Fw: [PATCH][AArch64] Optimized memcpy/memmove

[Wilco Dijkstra]

ping

________________________________________
From: Wilco Dijkstra
Sent: 12 May 2016 17:25
To: Marcus Shawcroft
Cc: GNU C Library; nd
Subject: Re: [PATCH][AArch64] Optimized memcpy/memmove

Marcus Shawcroft wrote:
> Hi, There appear to be odd tab characters inserted throughout the
> comments,  for example:

Hmm, it appears unexpand is buggy, so you end up having to do tabs
all by hand... Attached updated version.

Wilco

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This is an optimized memcpy/memmove for AArch64. Copies are split into 3 main cases: small copies of up to 16 bytes, medium copies of 17..96 bytes which are fully unrolled. Large copies of more than 96 bytes align the destination and use an unrolled loop processing 64 bytes per iteration. In order to share code with memmove, small and medium copies read all data before writing, allowing any kind of overlap. All memmoves except for the large backwards case fall into memcpy for optimal performance. On a random copy test memcpy/memmove are 40.8% faster on A57 and 28.4% on A53.

ChangeLog:
2015-07-08  Wilco Dijkstra  <wdijkstr@arm.com>

        * sysdeps/aarch64/memcpy.S (memcpy):
        Rewrite of optimized memcpy and memmove.
        * sysdeps/aarch64/memmove.S (memmove): Remove
        memmove code (merged into memcpy.S).

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