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Date: Thu, 1 Nov 2012 13:58:35 +0530
From: Sayantan Datta <std2048@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: DES bitslice sboxs for GPUs (not AMD)

Hi alain,

On Thu, Nov 1, 2012 at 9:41 AM, Alain Espinosa <alainesp@...il.com> wrote:

> The sboxs in src/nonstd.c contains ANDN instructions that are not
> available in GPUs (if i read and understood the documentation). Of
> course we can convert ANDN to a AND plus a NOT, but i guess there are
> optimized sboxs without ANDN.
>

I'm not sure but I don't think there are any other sboxes other than these
two for DES.  If  the GPUs don't have andn instruction then the compiler is
probably doing the same AND + NOT but that may not be using least number of
instructions. So optimizing might involve a lot of boolean manipulations.


Regards,
Sayantan

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