NEON implementation of some Sharp-YUV420 functions

Change-Id: I449ef9c76b06f971f6e2ad7f9db96bf906d8fe1f
new-file: dsp/yuv_neon.c

Android.mk

@@ -79,6 +79,7 @@ dsp_dec_srcs := \
     src/dsp/yuv.c \
     src/dsp/yuv_mips32.c \
     src/dsp/yuv_mips_dsp_r2.c \
+    src/dsp/yuv_neon.$(NEON) \
     src/dsp/yuv_sse2.c \
 
 dsp_enc_srcs := \

Makefile.vc

@@ -229,6 +229,7 @@ DSP_DEC_OBJS = \
     $(DIROBJ)\dsp\yuv.obj \
     $(DIROBJ)\dsp\yuv_mips32.obj \
     $(DIROBJ)\dsp\yuv_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\yuv_neon.obj \
     $(DIROBJ)\dsp\yuv_sse2.obj \
 
 DSP_ENC_OBJS = \

build.gradle

@@ -148,6 +148,7 @@ model {
             include "yuv.c"
             include "yuv_mips32.c"
             include "yuv_mips_dsp_r2.c"
+            include "yuv_neon.$NEON"
             include "yuv_sse2.c"
             srcDir "src/utils"
             include "bit_reader_utils.c"

makefile.unix

@@ -169,6 +169,7 @@ DSP_DEC_OBJS = \
     src/dsp/yuv.o \
     src/dsp/yuv_mips32.o \
     src/dsp/yuv_mips_dsp_r2.o \
+    src/dsp/yuv_neon.o \
     src/dsp/yuv_sse2.o \
 
 DSP_ENC_OBJS = \

src/dsp/Makefile.am

@@ -82,6 +82,7 @@ libwebpdspdecode_neon_la_SOURCES += lossless_neon.c
 libwebpdspdecode_neon_la_SOURCES += neon.h
 libwebpdspdecode_neon_la_SOURCES += rescaler_neon.c
 libwebpdspdecode_neon_la_SOURCES += upsampling_neon.c
+libwebpdspdecode_neon_la_SOURCES += yuv_neon.c
 libwebpdspdecode_neon_la_CPPFLAGS = $(libwebpdsp_neon_la_CPPFLAGS)
 libwebpdspdecode_neon_la_CFLAGS = $(libwebpdsp_neon_la_CFLAGS)
 

src/dsp/yuv.c

@@ -309,6 +309,7 @@ static volatile VP8CPUInfo rgba_to_yuv_last_cpuinfo_used =
 
 extern void WebPInitConvertARGBToYUVSSE2(void);
 extern void WebPInitSharpYUVSSE2(void);
+extern void WebPInitSharpYUVNEON(void);
 
 WEBP_TSAN_IGNORE_FUNCTION void WebPInitConvertARGBToYUV(void) {
   if (rgba_to_yuv_last_cpuinfo_used == VP8GetCPUInfo) return;
@@ -332,6 +333,12 @@ WEBP_TSAN_IGNORE_FUNCTION void WebPInitConvertARGBToYUV(void) {
       WebPInitSharpYUVSSE2();
     }
 #endif  // WEBP_USE_SSE2
+#if defined(WEBP_USE_NEON)
+    if (VP8GetCPUInfo(kNEON)) {
+      WebPInitSharpYUVNEON();
+    }
+#endif  // WEBP_USE_NEON
+
   }
   rgba_to_yuv_last_cpuinfo_used = VP8GetCPUInfo;
 }

