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Re: config option vs. run-time detection (the debate continues ...)

To: "Kevin D. Kissell" <kevink@mips.com>
Subject: Re: config option vs. run-time detection (the debate continues ...)
From: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
Date: Sat, 10 Feb 2001 10:05:28 +0100 (MET)
Cc: Jun Sun <jsun@mvista.com>, linux-mips@oss.sgi.com
In-reply-to: <01b001c092e5$58f6a8a0$0deca8c0@Ulysses>
Organization: Technical University of Gdansk
Sender: owner-linux-mips@oss.sgi.com
On Fri, 9 Feb 2001, Kevin D. Kissell wrote:

> The best method I know for post-R3000 CPUs is to
> write and read back the CU1 bit of the Status register.
> CPUs without an integrated FPU will not have a flip-flop
> for the bit, and will read back a 0 even after writing a 1.
> There was never any architectural requirement that
> this be so, however, and this cannot be absolutely
> guaranteed to work.  If anyone has a counter-example,
> however, I'd be interested in hearing about it.

 OK, then we may try to toggle CU1 and only if that succeeds check the FPU
implementation id.  Thanks for the point. 

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +


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