#if (NTDDI_VERSION >= NTDDI_VISTA)
extern NTSYSAPI volatile CCHAR KeNumberProcessors;
#elif (NTDDI_VERSION >= NTDDI_WINXP)
extern NTSYSAPI CCHAR KeNumberProcessors;
#else
extern PCCHAR KeNumberProcessors;
#endif

DWORD_PTR KeNumberProcessors = 0x80564321;
DWORD_PTR dsKeNumberProcessors = (DWORD_PTR)&KeNumberProcessors;
__asm {
    push eax
    mov eax, dsKeNumberProcessors
    mov al, [eax] // only affects AL -> AL := 0x21
    cmp al, 0x40
    movsx eax, al // completely garbles EAX
    pop eax
};