linux-kernel - Re: [PATCH RFC] reciprocal_divide: correction/update of the algorithm

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Message-ID: <52D5F7BF.7090407@gmail.com>
Date:	Tue, 14 Jan 2014 21:51:43 -0500
From:	"Austin S. Hemmelgarn" <ahferroin7@...il.com>
To:	Borislav Petkov <bp@...en8.de>,
	Eric Dumazet <eric.dumazet@...il.com>
CC:	Hannes Frederic Sowa <hannes@...essinduktion.org>,
	netdev@...r.kernel.org, dborkman@...hat.com,
	linux-kernel@...r.kernel.org, darkjames-ws@...kjames.pl
Subject: Re: [PATCH RFC] reciprocal_divide: correction/update of the algorithm


On 01/14/2014 06:25 PM, Borislav Petkov wrote:
> On Tue, Jan 14, 2014 at 02:45:37PM -0800, Eric Dumazet wrote:
>> Even on a Jaguar, the proposed alternative
> I don't know what Jaguar you guys are talking about but the Jaguar
> I know - Fam16h - has an int hardware divider:
>
> http://developer.amd.com/wordpress/media/2012/10/SOG_16h_52128_PUB_Rev1_1.pdf
>
> So all that talk about microcode is plain wrong. The hardware divider
> comes from Llano (F12h) so it must be some other Jaguar, maybe Bobcat.
>
> :-)
>
> If it is Bobcat, then it has a 1-bit per cycle ucode int divider.
>
Apologies, it does have a hardware divider, however it still only gets 2
bits per cycle.
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