Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!wang!comm.wang.com!lws
From: lws@comm.wang.com (Lyle Seaman)
Newsgroups: comp.unix.questions
Subject: Re: Math Coprocessors
Message-ID: <1990Dec11.230015.24421@comm.wang.com>
Date: 11 Dec 90 23:00:15 GMT
References: <126@mq.com> <1990Nov15.184607.21575@mccc.uucp> <12079@scorn.sco.COM> <42393@sneaky.UUCP>
Organization: Wang Labs, Platform Comms.
Lines: 19

gordon@sneaky.UUCP (Gordon Burditt) writes:

>How, then, is it arranged that process A and process B, both of which use
>floating point, don't stomp all over each other's FPU registers?  It would
>seem that the kernel must minimally load and unload the FPU state when
>necessary due to process switches between processes using the FPU.

It's probably because the kernel is non-preemptable, so the FP operation
runs to completion before the process switch.

>If it doesn't use any floating-point instructions, how does it figure out
>whether the FPU is present?

Does it matter?

-- 
Lyle                      Wang             lws@comm.wang.com
508 967 2322         Lowell, MA, USA       uunet!comm.wang.com!lws
             The scum always rises to the top.