Neon: Intrinsics impl. of h2v1 & h2v2 plain upsamp
There was no previous GAS implementation.
NOTE: This doesn't produce much of a speedup when using -O3, because -O3
already enables Neon autovectorization, which works well for the scalar
C implementation of plain upsampling. However, the Neon SIMD
implementation will benefit other optimization levels.
diff --git a/simd/arm/aarch32/jsimd.c b/simd/arm/aarch32/jsimd.c
index df13c11..fac55df 100644
--- a/simd/arm/aarch32/jsimd.c
+++ b/simd/arm/aarch32/jsimd.c
@@ -399,12 +399,33 @@
GLOBAL(int)
jsimd_can_h2v2_upsample(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_NEON)
+ return 1;
+
return 0;
}
GLOBAL(int)
jsimd_can_h2v1_upsample(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_NEON)
+ return 1;
+
return 0;
}
@@ -412,12 +433,16 @@
jsimd_h2v2_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
{
+ jsimd_h2v2_upsample_neon(cinfo->max_v_samp_factor, cinfo->output_width,
+ input_data, output_data_ptr);
}
GLOBAL(void)
jsimd_h2v1_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
{
+ jsimd_h2v1_upsample_neon(cinfo->max_v_samp_factor, cinfo->output_width,
+ input_data, output_data_ptr);
}
GLOBAL(int)
diff --git a/simd/arm/aarch64/jsimd.c b/simd/arm/aarch64/jsimd.c
index 74cd6cc..8570b82 100644
--- a/simd/arm/aarch64/jsimd.c
+++ b/simd/arm/aarch64/jsimd.c
@@ -467,12 +467,33 @@
GLOBAL(int)
jsimd_can_h2v2_upsample(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_NEON)
+ return 1;
+
return 0;
}
GLOBAL(int)
jsimd_can_h2v1_upsample(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_NEON)
+ return 1;
+
return 0;
}
@@ -480,12 +501,16 @@
jsimd_h2v2_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
{
+ jsimd_h2v2_upsample_neon(cinfo->max_v_samp_factor, cinfo->output_width,
+ input_data, output_data_ptr);
}
GLOBAL(void)
jsimd_h2v1_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
{
+ jsimd_h2v1_upsample_neon(cinfo->max_v_samp_factor, cinfo->output_width,
+ input_data, output_data_ptr);
}
GLOBAL(int)
diff --git a/simd/arm/jdsample-neon.c b/simd/arm/jdsample-neon.c
index b31d6cf..90ec678 100644
--- a/simd/arm/jdsample-neon.c
+++ b/simd/arm/jdsample-neon.c
@@ -465,3 +465,105 @@
}
}
}
+
+
+/* The diagram below shows a row of samples produced by h2v1 downsampling.
+ *
+ * s0 s1
+ * +---------+---------+
+ * | | |
+ * | p0 p1 | p2 p3 |
+ * | | |
+ * +---------+---------+
+ *
+ * Samples s0 and s1 were created by averaging the original pixel component
+ * values centered at positions p0-p3 above. To approximate those original
+ * pixel component values, we duplicate the samples horizontally:
+ * p0(upsampled) = p1(upsampled) = s0
+ * p2(upsampled) = p3(upsampled) = s1
+ */
+
+void jsimd_h2v1_upsample_neon(int max_v_samp_factor, JDIMENSION output_width,
+ JSAMPARRAY input_data,
+ JSAMPARRAY *output_data_ptr)
+{
+ JSAMPARRAY output_data = *output_data_ptr;
+ JSAMPROW inptr, outptr;
+ int inrow;
+ unsigned colctr;
+
+ for (inrow = 0; inrow < max_v_samp_factor; inrow++) {
+ inptr = input_data[inrow];
+ outptr = output_data[inrow];
+ for (colctr = 0; 2 * colctr < output_width; colctr += 16) {
+ uint8x16_t samples = vld1q_u8(inptr + colctr);
+ /* Duplicate the samples. The store operation below interleaves them so
+ * that adjacent pixel component values take on the same sample value,
+ * per above.
