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Message-ID: <alpine.LFD.2.20.1510301253140.630@knanqh.ubzr>
Date:	Fri, 30 Oct 2015 12:55:38 -0400 (EDT)
From:	Nicolas Pitre <nicolas.pitre@...aro.org>
To:	Alexey Brodkin <Alexey.Brodkin@...opsys.com>
cc:	"shemminger@...ux-foundation.org" <shemminger@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Vineet.Gupta1@...opsys.com" <Vineet.Gupta1@...opsys.com>,
	"linux-snps-arc@...ts.infradead.org" 
	<linux-snps-arc@...ts.infradead.org>,
	"mans@...sr.com" <mans@...sr.com>,
	"rmk+kernel@....linux.org.uk" <rmk+kernel@....linux.org.uk>,
	"davem@...emloft.net" <davem@...emloft.net>,
	"mingo@...e.hu" <mingo@...e.hu>
Subject: Re: [PATCH] __div64_32: implement division by multiplication for
 32-bit arches

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, Måns Rullgård wrote:
> > 
> > > Nicolas Pitre <nicolas.pitre@...aro.org> 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@...opsys.com>
> 
> 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

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