Assembly
Issues the CPUID instruction to fetch the family, model and stepping ID
Issues the CPUID instruction to fetch the family, model and stepping ID ; pentid.asm ; ; this program issues the CPUID instruction (valid only on Pentium class ; processors!) and prints three hex digits which correspond to the ; family, model, and stepping ID. If you run this on a 8088, 80386, or ; 80486 processor, it will return to the command line without printing ; anything. If you run this on an 80286, NEC V20 or NEC V30, your machine ; will probably crash. If you're smart enough to run this program only ; on Pentium machines, you can remove all the code between Start and ; RealTest and you'll reduce the code size from 84 to 49 bytes. ; ; TASM /m2 pentid ; two pass mode ; TLINK /Tdc pentid ; link as COM file ; .MODEL tiny .586 ; allow Pentium instructions .CODE ORG 100h Start: pushf ; assure this is a Pentium pop ax ; flags in ax rol ah,1 ; put EFLAGS reserved bit 15 in CF sahf ; store in regular flags jc BailOut ; if carry flag set, it's an 8088! ; assume we're 80386+ (80286 users prepare for crash) pushfd ; push EFLAGS pop eax ; now pull them into reg mov ecx,eax ; save original copy in ECX xor eax,00200000h ; flip bit 21 (CPUID capable) push eax ; pass altered flags back on stack popfd ; allow cpu to balk pushfd ; see what it did with our flag pop eax ; let's test... cmp eax,ecx ; if bit can't be flipped it's je BailOut ; not a Pentium processor RealTest: ; xor eax,eax ; clear eax inc al ; put a 1 in eax cpuid ; opcode is 0fh 0a2h mov bx,ax ; save the lower 16 bits call hex ; convert low nybble (step ID) mov ah,'$' ; add terminator char push ax ; put it on stack mov ax,bx ; recall other bits shr al,4 ; get 'em all lined up call hex ; convert middle nybble (model) xchg al,ah ; swap results call hex ; convert third nybble (family) push ax ; put that on stack, too mov dx,sp ; print the stack (!) mov ah,9h ; print string function int 21h ; DOS interrupt pop eax ; restore stack mov al,bl ; recall original value BailOut: mov ah,4Ch ; terminate program with int 21h ; model & stepping ID as errcode ; ; convert low nybble of al to ASCII char. ; al = {00h - 0Fh } becomes al = { '0'-'9', 'A'-'F' } ; hex proc and al,0Fh ; use only low nybble in al cmp al,0Ah ; set CY flag appropriately sbb al,69h ; al = al - 069h - (al > 10) das ; al = 30h-39h or 41h-45h ret ; pass back our result hex endp END Start
Issues the CPUID instruction to fetch the family, model and stepping ID