+ */
+ uint8x16x2_t output_pixels = { { samples, samples } };
+ /* Store pixel component values to memory.
+ * Due to the way sample buffers are allocated, we don't need to worry
+ * about tail cases when output_width is not a multiple of 32. See
+ * "Creation of 2-D sample arrays" in jmemmgr.c for details.
+ */
+ vst2q_u8(outptr + 2 * colctr, output_pixels);
+ }
+ }
+}
+
+
+/* The diagram below shows an array of samples produced by h2v2 downsampling.
+ *
+ * s0 s1
+ * +---------+---------+
+ * | p0 p1 | p2 p3 |
+ * sA | | |
+ * | p4 p5 | p6 p7 |
+ * +---------+---------+
+ * | p8 p9 | p10 p11|
+ * sB | | |
+ * | p12 p13| p14 p15|
+ * +---------+---------+
+ *
+ * Samples s0A-s1B were created by averaging the original pixel component
+ * values centered at positions p0-p15 above. To approximate those original
+ * pixel component values, we duplicate the samples both horizontally and
+ * vertically:
+ * p0(upsampled) = p1(upsampled) = p4(upsampled) = p5(upsampled) = s0A
+ * p2(upsampled) = p3(upsampled) = p6(upsampled) = p7(upsampled) = s1A
+ * p8(upsampled) = p9(upsampled) = p12(upsampled) = p13(upsampled) = s0B
+ * p10(upsampled) = p11(upsampled) = p14(upsampled) = p15(upsampled) = s1B
+ */
+
+void jsimd_h2v2_upsample_neon(int max_v_samp_factor, JDIMENSION output_width,
+ JSAMPARRAY input_data,
+ JSAMPARRAY *output_data_ptr)
+{
+ JSAMPARRAY output_data = *output_data_ptr;
+ JSAMPROW inptr, outptr0, outptr1;
+ int inrow, outrow;
+ unsigned colctr;
+
+ for (inrow = 0, outrow = 0; outrow < max_v_samp_factor; inrow++) {
+ inptr = input_data[inrow];
+ outptr0 = output_data[outrow++];
+ outptr1 = output_data[outrow++];
+
+ for (colctr = 0; 2 * colctr < output_width; colctr += 16) {
+ uint8x16_t samples = vld1q_u8(inptr + colctr);
+ /* Duplicate the samples. The store operation below interleaves them so
+ * that adjacent pixel component values take on the same sample value,
+ * per above.
+ */
+ uint8x16x2_t output_pixels = { { samples, samples } };
+ /* Store pixel component values for both output rows to memory.
+ * Due to the way sample buffers are allocated, we don't need to worry
+ * about tail cases when output_width is not a multiple of 32. See
+ * "Creation of 2-D sample arrays" in jmemmgr.c for details.
+ */
+ vst2q_u8(outptr0 + 2 * colctr, output_pixels);
+ vst2q_u8(outptr1 + 2 * colctr, output_pixels);
+ }
+ }
+}
diff --git a/simd/jsimd.h b/simd/jsimd.h
index ccc9a10..64747c6 100644
--- a/simd/jsimd.h
+++ b/simd/jsimd.h
@@ -615,6 +615,13 @@
(int max_v_samp_factor, JDIMENSION output_width, JSAMPARRAY input_data,
JSAMPARRAY *output_data_ptr);
+EXTERN(void) jsimd_h2v1_upsample_neon
+ (int max_v_samp_factor, JDIMENSION output_width, JSAMPARRAY input_data,
+ JSAMPARRAY *output_data_ptr);
+EXTERN(void) jsimd_h2v2_upsample_neon
+ (int max_v_samp_factor, JDIMENSION output_width, JSAMPARRAY input_data,
+ JSAMPARRAY *output_data_ptr);
+
EXTERN(void) jsimd_h2v1_upsample_dspr2
(int max_v_samp_factor, JDIMENSION output_width, JSAMPARRAY input_data,
JSAMPARRAY *output_data_ptr);
