>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.
