[x265] [PATCH 0/2] Add Neon impl of findPosFirstLast

[Micro Daryl Robles]

Hi Chen,

Thank you for the approval.

Yes, EOR and ADD have the same instruction cost (latency / throughput / pipeline) in AArch64 across Neoverse (Nx, Vx), so using either should be optimal.

Regards,
Micro

From: chen <chenm003 at 163.com>
Date: Wednesday, 9 April 2025 at 07:10
To: Development for x265 <x265-devel at videolan.org>
Cc: nd <nd at arm.com>, Micro Daryl Robles <MicroDaryl.Robles at arm.com>
Subject: Re:[x265] [PATCH 0/2] Add Neon impl of findPosFirstLast

Hi Micro,



The code looks good to me, I have no more comment, thank you.



btw: for absSumSign, does EOR and ADD same instruction cost on Neoverse?



Regards,
Chen



At 2025-04-08 23:13:29, "Micro Daryl Robles" <microdaryl.robles at arm.com> wrote:

>Hi,

>

>This patch series adds a Neon intrinsic implementation of

>findPosFirstLast.

>

>Also, we are submitting a proposal to rename CLZ/CTZ to BSR/BSF, as the

>current CLZ macro does not actually count leading zeros. Instead, it

>returns the index of the highest set bit, which aligns with the behavior

>of BSR.

>

>This series is based on the master branch.

>

>Many thanks,

>Micro

>

>Micro Daryl Robles (2):

>  AArch64: Add Neon implementation of findPosFirstLast

>  Rename CLZ/CTZ to BSR/BSF

>

> source/common/aarch64/dct-prim.cpp  | 55 ++++++++++++++++++++++++++++-

> source/common/aarch64/dct-prim.h    |  2 +-

> source/common/bitstream.cpp         |  2 +-

> source/common/dct.cpp               |  4 +--

> source/common/ppc/dct_altivec.cpp   |  2 +-

> source/common/quant.cpp             |  8 ++---

> source/common/threading.h           | 18 ++++++----

> source/common/threadpool.cpp        | 10 +++---

> source/common/wavefront.cpp         |  2 +-

> source/common/x86/pixel-util8.asm   |  4 +--

> source/encoder/entropy.cpp          | 10 +++---

> source/encoder/frameencoder.cpp     |  4 +--

> source/encoder/slicetype.cpp        |  2 +-

> source/encoder/weightPrediction.cpp |  2 +-

> source/test/pixelharness.cpp        | 12 +++++--

> 15 files changed, 102 insertions(+), 35 deletions(-)

>

>--

>2.34.1

>

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