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Date: Thu, 24 Mar 2005 09:37:31 -0600
From: Dan Nelson <dnelson@allantgroup.com>
To: klowd9 - <klowd92@hotmail.com>
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cc: freebsd-hackers@freebsd.org
Subject: Re: Kernel documentation and specification
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In the last episode (Mar 24), klowd9 - said:
> Where can i find resources about the freebsd kernel? I read over the
> developers handbook, and the architecture handbook, and both provide
> very little information i need. Also if anyone can recommend irc
> channels to visit where developers are to be found. I visited
> #BsdCode of efnet, but it was keyed not too long ago.
> 
> Some questions for instance are the use of sse, mmx, and fpu register
> and commands inside the kernel.

To answer this particular question, I don't believe any floating-point
is allowed in the kernel, due to the extra time it would take to save
and restore the registers on every context switch (and kernel thread
switch even), and the difficulty of trapping exceptions.

-- 
	Dan Nelson
	dnelson@allantgroup.com