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+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1385 632fc199-4ca6-4c93-a231-07263d6284db
diff --git a/simd/jsimd_arm.c b/simd/jsimd_arm.c
index aefb1e6..4cbcf2d 100644
--- a/simd/jsimd_arm.c
+++ b/simd/jsimd_arm.c
@@ -2,7 +2,7 @@
* jsimd_arm.c
*
* Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright 2009-2011, 2013 D. R. Commander
+ * Copyright 2009-2011, 2013-2014 D. R. Commander
*
* Based on the x86 SIMD extension for IJG JPEG library,
* Copyright (C) 1999-2006, MIYASAKA Masaru.
@@ -175,6 +175,23 @@
return 0;
}
+GLOBAL(int)
+jsimd_can_ycc_rgb565 (void)
+{
+ init_simd();
+
+ /* The code is optimised for these values only */
+ if (BITS_IN_JSAMPLE != 8)
+ return 0;
+ if (sizeof(JDIMENSION) != 4)
+ return 0;
+
+ if (simd_support & JSIMD_ARM_NEON)
+ return 1;
+
+ return 0;
+}
+
GLOBAL(void)
jsimd_rgb_ycc_convert (j_compress_ptr cinfo,
JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
@@ -251,7 +268,7 @@
case JCS_EXT_ARGB:
neonfct=jsimd_ycc_extxrgb_convert_neon;
break;
- default:
+ default:
neonfct=jsimd_ycc_extrgb_convert_neon;
break;
}
@@ -260,6 +277,16 @@
neonfct(cinfo->output_width, input_buf, input_row, output_buf, num_rows);
}
+GLOBAL(void)
+jsimd_ycc_rgb565_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ if (simd_support & JSIMD_ARM_NEON)
+ jsimd_ycc_rgb565_convert_neon(cinfo->output_width, input_buf, input_row,
+ output_buf, num_rows);
+}
+
GLOBAL(int)
jsimd_can_h2v2_downsample (void)
{