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From: mikey@quiche.cs.mcgill.ca (Michael GALLOP)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Detecting an 80486
Message-ID: <3877@quiche.cs.mcgill.ca>
Date: 27 Aug 90 18:56:37 GMT
References: <3839@altos86.Altos.COM> <1990Aug21.223404.19523@ddsw1.MCS.COM> <2664@dataio.Data-IO.COM>
Organization: SOCS - Mcgill University, Montreal, Canada
Lines: 29

In article <2664@dataio.Data-IO.COM> bright@Data-IO.COM (Walter Bright) writes:
>I don't have an 80486 manual, but perhaps a more reliable way to detect
>a 486 would be to detect a difference between an 80487 and a 387. Since
>486's always have a 487 on board, this could work.
>
>Are there any differences between a 387 and a 487?

Ok, here's my 2 cents. There is no difference between a 387 and a 487
The 486 chip is supposed to be a new improved  386 with an internal 8k cache.

In previous postings people have asked why can't the clone manufacturers  put a
'ver' instruction on the chip. Well NOBODY has a working clone of the 386,
let alone a 486. There is a company in California theat is reputadely close
but, in my book close only counts in horse shoes and hand grenades.


There do seem to be, however a few undocumented instructions in the early 
versions of the chip. But who knows?
>
>Are FWAITs *never* necessary with a 487?

In theory no.....But who knows. Odds are they aren't unless you are into 
serious vector prcessing, of more than 32k of instructions. So that the 
cache is full.. but now I'm guessing, I've never run into that problem.
-- 
| mikey@calvin.cs.mcgill.ca | "Life is just a linear Regression to Chaos," |
| Mike Gallop	    	    | "...Poured through a Klein bottle"           |
|        You think my profs know who I am to disclaim me?!??		   |
|"Stealing from one author is plagarism....Stealing from many is research" |