I'm trying to reverse the `Dbgv.sys` (x86 kernel driver) for the [DbgView tool][1]. It has this `sub_10D4A` function that is called almost from the beginning of its `DriverEntry`. It goes as such: [![enter image description here][2]][2] The relevant piece of disassembly: .text:00010D64 mov eax, ds:KeNumberProcessors .text:00010D69 mov al, [eax] .text:00010D6B cmp al, 40h ; '@' .text:00010D6D movsx eax, al .text:00010D70 jl short loc_10D74 .text:00010D72 mov eax, [eax] ; <-- line pointed out What I don't understand is the construct that I showed with a red arrow. If `KeNumberProcessors` global variable is larger than or equal to 64 CPU cores (or 40h) it will execute `mov eax, [eax]` instruction, which will try to read a DWORD from an address that is a number of CPUs, say `40h`, which makes no sense. Wouldn't it result in a BSOD? What's the intention there? [1]: https://docs.microsoft.com/en-us/sysinternals/downloads/debugview [2]: https://i.sstatic.net/tdZHp.png