Add Arm NEON implementation of RGB->Grayscale
Adds an Arm NEON implementation of RGB -> Grayscale conversion. This
is new code written using compiler intrinsics; there was no previous
NEON assembly code implementation for either AArch32 or AArch64.
Bug: 922430
Change-Id: I1ce566c1741bcd15dca97a75571380d4c09c0572
diff --git a/BUILD.gn b/BUILD.gn
index b3b6470..901956a 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -156,6 +156,7 @@
"simd/arm/arm/jsimd.c",
"simd/arm/arm/jsimd_neon.S",
"simd/arm/common/jccolor-neon.c",
+ "simd/arm/common/jcgray-neon.c",
"simd/arm/common/jcsample-neon.c",
"simd/arm/common/jdcolor-neon.c",
"simd/arm/common/jdmerge-neon.c",
@@ -171,6 +172,7 @@
"simd/arm/arm64/jsimd.c",
"simd/arm/arm64/jsimd_neon.S",
"simd/arm/common/jccolor-neon.c",
+ "simd/arm/common/jcgray-neon.c",
"simd/arm/common/jcsample-neon.c",
"simd/arm/common/jdcolor-neon.c",
"simd/arm/common/jdmerge-neon.c",
diff --git a/README.chromium b/README.chromium
index fa4d87b..5e1b166 100644
--- a/README.chromium
+++ b/README.chromium
@@ -74,6 +74,7 @@
- Add Arm NEON implementation of h2v1_downsample
- Add Arm NEON implementation of h2v2_downsample
- Implement RGB->YCbCr using Arm NEON intrinsics
+ - Add Arm NEON implementation of RGB->Grayscale
* Patches to enable running the upstream unit tests through gtest.
The upstream unit tests are defined here under the section 'TESTS':
https://github.com/libjpeg-turbo/libjpeg-turbo/blob/master/CMakeLists.txt
diff --git a/simd/arm/arm/jsimd.c b/simd/arm/arm/jsimd.c
index 0ae1b57..98907a5 100644
--- a/simd/arm/arm/jsimd.c
+++ b/simd/arm/arm/jsimd.c
@@ -164,6 +164,19 @@
GLOBAL(int)
jsimd_can_rgb_gray(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 ((RGB_PIXELSIZE != 3) && (RGB_PIXELSIZE != 4))
+ return 0;
+
+ if (simd_support & JSIMD_NEON)
+ return 1;
+
return 0;
}
@@ -246,6 +259,37 @@
JSAMPIMAGE output_buf, JDIMENSION output_row,
int num_rows)
{
+ void (*neonfct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
+
+ switch (cinfo->in_color_space) {
+ case JCS_EXT_RGB:
+ neonfct = jsimd_extrgb_gray_convert_neon;
+ break;
+ case JCS_EXT_RGBX:
+ case JCS_EXT_RGBA:
+ neonfct = jsimd_extrgbx_gray_convert_neon;
+ break;
+ case JCS_EXT_BGR:
+ neonfct = jsimd_extbgr_gray_convert_neon;
+ break;
+ case JCS_EXT_BGRX:
+ case JCS_EXT_BGRA:
+ neonfct = jsimd_extbgrx_gray_convert_neon;
+ break;
+ case JCS_EXT_XBGR:
+ case JCS_EXT_ABGR:
+ neonfct = jsimd_extxbgr_gray_convert_neon;
+ break;
+ case JCS_EXT_XRGB:
+ case JCS_EXT_ARGB:
+ neonfct = jsimd_extxrgb_gray_convert_neon;
+ break;
+ default:
+ neonfct = jsimd_extrgb_gray_convert_neon;
+ break;
