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

-----

https://github.com/ssvb/libjpeg-turbo/commit/aee36252be20054afce371a92406fc66ba6627b5.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.

-----

https://github.com/ssvb/libjpeg-turbo/commit/a5efdbf22ce9c1acd4b14a353cec863c2c57557e.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://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1385 632fc199-4ca6-4c93-a231-07263d6284db

1 files changed, 7 insertions, 3 deletions

diff --git a/jdcolor.c b/jdcolor.c
index 6927e5e..ffedabd 100644
--- a/jdcolor.c
+++ b/jdcolor.c
@@ -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) {