From: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
To: Kristoffer Haugsbakk <kristofferhaugsbakk@fastmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH v2 5/6] bswap.h: Remove optimized x86 version of bswap32/64
Date: Tue, 15 Jul 2025 21:02:29 +0200 [thread overview]
Message-ID: <20250715190229.ed-A7kgh@breakpoint.cc> (raw)
In-Reply-To: <e00dff7e-1920-45b6-85d2-49e6a1218882@app.fastmail.com>
On 2025-06-26 17:55:43 [+0200], Kristoffer Haugsbakk wrote:
> On Thu, Jun 12, 2025, at 00:14, Sebastian Andrzej Siewior wrote:
> > On x86 the bswap32/64 macro is implemenated based on the x86 opcode wich
>
> s/implemenated/implemented/
>
> s/wich/which/
>
> > performs the required shifting in just one opcode.
> > The other CPUs fallback to the generic shifting as implemented by
> > default_swab32() and default_bswap64() if needed.
> >
> > I've been looking at how good a compiler is at recognizing the default
> > shift and emitting an optimized operation:
> > - x86, arm64 msvc v19.20
> > default_swab32() optimized
> > default_bswap64() shifts
> > _byteswap_uint64() otimized
> >
> > - x86, arm64 msvc v19.37
> > default_swab32() optimized
> > default_bswap64() optimized
> > _byteswap_uint64() otimized
>
> Is it supposed to say `otimized` twice?
Nope. Fixed. Thank you.
Sebastian
next prev parent reply other threads:[~2025-07-15 19:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-11 22:14 [PATCH v2 0/6] bswap.h: Rework ntohl handling Sebastian Andrzej Siewior
2025-06-11 22:14 ` [PATCH v2 1/6] Revert "bswap.h: add support for built-in bswap functions" Sebastian Andrzej Siewior
2025-06-12 20:04 ` Junio C Hamano
2025-06-11 22:14 ` [PATCH v2 2/6] bswap.h: Add support for __BYTE_ORDER__ Sebastian Andrzej Siewior
2025-06-12 0:24 ` brian m. carlson
2025-06-12 0:43 ` Collin Funk
2025-06-12 20:10 ` Junio C Hamano
2025-06-11 22:14 ` [PATCH v2 3/6] bswap.h: Define GIT_LITTLE_ENDIAN on msvc as little endian Sebastian Andrzej Siewior
2025-06-12 20:11 ` Junio C Hamano
2025-06-11 22:14 ` [PATCH v2 4/6] bswap.h: Always overwrite ntohl/ ntohll macros Sebastian Andrzej Siewior
2025-06-12 0:14 ` brian m. carlson
2025-06-12 20:16 ` Junio C Hamano
2025-06-11 22:14 ` [PATCH v2 5/6] bswap.h: Remove optimized x86 version of bswap32/64 Sebastian Andrzej Siewior
2025-06-26 15:55 ` Kristoffer Haugsbakk
2025-07-15 19:02 ` Sebastian Andrzej Siewior [this message]
2025-06-11 22:14 ` [PATCH v2 5/6] bswap: " Sebastian Andrzej Siewior
2025-06-11 22:14 ` [PATCH v2 6/6] bswap.h: Provide a built-in based version of bswap32/64 if possible Sebastian Andrzej Siewior
2025-06-12 20:21 ` [PATCH v2 0/6] bswap.h: Rework ntohl handling Junio C Hamano
2025-07-07 22:43 ` Junio C Hamano
2025-07-09 6:04 ` Sebastian Andrzej Siewior
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