+ }
+
+ neonfct(cinfo->image_width, input_buf, output_buf, output_row, num_rows);
}
GLOBAL(void)
diff --git a/simd/arm/arm64/jsimd.c b/simd/arm/arm64/jsimd.c
index 8cc8f69..ca29cd6 100644
--- a/simd/arm/arm64/jsimd.c
+++ b/simd/arm/arm64/jsimd.c
@@ -176,6 +176,19 @@
GLOBAL(int)
jsimd_can_rgb_gray(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 ((RGB_PIXELSIZE != 3) && (RGB_PIXELSIZE != 4))
+ return 0;
+
+ if (simd_support & JSIMD_NEON)
+ return 1;
+
return 0;
}
@@ -258,6 +271,37 @@
JSAMPIMAGE output_buf, JDIMENSION output_row,
int num_rows)
{
+ void (*neonfct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
+
+ switch (cinfo->in_color_space) {
+ case JCS_EXT_RGB:
+ neonfct = jsimd_extrgb_gray_convert_neon;
+ break;
+ case JCS_EXT_RGBX:
+ case JCS_EXT_RGBA:
+ neonfct = jsimd_extrgbx_gray_convert_neon;
+ break;
+ case JCS_EXT_BGR:
+ neonfct = jsimd_extbgr_gray_convert_neon;
+ break;
+ case JCS_EXT_BGRX:
+ case JCS_EXT_BGRA:
+ neonfct = jsimd_extbgrx_gray_convert_neon;
+ break;
+ case JCS_EXT_XBGR:
+ case JCS_EXT_ABGR:
+ neonfct = jsimd_extxbgr_gray_convert_neon;
+ break;
+ case JCS_EXT_XRGB:
+ case JCS_EXT_ARGB:
+ neonfct = jsimd_extxrgb_gray_convert_neon;
+ break;
+ default:
+ neonfct = jsimd_extrgb_gray_convert_neon;
+ break;
+ }
+
+ neonfct(cinfo->image_width, input_buf, output_buf, output_row, num_rows);
}
GLOBAL(void)
diff --git a/simd/arm/common/jcgray-neon.c b/simd/arm/common/jcgray-neon.c
new file mode 100644
index 0000000..4cba0ef
--- /dev/null
+++ b/simd/arm/common/jcgray-neon.c
@@ -0,0 +1,117 @@
+/*
+ * jcgray-neon.c - grayscale colorspace conversion (Arm NEON)
+ *
+ * Copyright 2020 The Chromium Authors. All Rights Reserved.
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+#define JPEG_INTERNALS
+#include "../../../jinclude.h"
+#include "../../../jpeglib.h"
+#include "../../../jsimd.h"
+#include "../../../jdct.h"
+#include "../../../jsimddct.h"
+#include "../../jsimd.h"
+
+#include <arm_neon.h>
+
+/* RGB -> Grayscale conversion constants. */
+
+#define F_0_298 19595
+#define F_0_587 38470
+#define F_0_113 7471
+
+/* Include inline routines for colorspace extensions. */
+
+#include "jcgryext-neon.c"
+#undef RGB_RED
+#undef RGB_GREEN
+#undef RGB_BLUE
+#undef RGB_PIXELSIZE
+
+#define RGB_RED EXT_RGB_RED
+#define RGB_GREEN EXT_RGB_GREEN
+#define RGB_BLUE EXT_RGB_BLUE
+#define RGB_PIXELSIZE EXT_RGB_PIXELSIZE
+#define jsimd_rgb_gray_convert_neon jsimd_extrgb_gray_convert_neon
+#include "jcgryext-neon.c"
+#undef RGB_RED
+#undef RGB_GREEN
+#undef RGB_BLUE
+#undef RGB_PIXELSIZE
+#undef jsimd_rgb_gray_convert_neon
+
+#define RGB_RED EXT_RGBX_RED
