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From: Peter Tyser <ptyser@xes-inc.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH V2 1/3] memcpy: copy one word at a time if possible
Date: Thu, 08 Oct 2009 11:30:56 -0500	[thread overview]
Message-ID: <1255019456.9100.1140.camel@localhost.localdomain> (raw)
In-Reply-To: <20091008160026.GA9077@mail.gnudd.com>

On Thu, 2009-10-08 at 18:00 +0200, Alessandro Rubini wrote:
> > No interest in the suggestion to not require count to be an exact
> > multiple of 4/8?
> 
> Actually, I wrote about that in my patch 0/3.

Sorry, I should have read more thoroughly.

> > I don't think it would be that hard to update the logic accordingly
> > and this would let your code be utilized much more often, especially
> > if/when we run on a 64-bit machine.
> 
> That's true, but I think the most important case is lcd scrolling,
> where it's usually a big power of two -- that's where we had the #ifdef,
> so the problem was known, I suppose.

I think the most important case for *you* is lcd scrolling, but for 99%
of everyone else, it isn't at all:)  memcpy() and memset() are used 100
times more often in non-lcd related code and most boards don't even have
LCDs.  In my opinion, we shouldn't be fixing/bloating common code for 1
outlying scenario, we should be trying to improve it for common cases.

> Currently, I don't even know if this is going to be picked up, so I
> don't want to go too far -- and in that case I would like to measure
> things and be able to test for stupid bugs, so it takes time.

Sure, I understand where you're coming from.  FWIW, if people don't want
to pick this up as it affects lots of people, you could always add an
architecture-specific memcpy/memset implementation.

> If there's interest, there's memmov to fix; it's used pretty often and
> it's the same idea as memcpy (well, scrolling should use memmove,
> in theory).

I'll quit pestering, just wanted to put my $.02 in:)

Best,
Peter

  reply	other threads:[~2009-10-08 16:30 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-08 11:29 [U-Boot] [PATCH V2 0/3] make memcpy and memset faster Alessandro Rubini
2009-10-08 11:30 ` [U-Boot] [PATCH V2 1/3] memcpy: copy one word at a time if possible Alessandro Rubini
2009-10-08 15:12   ` Peter Tyser
2009-10-08 16:00     ` Alessandro Rubini
2009-10-08 16:30       ` Peter Tyser [this message]
2009-10-08 18:23         ` Alessandro Rubini
2009-10-08 19:09           ` Peter Tyser
2009-10-08 19:17             ` Alessandro Rubini
2009-10-08 20:40               ` Wolfgang Denk
2009-10-08 20:47       ` Wolfgang Denk
2009-10-08 19:14   ` Mike Frysinger
2009-10-08 20:44   ` Wolfgang Denk
2009-10-09  4:42     ` Chris Moore
2009-10-09 10:11       ` Mark Jackson
2009-10-09 10:26         ` Mike Frysinger
2009-10-11  7:06           ` Chris Moore
2009-10-09 11:12       ` Wolfgang Denk
2009-10-08 11:30 ` [U-Boot] [PATCH V2 2/3] memset: fill " Alessandro Rubini
2009-10-08 20:46   ` Wolfgang Denk
2009-10-08 11:30 ` [U-Boot] [PATCH V2 3/3] lcd: remove '#if 0' 32-bit scroll, now memcpy does it Alessandro Rubini
2009-11-22 22:34   ` Wolfgang Denk
2009-11-24 23:04     ` Anatolij Gustschin
2009-10-08 20:36 ` [U-Boot] [PATCH V2 0/3] make memcpy and memset faster Wolfgang Denk
2009-10-08 21:30 ` Mike Frysinger

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