Re: [PATCH 06/13] async_tx: add support for asynchronous GF multiplication

From: H. Peter Anvin
Date: Fri Mar 20 2009 - 22:31:40 EST


Ilya Yanok wrote:
>
> async_gen_syndrome() takes element of GF^n(256) and returns result of
> scalar multiplication of it with constant ({01}, {02}, {02}^2, ...,
> {02}^n) vector.

For any n (which would mean any GF field)? In that case, that is
generic scalar-vector multiplication...

> async_pq() takes two vectors from GF^n(256) and returns their scalar
> multiplication.
>
> We need async_pq() function if we want to offload D_x = A * (P + P_{xy})
> + B * (Q + Q_{xy}) part of DD recovery and D_x = (Q + Q_x) * g^{-x} part
> of DP recovery.


No, you don't. A and B (and g^{-x}) are scalars, meaning they're the
same for every element. This is simpler to do.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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