+#define RGB_GREEN EXT_RGBX_GREEN
+#define RGB_BLUE EXT_RGBX_BLUE
+#define RGB_PIXELSIZE EXT_RGBX_PIXELSIZE
+#define jsimd_rgb_gray_convert_neon jsimd_extrgbx_gray_convert_neon
+#include "jcgryext-neon.c"
+#undef RGB_RED
+#undef RGB_GREEN
+#undef RGB_BLUE
+#undef RGB_PIXELSIZE
+#undef jsimd_rgb_gray_convert_neon
+
+#define RGB_RED EXT_BGR_RED
+#define RGB_GREEN EXT_BGR_GREEN
+#define RGB_BLUE EXT_BGR_BLUE
+#define RGB_PIXELSIZE EXT_BGR_PIXELSIZE
+#define jsimd_rgb_gray_convert_neon jsimd_extbgr_gray_convert_neon
+#include "jcgryext-neon.c"
+#undef RGB_RED
+#undef RGB_GREEN
+#undef RGB_BLUE
+#undef RGB_PIXELSIZE
+#undef jsimd_rgb_gray_convert_neon
+
+#define RGB_RED EXT_BGRX_RED
+#define RGB_GREEN EXT_BGRX_GREEN
+#define RGB_BLUE EXT_BGRX_BLUE
+#define RGB_PIXELSIZE EXT_BGRX_PIXELSIZE
+#define jsimd_rgb_gray_convert_neon jsimd_extbgrx_gray_convert_neon
+#include "jcgryext-neon.c"
+#undef RGB_RED
+#undef RGB_GREEN
+#undef RGB_BLUE
+#undef RGB_PIXELSIZE
+#undef jsimd_rgb_gray_convert_neon
+
+#define RGB_RED EXT_XBGR_RED
+#define RGB_GREEN EXT_XBGR_GREEN
+#define RGB_BLUE EXT_XBGR_BLUE
+#define RGB_PIXELSIZE EXT_XBGR_PIXELSIZE
+#define jsimd_rgb_gray_convert_neon jsimd_extxbgr_gray_convert_neon
+#include "jcgryext-neon.c"
+#undef RGB_RED
+#undef RGB_GREEN
+#undef RGB_BLUE
+#undef RGB_PIXELSIZE
+#undef jsimd_rgb_gray_convert_neon
+
+#define RGB_RED EXT_XRGB_RED
+#define RGB_GREEN EXT_XRGB_GREEN
+#define RGB_BLUE EXT_XRGB_BLUE
+#define RGB_PIXELSIZE EXT_XRGB_PIXELSIZE
+#define jsimd_rgb_gray_convert_neon jsimd_extxrgb_gray_convert_neon
+#include "jcgryext-neon.c"
+#undef RGB_RED
+#undef RGB_GREEN
+#undef RGB_BLUE
+#undef RGB_PIXELSIZE
+#undef jsimd_rgb_gray_convert_neon
diff --git a/simd/arm/common/jcgryext-neon.c b/simd/arm/common/jcgryext-neon.c
new file mode 100644
index 0000000..35ba0ac
--- /dev/null
+++ b/simd/arm/common/jcgryext-neon.c
@@ -0,0 +1,107 @@
+/*
+ * jcgryext-neon.c - grayscale colorspace conversion (Arm NEON)
+ *
+ * Copyright 2020 The Chromium Authors. All Rights Reserved.
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+/* This file is included by jcgray-neon.c */
+
+/*
+ * RGB -> Grayscale conversion is defined by the following equation:
+ * Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
+ *
+ * Avoid floating point arithmetic by using shifted integer constants:
+ * 0.29899597 = 19595 * 2^-16
+ * 0.58700561 = 38470 * 2^-16
+ * 0.11399841 = 7471 * 2^-16
+ * These constants are defined in jcgray-neon.c
+ *
+ * We use rounding later to get correct values.
+ *
+ * This is the same computation as the RGB -> Y portion of RGB -> YCbCr.
