Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rutgers!att!watmath!maytag!looking!brad From: brad@looking.on.ca (Brad Templeton) Newsgroups: comp.os.msdos.programmer Subject: Re: Detecting an 80486 Message-ID: <1990Jul20.193422.3922@looking.on.ca> Date: 20 Jul 90 19:34:22 GMT References: <1990Jul19.025150.6150@looking.on.ca> <104096@convex.convex.com> Distribution: comp.os.msdos.programmer Organization: Looking Glass Software Ltd. Lines: 20 Beware of the 486 detection method given in PC Magazine July 1990. I just tried it, and attempts to access the 386 control register will cause you to trap and abort in protected mode DOS systems like DOS-Merge. So far the only two methods I have had suggested are the method of PC Magazine (try to set the cache write through bit in CR0 and see if you did it) and the trap the Int 6 illegal OP trap yourself, and then try to execute a 486 instruction. See if you trap. I don't like either of those methods. Perhaps I will see if a test like PC magazine's will work if you make sure that you don't do it in virtual 8086 mode. You do want to know if you have an 386 in virtual 8086 mode, because you can still use 32 bit registers in that mode. I don't know if there's any special 486 power you would want in virtual 8086 mode or not. -- Brad Templeton, ClariNet Communications Corp. -- Waterloo, Ontario 519/884-7473