From: sandmann AT clio DOT rice DOT edu (Charles Sandmann)
Message-Id: <10303121800.AA20040@clio.rice.edu>
Subject: Re: Getting CRx registers
To: djgpp-workers AT delorie DOT com
Date: Wed, 12 Mar 2003 12:00:15 -0600 (CST)
In-Reply-To: <09e801c2e8ac$6685f830$0600000a@broadpark.no> from "Gisle Vanem" at Mar 12, 2003 04:31:06 PM
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> Is there a safe way to get the value of the Control Registers
> (CR0-4) under CPL > 0?. 

Not today.  If there were a good reason I would consider adding something
to CWSDPMI to emulate it - but given the large number of DPMI providers
out there, I think this is a bad idea.

If you need these, why not just run under ring 0?

> Under Win-XP "movl %cr4,%eax" seems to be safe (i.e. doesn't crash), 
> but return value is always 0. 

So it's useless.

> Under plain DOS and CWSDMI it crashes.
> I could probably use a SIGILL handler, but try to avoid it.

If it never returns useful information under CPL > 0, don't do it?