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From: "Kevin D. Kissell" <kevink@mips.com>
To: "Harald Koerfgen" <Harald.Koerfgen@home.ivm.de>
Cc: <linux-mips@vger.rutgers.edu>, <linux-mips@fnet.fr>,
	"Linux SGI" <linux@cthulhu.engr.sgi.com>
Subject: Re: FP emulation patch available
Date: Mon, 13 Mar 2000 09:33:02 +0100	[thread overview]
Message-ID: <002701bf8cc6$c2ef0200$0ceca8c0@satanas.mips.com> (raw)

As Ralf just reminded me by email, the Algorithmics/MIPS
kernel FPU emulator is *not* SMP-safe.  It borrows an existing
(if seldom used) exception handler, and has only a single
set of emulated FPU registers.  I sort-of knew this, but
had not worried about it, since to the best of my knowledge
no one is building (or has built) SMP MIPS machines 
out of FPU-less processors.  Nevertheless, a compile-time
test, to blow up on any attempt at an SMP build of the 
emulator should always have been there, and is going in 
right away.

Does anyone out there actually need/want an SMP
version of the emulator?   It's not completely trivial,
but it would not be all that difficult to do...

            Regards,

            Kevin K.
__

Kevin D. Kissell
MIPS Technologies European Architecture Lab
kevink@mips.com
Tel. +33.4.78.38.70.67
FAX. +33.4.78.38.70.68

WARNING: multiple messages have this Message-ID (diff)
From: "Kevin D. Kissell" <kevink@mips.com>
To: Harald Koerfgen <Harald.Koerfgen@home.ivm.de>
Cc: linux-mips@vger.rutgers.edu, linux-mips@fnet.fr,
	Linux SGI <linux@cthulhu.engr.sgi.com>
Subject: Re: FP emulation patch available
Date: Mon, 13 Mar 2000 09:33:02 +0100	[thread overview]
Message-ID: <002701bf8cc6$c2ef0200$0ceca8c0@satanas.mips.com> (raw)
Message-ID: <20000313083302.SJCbRadcz5EXALtR_hXWH1jwVepq9u5SfcZg74EVNDE@z> (raw)

As Ralf just reminded me by email, the Algorithmics/MIPS
kernel FPU emulator is *not* SMP-safe.  It borrows an existing
(if seldom used) exception handler, and has only a single
set of emulated FPU registers.  I sort-of knew this, but
had not worried about it, since to the best of my knowledge
no one is building (or has built) SMP MIPS machines 
out of FPU-less processors.  Nevertheless, a compile-time
test, to blow up on any attempt at an SMP build of the 
emulator should always have been there, and is going in 
right away.

Does anyone out there actually need/want an SMP
version of the emulator?   It's not completely trivial,
but it would not be all that difficult to do...

            Regards,

            Kevin K.
__

Kevin D. Kissell
MIPS Technologies European Architecture Lab
kevink@mips.com
Tel. +33.4.78.38.70.67
FAX. +33.4.78.38.70.68

             reply	other threads:[~2000-03-13  8:44 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-03-13  8:33 Kevin D. Kissell [this message]
2000-03-13  8:33 ` FP emulation patch available Kevin D. Kissell
2000-03-13 13:46 ` Alan Cox
2000-03-13 13:46   ` Alan Cox
2000-03-13 19:05   ` Harald Koerfgen
2000-03-13 19:05     ` Harald Koerfgen
2000-03-13 17:46 ` Ralf Baechle
2000-03-13 20:13   ` William J. Earl
2000-03-14 18:50   ` Andrew R. Baker
     [not found]     ` <200003142317.XAA00644@gladsmuir.algor.co.uk>
2000-03-15 14:35       ` Kevin D. Kissell
  -- strict thread matches above, loose matches on Subject: below --
2000-03-21 22:27 Kevin D. Kissell
2000-03-21 22:27 ` Kevin D. Kissell
2000-03-13 23:20 Kevin D. Kissell
2000-03-13 23:20 ` Kevin D. Kissell
2000-03-14 18:15 ` Harald Koerfgen
2000-03-12 21:52 Kevin D. Kissell
2000-03-12 21:52 ` Kevin D. Kissell
2000-03-13 22:22 ` Harald Koerfgen
2000-03-12 13:03 Kevin D. Kissell
2000-03-12 13:03 ` Kevin D. Kissell
2000-03-12 21:23 ` Harald Koerfgen
2000-03-08 20:12 Kevin D. Kissell
2000-03-08 20:12 ` Kevin D. Kissell
2000-03-09  2:03 ` Warner Losh
     [not found] ` <200003082223.WAA00605@gladsmuir.algor.co.uk>
2000-03-09  2:13   ` Warner Losh
2000-03-09 20:20 ` Harald Koerfgen
2000-03-08  9:43 Kevin D. Kissell
2000-03-08  9:43 ` Kevin D. Kissell
2000-03-08 17:02 ` Richard van den Berg
2000-03-08 18:43 ` Harald Koerfgen
2000-03-07  4:12 Andrew R. Baker
     [not found] ` <097a01bf87eb$ebe4d4d0$b8119526@ltc.com>
     [not found]   ` <200003071022.KAA00275@gladsmuir.algor.co.uk>
2000-03-07 12:08     ` Jay Carlson
2000-03-07 12:08       ` Jay Carlson
2000-03-08 16:25       ` Ralf Baechle
2000-03-08 16:18     ` Ralf Baechle
     [not found]   ` <38C4C328.9656C68E@niisi.msk.ru>
2000-03-07 18:54     ` Andrew R. Baker
2000-03-07 19:43       ` Harald Koerfgen
2000-03-08 16:11     ` Ralf Baechle

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