Subject: Re: Odd message....
To: None <franklin@elfie.org, port-alpha@netbsd.org>
From: Ross Harvey <ross@ghs.com>
List: port-alpha
Date: 05/27/1999 13:04:00
> From: John Franklin <franklin@elfie.org>
>
> This evening I found a strange message on my xconsole:
>
> DANGER WILL ROBINSON: FEN SET IN cpu_fork!
>
> Aside from this message, I have no indication of any failures.  I'm
> running netbsd/alpha 1.3.3 on a 3000/300LX.
>
> What does this mean?

To answer your question: FEN is "Floating Enable" and the message is a
non-fatal assertion failure related to the way we do lazy FPU context
switching. The FPU context doesn't switch with the rest of the process
context, rather, the FPU is disabled and the FPU context switch is put off
until the next time a user mode process touches the FPU.

We get this message once in a blue moon, and don't know how to reproduce
it. I've read and read through the code that deals with FEN and the FPU
switch, and it all looks just right. It also doesn't seem to be associated
with any error or any other lossage.

If you can reproduce it, or if it is associated with any kind of failure,
please let me know.

	Ross.Harvey@Computer.Org