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Date:      Fri, 01 Nov 1996 16:56:00 +0000
From:      Matt Thomas <matt@lkg.dec.com>
To:        Terry Lambert <terry@lambert.org>
Cc:        msmith@atrad.adelaide.edu.au (Michael Smith), freebsd-hackers@freefall.freebsd.org
Subject:   Re: VM answer requested 
Message-ID:  <199611011656.QAA14425@whydos.lkg.dec.com>
In-Reply-To: Your message of "Fri, 01 Nov 1996 11:42:21 MST." <199611011842.LAA28151@phaeton.artisoft.com> 

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> What about the aligned access bit in recent Intel processors?
> 
> I'd like to be able to turn on the bit so that I get a fault (and it
> kills the offending process) when an unaligned access occurs.
> 
> I'd also like to get kernel faults if this happens in the kernel
> (it is my opinion that it should never be allowed to happen in the
> kernel, and there should be a sanitization pass to insure it).

Don't use the de driver then.  Because of a misfeature in the 21x4x 
chips, the Ethernet payload (the stuff after the header) is not longword
aligned).  Having the processor deal with unaligned data is much faster
than copying the data so that it is aligned.
-- 
Matt Thomas               Internet:   matt@3am-software.com
3am Software Foundry      WWW URL:    http://www.3am-software.com/bio/matt.html
Westford, MA              Disclaimer: I disavow all knowledge of this message





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