arasmith@mathcs.emory.edu (David Arasmith) (10/05/90)
I have a fairly pressing need to learn how to determine CPU type from
inside a C program. I can look at the equipment list etc. to find all
kinds of other hardware in the box but I have NOT been able to find a
good (or not so good) method for CPU detection.
I would greatly appreciate some assistance: pointers, code fragments,
amusing anecdotes.
Email or posting, whatever you feel like (I will get to email faster).
Thanks
--
David M. Arasmith | arasmith@mathcs.emory.edu Internet
Emory University | {sun!sunatl,gatech}!emory!arasmith UUCP
Dept of Math and CS |
Atlanta, GA 30322 | I should be working! Gee....I wonder what's on TV?cjdb@ellis.uchicago.edu (Charles Blair) (10/17/90)
In article <6367@emory.mathcs.emory.edu> arasmith@mathcs.emory.edu (David Arasmith) writes: > >I have a fairly pressing need to learn how to determine CPU type from >inside a C program. I can look at the equipment list etc. to find all >kinds of other hardware in the box but I have NOT been able to find a >good (or not so good) method for CPU detection. > >I would greatly appreciate some assistance: pointers, code fragments, >amusing anecdotes. > >Email or posting, whatever you feel like (I will get to email faster). I'll post an assembly language routine that does this, since I'd like to see an update (this doesn't detect the 486), and since Borland and Microsoft now support inline assembly language (i.e., this might be useful in a C program as well). (I notice that some of the jmp's were better written as jmp short's.) ; GET_CPU - Proc to determine which 80(x)86/8 is installed in a machine. ; Modified from PROC_TYPE, written by Clif Purkiser, Intel, Santa Clara, ; Ca. From the original comment: "The attached code sequence returns ; the processor type in the AX register. It should be distributed to any ; customers and Independent Software vendors who could use it." Also: ; "Note this test works only in Real Mode." The code was captured ; electronically from a posting to Usenet. get_cpu proc near ; ; Returns the processor type in AX ; pushf ; Save FLAG registers xor ax,ax ; Clear AX and push onto the stack. push ax popf ; Pop a zero into FLAGs register pushf ; Attempt to set bit 12-15 to a zero pop ax ; Recover FLAG word and ax, 0f000h ; If Bits 12-15 are then the processor cmp ax, 0f000h ; is an 8018x or an 808x jz gc_is_0_1 mov ax, 07000h ; Try to set FLAG bits 12-14 (NT, IOPL) push ax popf ; put 07000H into flags pushf pop ax and ax,07000h ; if bits 12-14 are cleared then the jz gc_is_80286 ; processor is an 286 gc_is_80386: ; Else it is a 386 mov ax, 386h ; return 386 in AX jmp gc_done gc_is_80286: mov ax, 286h ; return 286 in AX jmp gc_done gc_is_0_1: ; It is a 8086 or a 80186 push cx ; Save CX the only other register used mov ax, 0ffffh ; Set AX to all 1s mov cl, 33 ; will shift it 33 times if it is an ; 808x or 1 time if it is an 8018x shl ax, cl ; if we shift 33 times all bits are jnz gc_is_80186 ; zero. If any bits are on it's an 18x gc_is_8086: ; Else we have an 8086 mov ax,86h ; Return 86 in AX pop cx ; restore cx jmp gc_done gc_is_80186: mov ax, 186h ; Return 186 in AX pop cx gc_done: mov cpu_type,ax ; Store CPU type popf ; Recover original FLAGs register ret get_cpu endp -- Bitnet: pmrcjdb@uchimvs1 Internet: cjdb@midway.uchicago.edu