src/dsp/yuv_neon.c

@@ -0,0 +1,136 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// YUV->RGB conversion functions
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "./yuv.h"
+
+#if defined(WEBP_USE_NEON)
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include "./neon.h"
+
+//-----------------------------------------------------------------------------
+
+#define MAX_Y ((1 << 10) - 1)    // 10b precision over 16b-arithmetic
+static uint16_t clip_y(int v) {
+  return (v < 0) ? 0 : (v > MAX_Y) ? MAX_Y : (uint16_t)v;
+}
+
+static uint64_t SharpYUVUpdateY_NEON(const uint16_t* ref, const uint16_t* src,
+                                     uint16_t* dst, int len) {
+  int i;
+  const int16x8_t zero = vdupq_n_s16(0);
+  const int16x8_t max = vdupq_n_s16(MAX_Y);
+  uint64x2_t sum = vdupq_n_u64(0);
+  uint64_t diff;
+
+  for (i = 0; i + 8 <= len; i += 8) {
+    const int16x8_t A = vreinterpretq_s16_u16(vld1q_u16(ref + i));
+    const int16x8_t B = vreinterpretq_s16_u16(vld1q_u16(src + i));
+    const int16x8_t C = vreinterpretq_s16_u16(vld1q_u16(dst + i));
+    const int16x8_t D = vsubq_s16(A, B);       // diff_y
+    const int16x8_t F = vaddq_s16(C, D);       // new_y
+    const uint16x8_t H =
+        vreinterpretq_u16_s16(vmaxq_s16(vminq_s16(F, max), zero));
+    const int16x8_t I = vabsq_s16(D);          // abs(diff_y)
+    vst1q_u16(dst + i, H);
+    sum = vpadalq_u32(sum, vpaddlq_u16(vreinterpretq_u16_s16(I)));
+  }
+  diff = vgetq_lane_u64(sum, 0) + vgetq_lane_u64(sum, 1);
+  for (; i < len; ++i) {
+    const int diff_y = ref[i] - src[i];
+    const int new_y = (int)(dst[i]) + diff_y;
+    dst[i] = clip_y(new_y);
+    diff += (uint64_t)(abs(diff_y));
+  }
+  return diff;
+}
+
+static void SharpYUVUpdateRGB_NEON(const int16_t* ref, const int16_t* src,
+                                   int16_t* dst, int len) {
+  int i;
+  for (i = 0; i + 8 <= len; i += 8) {
+    const int16x8_t A = vld1q_s16(ref + i);
+    const int16x8_t B = vld1q_s16(src + i);
+    const int16x8_t C = vld1q_s16(dst + i);
+    const int16x8_t D = vsubq_s16(A, B);   // diff_uv
+    const int16x8_t E = vaddq_s16(C, D);   // new_uv
+    vst1q_s16(dst + i, E);
+  }
+  for (; i < len; ++i) {
+    const int diff_uv = ref[i] - src[i];
+    dst[i] += diff_uv;
+  }
+}
+
+static void SharpYUVFilterRow_NEON(const int16_t* A, const int16_t* B, int len,
+                                   const uint16_t* best_y, uint16_t* out) {
+  int i;
+  const int16x8_t max = vdupq_n_s16(MAX_Y);
+  const int16x8_t zero = vdupq_n_s16(0);
+  for (i = 0; i + 8 <= len; i += 8) {
+    const int16x8_t a0 = vld1q_s16(A + i + 0);
+    const int16x8_t a1 = vld1q_s16(A + i + 1);
+    const int16x8_t b0 = vld1q_s16(B + i + 0);
+    const int16x8_t b1 = vld1q_s16(B + i + 1);
+    const int16x8_t a0b1 = vaddq_s16(a0, b1);
+    const int16x8_t a1b0 = vaddq_s16(a1, b0);
+    const int16x8_t a0a1b0b1 = vaddq_s16(a0b1, a1b0);  // A0+A1+B0+B1
+    const int16x8_t a0b1_2 = vaddq_s16(a0b1, a0b1);    // 2*(A0+B1)
+    const int16x8_t a1b0_2 = vaddq_s16(a1b0, a1b0);    // 2*(A1+B0)
+    const int16x8_t c0 = vshrq_n_s16(vaddq_s16(a0b1_2, a0a1b0b1), 3);
+    const int16x8_t c1 = vshrq_n_s16(vaddq_s16(a1b0_2, a0a1b0b1), 3);
+    const int16x8_t d0 = vaddq_s16(c1, a0);
+    const int16x8_t d1 = vaddq_s16(c0, a1);
+    const int16x8_t e0 = vrshrq_n_s16(d0, 1);
+    const int16x8_t e1 = vrshrq_n_s16(d1, 1);
+    const int16x8x2_t f = vzipq_s16(e0, e1);
+    const int16x8_t g0 = vreinterpretq_s16_u16(vld1q_u16(best_y + 2 * i + 0));
+    const int16x8_t g1 = vreinterpretq_s16_u16(vld1q_u16(best_y + 2 * i + 8));
+    const int16x8_t h0 = vaddq_s16(g0, f.val[0]);
+    const int16x8_t h1 = vaddq_s16(g1, f.val[1]);
+    const int16x8_t i0 = vmaxq_s16(vminq_s16(h0, max), zero);
+    const int16x8_t i1 = vmaxq_s16(vminq_s16(h1, max), zero);
+    vst1q_u16(out + 2 * i + 0, vreinterpretq_u16_s16(i0));
+    vst1q_u16(out + 2 * i + 8, vreinterpretq_u16_s16(i1));
+  }
+  for (; i < len; ++i) {
+    const int a0b1 = A[i + 0] + B[i + 1];
+    const int a1b0 = A[i + 1] + B[i + 0];
+    const int a0a1b0b1 = a0b1 + a1b0 + 8;
+    const int v0 = (8 * A[i + 0] + 2 * a1b0 + a0a1b0b1) >> 4;
+    const int v1 = (8 * A[i + 1] + 2 * a0b1 + a0a1b0b1) >> 4;
+    out[2 * i + 0] = clip_y(best_y[2 * i + 0] + v0);
+    out[2 * i + 1] = clip_y(best_y[2 * i + 1] + v1);
+  }
+}
+#undef MAX_Y
+
+//------------------------------------------------------------------------------
+
+extern void WebPInitSharpYUVNEON(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void WebPInitSharpYUVNEON(void) {
+  WebPSharpYUVUpdateY = SharpYUVUpdateY_NEON;
+  WebPSharpYUVUpdateRGB = SharpYUVUpdateRGB_NEON;
+  WebPSharpYUVFilterRow = SharpYUVFilterRow_NEON;
+}
+
+#else  // !WEBP_USE_NEON
+
+WEBP_DSP_INIT_STUB(WebPInitSamplersNEON)
+WEBP_DSP_INIT_STUB(WebPInitConvertARGBToYUVNEON)
+WEBP_DSP_INIT_STUB(WebPInitSharpYUVNEON)
+
+#endif  // WEBP_USE_NEON