From: David Laight <David.Laight@ACULAB.COM>
To: "'Marius.Cristea@microchip.com'" <Marius.Cristea@microchip.com>,
"arnd@arndb.de" <arnd@arndb.de>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v1] asm-generic: introduce be56 unaligned accessors
Date: Tue, 8 Oct 2024 09:03:27 +0000 [thread overview]
Message-ID: <8280ddecc4e14643b446c018d89fab28@AcuMS.aculab.com> (raw)
In-Reply-To: <2f53046dd5b791845c2ffa783d7637ca94ca330c.camel@microchip.com>
...
> I'm using block read in order to get multiple registers at a time
> (around 76 bytes) and to increase the efficiency of the transfer over
> I2C. Being a block read there are different registers length involved
> from 16 up to 56 bits long and I need to unpack.
You could do an unaligned 64bit BE read and then shift the value right 8 bits
(and only advance the pointer 7 bytes).
Safe because you can guarantee a spare byte at the end of the data.
On x86-64 you could do that for all sizes!
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2024-10-08 9:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-27 8:35 [PATCH v1] asm-generic: introduce be56 unaligned accessors marius.cristea
2024-09-29 21:16 ` David Laight
2024-10-07 14:40 ` Marius.Cristea
2024-10-07 14:44 ` Arnd Bergmann
2024-10-07 14:57 ` Marius.Cristea
2024-10-07 17:08 ` Arnd Bergmann
2024-10-08 9:03 ` David Laight [this message]
2024-10-07 15:05 ` David Laight
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