+ */
+
+void jsimd_rgb_gray_convert_neon(JDIMENSION image_width,
+ JSAMPARRAY input_buf,
+ JSAMPIMAGE output_buf,
+ JDIMENSION output_row,
+ int num_rows)
+{
+ JSAMPROW inptr;
+ JSAMPROW outptr;
+
+ while (--num_rows >= 0) {
+ inptr = *input_buf++;
+ outptr = output_buf[0][output_row];
+ output_row++;
+
+ int cols_remaining = image_width;
+ for (; cols_remaining > 0; cols_remaining -= 16) {
+
+ /* To prevent buffer overread by the vector load instructions, the */
+ /* last (image_width % 16) columns of data are first memcopied to a */
+ /* temporary buffer large enough to accommodate the vector load. */
+ if (cols_remaining < 16) {
+ uint8_t __attribute__((aligned(8))) tmp_buf[16 * RGB_PIXELSIZE];
+ memcpy(tmp_buf, inptr, cols_remaining * RGB_PIXELSIZE);
+ inptr = tmp_buf;
+ }
+
+#if RGB_PIXELSIZE == 4
+ uint8x16x4_t input_pixels = vld4q_u8(inptr);
+#else
+ uint8x16x3_t input_pixels = vld3q_u8(inptr);
+#endif
+ uint16x8_t r_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_RED]));
+ uint16x8_t r_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_RED]));
+ uint16x8_t g_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_GREEN]));
+ uint16x8_t g_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_GREEN]));
+ uint16x8_t b_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_BLUE]));
+ uint16x8_t b_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_BLUE]));
+
+ /* Compute Y = 0.29900 * R + 0.58700 * G + 0.11400 * B */
+ uint32x4_t y_ll = vmull_n_u16(vget_low_u16(r_l), F_0_298);
+ uint32x4_t y_lh = vmull_n_u16(vget_high_u16(r_l), F_0_298);
+ uint32x4_t y_hl = vmull_n_u16(vget_low_u16(r_h), F_0_298);
+ uint32x4_t y_hh = vmull_n_u16(vget_high_u16(r_h), F_0_298);
+ y_ll = vmlal_n_u16(y_ll, vget_low_u16(g_l), F_0_587);
+ y_lh = vmlal_n_u16(y_lh, vget_high_u16(g_l), F_0_587);
+ y_hl = vmlal_n_u16(y_hl, vget_low_u16(g_h), F_0_587);
+ y_hh = vmlal_n_u16(y_hh, vget_high_u16(g_h), F_0_587);
+ y_ll = vmlal_n_u16(y_ll, vget_low_u16(b_l), F_0_113);
+ y_lh = vmlal_n_u16(y_lh, vget_high_u16(b_l), F_0_113);
+ y_hl = vmlal_n_u16(y_hl, vget_low_u16(b_h), F_0_113);
+ y_hh = vmlal_n_u16(y_hh, vget_high_u16(b_h), F_0_113);
+
+ /* Descale Y values (rounding right shift) and narrow to 16-bit. */
+ uint16x8_t y_l = vcombine_u16(vrshrn_n_u32(y_ll, 16),
+ vrshrn_n_u32(y_lh, 16));
+ uint16x8_t y_h = vcombine_u16(vrshrn_n_u32(y_hl, 16),
+ vrshrn_n_u32(y_hh, 16));
+
+ /* Narrow Y values to 8-bit and store to memory. Buffer overwrite is */
+ /* permitted up to the next multiple of ALIGN_SIZE bytes. */
+ vst1q_u8(outptr, vcombine_u8(vmovn_u16(y_l), vmovn_u16(y_h)));
+
+ /* Increment pointers. */
+ inptr += (16 * RGB_PIXELSIZE);
+ outptr += 16;
+ }
+ }
+}
diff --git a/simd/jsimd.h b/simd/jsimd.h
index 50a3c5d..99c8801 100644
--- a/simd/jsimd.h
+++ b/simd/jsimd.h
@@ -256,6 +256,28 @@
(JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_rgb_gray_convert_neon
+ (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extrgb_gray_convert_neon
+ (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extrgbx_gray_convert_neon
+ (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extbgr_gray_convert_neon
+ (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extbgrx_gray_convert_neon
+ (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extxbgr_gray_convert_neon
+ (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extxrgb_gray_convert_neon
+ (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+ JDIMENSION output_row, int num_rows);
+
EXTERN(void) jsimd_rgb_gray_convert_dspr2
(JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
JDIMENSION output_row, int num_rows);
