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Re: FP emulation patch available

To: "Kevin D. Kissell" <kevink@mips.com>
Subject: Re: FP emulation patch available
From: Harald Koerfgen <Harald.Koerfgen@home.ivm.de>
Date: Tue, 14 Mar 2000 19:15:32 +0100 (MET)
Cc: linux-mips@vger.rutgers.edu, Linux/MIPS fnet <linux-mips@fnet.fr>, Linux SGI <linux@cthulhu.engr.sgi.com>
In-reply-to: <005a01bf8d42$c656d2c0$ec44e8c3@Ulysses>
Organization: none
Reply-to: "Harald Koerfgen" <Harald.Koerfgen@home.ivm.de>
Sender: owner-linuxmips@oss.sgi.com
On 13-Mar-00 Kevin D. Kissell wrote:

[FPU emulator crashes on R3912]

> There are two ways in which the FPU emulator is close enough
> to the hardware to be this sensitive to implementation.  One
> is the way the emulator provokes an address error exception to
> execute a delay slot instruction following a simulated branch, but
> I don't think df or fsck do any branch-on-floating-conditions.  The
> other is, of course, that it counts on getting sensible and recoverable
> coprocessor unusable exceptions.  If the R3912 does something
> funky to the processor state on a CP1 unusable fault - an event
> that it doesn't have to deal with in its principal mission
> as a Windows CE platform - the results would be much
> what you are seeing.

Good Point. Thanks, Kevin, I'll look deeper into that.

-- 
Regards,
Harald

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