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ARM NEON SIMD support for YCC-to-RGB565 conversion, and optimizations to the existing YCC-to-RGB conversion code:

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aee36252be.patch

From aee36252be20054afce371a92406fc66ba6627b5 Mon Sep 17 00:00:00 2001
From: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Date: Wed, 13 Aug 2014 03:50:22 +0300
Subject: [PATCH] ARM: Faster NEON yuv->rgb conversion for Krait and Cortex-A15

The older code was developed and tested only on ARM Cortex-A8 and ARM Cortex-A9.
Tuning it for newer ARM processors can introduce some speed-up (up to 20%).

The performance of the inner loop (conversion of 8 pixels) improves from
~27 cycles down to ~22 cycles on Qualcomm Krait 300, and from ~20 cycles
down to ~18 cycles on ARM Cortex-A15.

The performance remains exactly the same on ARM Cortex-A7 (~58 cycles),
ARM Cortex-A8 (~25 cycles) and ARM Cortex-A9 (~30 cycles) processors.

Also use larger indentation in the source code for separating two independent
instruction streams.

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a5efdbf22c.patch

From a5efdbf22ce9c1acd4b14a353cec863c2c57557e Mon Sep 17 00:00:00 2001
From: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Date: Wed, 13 Aug 2014 07:23:09 +0300
Subject: [PATCH] ARM: NEON optimized yuv->rgb565 conversion

The performance of the inner loop (conversion of 8 pixels):
* ARM Cortex-A7:  ~55 cycles
* ARM Cortex-A8:  ~28 cycles
* ARM Cortex-A9:  ~32 cycles
* ARM Cortex-A15: ~20 cycles
* Qualcomm Krait: ~24 cycles

Based on the Linaro rgb565 patch from
    https://sourceforge.net/p/libjpeg-turbo/patches/24/
but implements better instructions scheduling.


git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1385 632fc199-4ca6-4c93-a231-07263d6284db
This commit is contained in:
DRC
2014-08-23 15:47:51 +00:00
parent f5644c3498
commit d729f4da9c
11 changed files with 172 additions and 25 deletions
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10
jdcolor.c
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@@ -6,7 +6,7 @@
* Modified 2011 by Guido Vollbeding.
* libjpeg-turbo Modifications:
* Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
* Copyright (C) 2009, 2011-2012, D. R. Commander.
* Copyright (C) 2009, 2011-2012, 2014, D. R. Commander.
* Copyright (C) 2013, Linaro Limited.
* For conditions of distribution and use, see the accompanying README file.
*
@@ -657,8 +657,12 @@ jinit_color_deconverter (j_decompress_ptr cinfo)
cinfo->out_color_components = 3;
if (cinfo->dither_mode == JDITHER_NONE) {
if (cinfo->jpeg_color_space == JCS_YCbCr) {
cconvert->pub.color_convert = ycc_rgb565_convert;
build_ycc_rgb_table(cinfo);
if (jsimd_can_ycc_rgb565())
cconvert->pub.color_convert = jsimd_ycc_rgb565_convert;
else {
cconvert->pub.color_convert = ycc_rgb565_convert;
build_ycc_rgb_table(cinfo);
}
} else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) {
cconvert->pub.color_convert = gray_rgb565_convert;
} else if (cinfo->jpeg_color_space == JCS_RGB) {