User:Combuster/notepad

These are my notes from experience. PD code, No warranty etc.

Detecting Emulator

perform DIV test: all common flags are maintained. (0000 08D5)

PUSHF
POP EAX
; either clear flags for first test, or set flags for second test. pick one:
; AND AX, (0xffff - 0x8D5)
; OR AX, 0x8D5
PUSH EAX
MOV AX, 5
MOV CL, 2
POPF
DIV CL 
PUSHF
POP EAX
AND EAX, 0x8D5
;AX contains signature

in 16-bit mode, use ax instead of eax

Multiprocessor Bochs

in bochs you have to write MSR_APICBASE before the APIC becomes accessible even though the register already has the correct value