Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!usc!csun!kithrup!sef
From: sef@kithrup.COM (Sean Eric Fagan)
Newsgroups: comp.arch
Subject: Re: Let's pretend
Keywords: Intel, 586, windows
Message-ID: <1990Dec19.052544.3999@kithrup.COM>
Date: 19 Dec 90 05:25:44 GMT
References: <3042@crdos1.crd.ge.COM> <1990Dec18.082623.16648@kithrup.COM> <4748@exodus.Eng.Sun.COM>
Organization: Kithrup Enterprises, Ltd.
Lines: 19

In article <4748@exodus.Eng.Sun.COM> jcb@frisbee.Eng.Sun.COM (Jim Becker) writes:
>There are a whole host of debugging registers in the 486 --  is  there
>any  way  to use them?  One would think that when the chip gets to the
>market  they  would  have  the  debugging  out  of  the way, and those
>registers would be freed up for use by OS and compiler people.

Uhm... the debugging registers on the '486 are (if I understand what you're
talking about) the same as the debugging registers on the '386 (one
addition, I think).  They're used for debugging.  For example, CodeView
under SCO UNIX uses the debugging registers to set data breakpoints (i.e.,
break when this address is read to, or written to, or executed).  They're
not visible to the application, I believe, and can't be used in a multiply
instruction, for example.

-- 
Sean Eric Fagan  | "I made the universe, but please don't blame me for it;
sef@kithrup.COM  |  I had a bellyache at the time."
-----------------+           -- The Turtle (Stephen King, _It_)
Any opinions expressed are my own, and generally unpopular with others.