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From: theall@rm105serve.sas.upenn.edu (George A. Theall)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: 386 vs 386SX
Message-ID: <34538@netnews.upenn.edu>
Date: 11 Dec 90 14:23:33 GMT
References: <6242@crash.cts.com>
Sender: news@netnews.upenn.edu
Organization: University of Pennsylvania
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In article <6242@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes:
>There is no way in software to tell the
>difference between the 386SX and 386DX.

   Recently there was a short piece of code posted to comp.sys.intel by
danw@jacobs.cs.orst.edu (Dan Whitaker) which claimed to tell the
difference when run on some type of 386 (ie, it's not for XTs or ATs).
Though I don't understand the test it employs, it has successfully
reported the CPU type when run on several IBM PS/2 Model 80s and 55SXs
and an NEC PowerMate SX with which I work.

   I make no claims that the algorithm used is valid for all machines
or configurations. Nonetheless, a slightly reformatted version of
Whitaker's code is attached below for those who might be interested yet
missed the earlier article. It is coded for TASM and will *not* run
under either DESQview or Turbo Debugger! I'd appreciate hearing of your
experiences with it, especially if it does *not* work in a particular
configuration.

		--- snip, snip, snip ---
;---------------------------------------------------------------------------;
; Article 1406 of comp.sys.intel:
; From: danw@jacobs.cs.orst.edu (Dan Whitaker)
; Subject: CODE that can tell a 386DX from a 386SX
; Date: 22 Oct 90 22:24:27 GMT
; Organization: Oregon State University - CS - Corvallis Oregon
;
; For all of you that have been looking for a fool proof way to
; tell a 386DX from a 386SX, there it is. (Source code included)
;
; Dan Whitaker   wk (503) 757-0934  FAX (503) 757-7350
;---------------------------------------------------------------------------;

   DOSSEG
   .MODEL MEDIUM
   .386P
   .STACK 100h
   .DATA
have386dx DB 'You have a 386DX',13,10,'$'
have386sx DB 'You have a 386sx',13,10,'$'
   .CODE
   mov  eax,CR0                 ;Read in the CR0 register
   and  eax,0ffefh              ;set the 5th bit to 0
   mov CR0,eax                  ;write out modified register to reset CR0
   mov eax,CR0                  ;Read it back in to see if it changed
   and eax,00010h               ;set register to 0 if 5th bit was zero
   jnz sxchip                   ;see if it is sx
   mov ax,@data                 ;lets display the dx message
   mov ds,ax                    ;set DS to point to the data segment
   mov ah,9                     ;DOS print string function
   mov dx,OFFSET have386dx      ;point to dx message
   int 21h                      ;display the message
   jmp exit
sxchip:
   mov  ax,@data
   mov  ds,ax                       ;set DS to point to the data segment
   mov  ah,9                        ;DOS print string function
   mov  dx,OFFSET have386sx         ;point to sx message
   int  21h                         ;display message
exit:
   mov  ah,4ch                      ;DOS terminate program function
   int  21h                         ;terminate the program
   END
		--- snip, snip, snip ---


George
--- 
theall@rm105serve.sas.upenn.edu			Dept. of Economics
theall@ssctemp.sas.upenn.edu			Univ. of Pennsylvania
gtheall@penndrls.upenn.edu			Philadelphia, PA 19104