From owner-freebsd-current  Thu Dec  3 11:51:35 1998
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Date: Thu, 3 Dec 1998 11:40:55 -0800 (PST)
From: Julian Elischer <julian@whistle.com>
To: Mark Tinguely <tinguely@plains.NoDak.edu>
cc: freebsd-current@FreeBSD.ORG
Subject: Re: 3.0 and double operations in device drivers
In-Reply-To: <199812031513.JAA18762@plains.NoDak.edu>
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it always was taboo..
floating point operations need a process context to store results etc.
in the case of context changes (e.g. interrupts) etc.
BDE can be more accurate on this point I'm sure.

julian


On Thu, 3 Dec 1998, Mark Tinguely wrote:

> I was testing a device driver that I wrote for FreeBSD 2.2.x on a 
> FreeBSD 3.0-RELEASE. When some double multiplication and divisions
> were executed, the system froze.
> 
> It took a long time to find it was a FP problem, it acted like
> some aweful infinite loop.
> 
> These routines are only used on a circuit setup to calculate some scheduling
> parameters, and I guess they can be done with integer math after some head
> scratching.
> 
> My question is: "Is floating point math now taboo in the kernel?"
> 
> --mark.
> 
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