From: "Kevin D. Kissell" <kevink@mips.com>
To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>,
"Ralf Baechle" <ralf@linux-mips.org>
Cc: "Gilad Benjamini" <yaelgilad@myrealbox.com>, <linux-mips@linux-mips.org>
Subject: Re: lwl-lwr
Date: Wed, 21 May 2003 15:40:25 +0200 [thread overview]
Message-ID: <007a01c31f9e$8a784ee0$10eca8c0@grendel> (raw)
In-Reply-To: Pine.GSO.3.96.1030521115345.2088D-100000@delta.ds2.pg.gda.pl
>From: "Maciej W. Rozycki" macro@ds2.pg.gda.pl
>
> On Wed, 21 May 2003, Ralf Baechle wrote:
>
> > > There's really no such thing as "disabling" lwl/lwr. They are part
> > > of the base MIPS instruction set. If one wants to live without them,
> > > one can either rig a compiler to emit multi-instruction sequences instead
> > > of lwr/lwl to do the appropriate shifts and masks (which is slower on all
> > > targets), or you can rig the OS to emulate them, and hope that the processors
> > > lacking support will take clean reserved instruction traps, where the function
> > > can be emulated (which is "free" for code running on CPUs with lwl/lwr,
> > > but *really* slow for the guys doing emulation).
> >
> > Technically you're right ... In reality lwl/lwr are covered by US patent
> > 4,814,976 which would also cover a software implementation. So unless MIPS
> > grants a license for the purpose of emulation in the Linux kernel ...
>
> For practical reasons I believe it can be dealt with without patent
> infringing, but I am not that excited with doing anything at all about it.
I agree. I've never read the patent, but now that you mention it, I do
recall having heard that it covers software implementations. Lets just
leave this one alone...
Kevin K.
WARNING: multiple messages have this Message-ID (diff)
From: "Kevin D. Kissell" <kevink@mips.com>
To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>,
Ralf Baechle <ralf@linux-mips.org>
Cc: Gilad Benjamini <yaelgilad@myrealbox.com>, linux-mips@linux-mips.org
Subject: Re: lwl-lwr
Date: Wed, 21 May 2003 15:40:25 +0200 [thread overview]
Message-ID: <007a01c31f9e$8a784ee0$10eca8c0@grendel> (raw)
Message-ID: <20030521134025.lEc3Q5W-jilk0tbPNJy8l5mMxmoOE3Md24xeA6kme2Y@z> (raw)
In-Reply-To: Pine.GSO.3.96.1030521115345.2088D-100000@delta.ds2.pg.gda.pl
>From: "Maciej W. Rozycki" macro@ds2.pg.gda.pl
>
> On Wed, 21 May 2003, Ralf Baechle wrote:
>
> > > There's really no such thing as "disabling" lwl/lwr. They are part
> > > of the base MIPS instruction set. If one wants to live without them,
> > > one can either rig a compiler to emit multi-instruction sequences instead
> > > of lwr/lwl to do the appropriate shifts and masks (which is slower on all
> > > targets), or you can rig the OS to emulate them, and hope that the processors
> > > lacking support will take clean reserved instruction traps, where the function
> > > can be emulated (which is "free" for code running on CPUs with lwl/lwr,
> > > but *really* slow for the guys doing emulation).
> >
> > Technically you're right ... In reality lwl/lwr are covered by US patent
> > 4,814,976 which would also cover a software implementation. So unless MIPS
> > grants a license for the purpose of emulation in the Linux kernel ...
>
> For practical reasons I believe it can be dealt with without patent
> infringing, but I am not that excited with doing anything at all about it.
I agree. I've never read the patent, but now that you mention it, I do
recall having heard that it covers software implementations. Lets just
leave this one alone...
Kevin K.
next prev parent reply other threads:[~2003-05-21 13:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-20 18:32 lwl-lwr Gilad Benjamini
2003-05-20 18:34 ` lwl-lwr Will Jhun
2003-05-20 19:07 ` lwl-lwr Kevin D. Kissell
2003-05-20 19:07 ` lwl-lwr Kevin D. Kissell
2003-05-21 0:34 ` lwl-lwr Ralf Baechle
2003-05-21 9:56 ` lwl-lwr Maciej W. Rozycki
2003-05-21 13:40 ` Kevin D. Kissell [this message]
2003-05-21 13:40 ` lwl-lwr Kevin D. Kissell
2003-05-21 12:49 ` lwl-lwr Alan Cox
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