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From: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <1365cc84-fdb6-3a36-9b5f-6921f04423e0@linaro.org>
Date: Fri, 12 Apr 2019 13:44:46 -1000
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Subject: Re: [Qemu-devel] [PATCH v1 15/41] s390x/tcg: Implement VECTOR
 GALOIS FIELD MULTIPLY SUM (AND ACCUMULATE)
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To: David Hildenbrand <david@redhat.com>, qemu-devel@nongnu.org
Cc: qemu-s390x@nongnu.org, Cornelia Huck <cohuck@redhat.com>, Thomas Huth <thuth@redhat.com>, Richard Henderson <rth@twiddle.net>

On 4/11/19 12:08 AM, David Hildenbrand wrote:
> A galois field multiplication in field 2 is like binary multiplication,
> however instead of doing ordinary binary additions, xor's are performed.
> So no carries are considered.
> 
> Implement all variants via helpers. s390_vec_sar() and s390_vec_shr()
> will be reused later on.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/helper.h           |   8 ++
>  target/s390x/insn-data.def      |   4 +
>  target/s390x/translate_vx.inc.c |  38 ++++++++
>  target/s390x/vec_int_helper.c   | 168 ++++++++++++++++++++++++++++++++
>  4 files changed, 218 insertions(+)

FYI, this is now the 4th copy of this operation.

  arm: pmull
  x86: pclmulqdq
  ppc: vpmsum[bhwd]

We really should promote this to generic.  But that can come later,

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~