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.
--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +
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