Re: [PATCH] __div64_32: implement division by multiplication for 32-bit arches

From: Nicolas Pitre
Date: Fri Oct 30 2015 - 12:55:46 EST


On Fri, 30 Oct 2015, Alexey Brodkin wrote:

> Hi Nicolas,
>
> On Fri, 2015-10-30 at 11:17 -0400, Nicolas Pitre wrote:
> > On Fri, 30 Oct 2015, MÃns RullgÃrd wrote:
> >
> > > Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> writes:
> > >
> > > > OK... I was intrigued, so I adapted my ARM code to the generic case,
> > > > including the overflow avoidance optimizations. Please have look and
> > > > tell me how this works for you.
> > > >
> > > > If this patch is accepted upstream, then it could be possible to
> > > > abstract only the actual multiplication part with some architecture
> > > > specific assembly.
> > >
> > > Good idea.
> >
> > Could you please provide a reviewed-by or acked-by tag?
>
> Sure!
>
> Acked-by: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
>
> BTW I thought about that optimization a bit more and now I think
> we may even skip addition of arch-specific assembly insertions.

I'm going to do it anyway given that I already have it for ARM. It'll
be opt-in, so if your arch doesn't provide it then the current C
implementation will be used by default.


Nicolas