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From: Alessandro Rubini <rubini-list@gnudd.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH V2 0/3] make memcpy and memset faster
Date: Thu, 8 Oct 2009 13:29:51 +0200	[thread overview]
Message-ID: <cover.1255000877.git.rubini@unipv.it> (raw)

I've added 32-bit lcd to the Nomadik (not submitted yet), and I found
the scroll to be very slow, as the screen is big.

Instead of activating the "if 0" stanza for 32-bit scroll in lcd.c,
I'd better have a faster memcpy/memset globally. So this patch set
adds ulong-wide memcpy and memset, then removes the "#if 0" part in the
scroll function. For me scrolling is 4 times faster on a 32 bit system.

V2: I incorporated most of the comments, but I didn't change the for
loops to help the compiler optimizing it, since nowadays gcc is
already doing the loops his own way irrespective of what i write.

Similarly, I'm not interested in "4 bytes at a time, then 1 at a time"
as it's quite a corner case. If such optimizations are really useful,
then we'd better have hand-crafted assembly for each arch, possibly
lifted from glibc.

Alessandro Rubini (3):
  memcpy: copy one word at a time if possible
  memset: fill one word at a time if possible
  lcd: remove '#if 0' 32-bit scroll, now memcpy does it

 common/lcd.c         |   21 ---------------------
 lib_generic/string.c |   34 +++++++++++++++++++++++++++++-----
 2 files changed, 29 insertions(+), 26 deletions(-)

             reply	other threads:[~2009-10-08 11:29 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-08 11:29 Alessandro Rubini [this message]
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
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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