there
are a few things that google won't answer me instantly and just keeps
bugging me.

For example:
Why do 32/64-bit program still use segment registers like ds,ss,es?
I can perfectly store every address in one of the effective registers
(i.e. eax,ebx,ecx,edx,edi,esi)...

I am using OllyDBG on Win7. Thanks
-SpaceUrkel Very Happy

Dark Byte · Posted: Sat Feb 25, 2012 3:19 pm Post subject:

First of for security. Code running in a usermode code segment can not access kernelmode pages

Second, for distinguishing between 16, 32 and 64-bit code, and data access.

Third, for making software development easier. A segment register can have a base address. So accessing fs:[0] accesses the first byte of that base. This can be used for thread specific information so threads do not need to know where the thread information is stored(in case of fs:[0] it's related to exception handling)

SpaceUrkel · How do I cheat? Reputation: 0 Joined: 25 Feb 2012 Posts: 8

Okay, so for 32/64 bit programming it's more of a convenience than an essential, i take?

Dark Byte · Posted: Sat Feb 25, 2012 3:40 pm Post subject:

It's still required for protection, but that's mainly goverened by the os and not the app
But ,in 64 windows you can use it to execute 64 bit code in a 32 bit process, and the other way around

SpaceUrkel · How do I cheat? Reputation: 0 Joined: 25 Feb 2012 Posts: 8

Thanks for the help. Smile