ditto in the Cog branch.


On Sat, Jan 5, 2013 at 7:23 AM, David T. Lewis <lewis at mail.msen.com> wrote:

> On Tue, Jan 01, 2013 at 03:24:35PM -0500, David T. Lewis wrote:
> >
> > On Tue, Jan 01, 2013 at 03:47:54PM +0000, commits at source.squeak.orgwrote:
> > > Nicolas Cellier uploaded a new version of Kernel to project The Trunk:
> > > http://source.squeak.org/trunk/Kernel-nice.725.mcz
> > >
> > > ==================== Summary ====================
> > >
> > > Name: Kernel-nice.725
> > > Author: nice
> > > Time: 1 January 2013, 4:47:30.911 pm
> > > UUID: 52a4994f-63bc-4f71-9f8f-6f2fad460bde
> > > Ancestors: Kernel-nice.724
> > >
> > > Fast-up large integer modulo operations (\\ and rem:)
> > >
> > > Implementation notes:
> > > Quotient and remainder are computed in a single LargeIntegersPlugin
> primitive (see digitDiv:neg:) so it's faster to just use it.
> > > For LargeInteger with 64 bits or less, LargeInteger primitives (31 32
> 33) are faster than the plugin (especially in COG) so try them first.
> > > This results in a 2x speed up of modulo operations in 4.2.5 VM
> (whatever bit length), and a 2x speed up in COG VM for bit length > 64.
> > > There is a penalty of 15% in COG for #rem: when bit length <= 64
> because there is no primitiveRem...
> > > Well, I added primitiveRem and it is in both VM branches, but it has
> no primitive number assigned.
> > > If we assign a primitive number (20 ?) we can expect a 5x speed up for
> rem and bitLength <= 64.
> >
> > Should we assign primitive number 20 to primitiveRemLargeIntegers? It is
> in
> > the range of numbered primitives allocated for large integer prims, and
> is
> > currently unused in both the interpreter VM and Cog.
> >
> > I can't think of any reason not to do this, so someone please speak up if
> > it might cause problems.
>
> I added primitiveRemLargeIntegers as primitive 20 in VMMaker, so this will
> be available in future builds of the interpreter VM.
>
> Dave
>
>
>


-- 
best,
Eliot
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