linux-kernel - Re: [PATCH] Documentation about unaligned memory access

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Date:	Wed, 5 Dec 2007 21:07:34 -0800
From:	Brandon Philips <brandon@...p.org>
To:	Daniel Drake <dsd@...too.org>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Documentation about unaligned memory access

On 16:11 Mon 03 Dec 2007, Daniel Drake wrote:
> Here's a document I wrote after figuring out what unaligned memory access
> is all about. I've tried to cover the information I was looking for when
> trying to learn about this, without producing a hopelessly detailed/complex
> spew. I hope it is useful to others.
> 
> Signed-off-by: Daniel Drake <dsd@...too.org>
> 
> ---
<snip>
> +These macros work work for memory accesses of any length (not just 32 bits as

Remove a "work" here.

> +in the examples above). Be aware that when compared to standard access of
> +aligned memory, using these macros to access unaligned memory can be costly in
> +terms of performance.
> +
> +If use of such macros is not convenient, another option is to use memcpy(),
> +where the source or destination (or both) are of type u8* or unsigned char*.
> +Due to the byte-wise nature of this operation, unaligned accesses are avoided.

Cheers,

	Brandon
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