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

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Message-ID: <20140114232538.GD29887@pd.tnic>
Date:	Wed, 15 Jan 2014 00:25:38 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Austin S Hemmelgarn <ahferroin7@...il.com>,
	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 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.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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