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Date: Wed, 21 Mar 2012 13:08:56 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: SSSE3 PSHUFB (was: AMD Bulldozer and XOP)

On Wed, Mar 21, 2012 at 09:49:36AM +0200, Milen Rangelov wrote:
> Yes, it was the SSSE3 PSHUFB instruction. I am not that well acquainted
> with the JtR code,

That's the point - it is an opportunity for you to get more acquainted
with the JtR code.

> so that I guess it would be better if someone that knows
> what he's doing applies such a change.

Long term, it may be better if you get involved with JtR development. ;-)

> The overall idea is very simple - since SHA1 expects input in w[0]...w[15]
> to be in big-endian byte order (and the final result needs to be converted
> to little-endian), we have two options - either do it before we load input
> into xmm registers (slow), or use some bitwise magic with SSE2. What I used
> before was some bit twiddling hack using several bitwise operations. I
> realized that this can be performed using just one PSHUFB instruction, like
> that:
> 
> 
> __m128i swapmask = _mm_set_epi32(0x00010203, 0x04050607, 0x08090a0b,
> 0x0c0d0e0f );

Yes, that's how I understood you.

Thanks,

Alexander

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