SSE4.1 implementation of some lossless encoding functions

New implementations: SubtractGreenFromBlueAndRed and TransformColor

around 1-2% faster lossless encoding.

Change-Id: I1668e36fdc316ba55b3b798b91b4a3e36ce62861

Android.mk

@@ -86,6 +86,7 @@ dsp_enc_srcs := \
     src/dsp/lossless_enc_mips_dsp_r2.c \
     src/dsp/lossless_enc_neon.$(NEON) \
     src/dsp/lossless_enc_sse2.c \
+    src/dsp/lossless_enc_sse41.c \
 
 enc_srcs := \
     src/enc/alpha.c \

Makefile.vc

@@ -237,6 +237,7 @@ DSP_ENC_OBJS = \
     $(DIROBJ)\dsp\lossless_enc_mips_dsp_r2.obj \
     $(DIROBJ)\dsp\lossless_enc_neon.obj \
     $(DIROBJ)\dsp\lossless_enc_sse2.obj \
+    $(DIROBJ)\dsp\lossless_enc_sse41.obj \
 
 EX_ANIM_UTIL_OBJS = \
     $(DIROBJ)\examples\anim_util.obj \

makefile.unix

@@ -177,6 +177,7 @@ DSP_ENC_OBJS = \
     src/dsp/lossless_enc_mips_dsp_r2.o \
     src/dsp/lossless_enc_neon.o \
     src/dsp/lossless_enc_sse2.o \
+    src/dsp/lossless_enc_sse41.o \
 
 ENC_OBJS = \
     src/enc/alpha.o \

src/dsp/Makefile.am

@@ -86,6 +86,7 @@ libwebpdsp_sse2_la_LIBADD = libwebpdspdecode_sse2.la
 
 libwebpdsp_sse41_la_SOURCES =
 libwebpdsp_sse41_la_SOURCES += enc_sse41.c
+libwebpdsp_sse41_la_SOURCES += lossless_enc_sse41.c
 libwebpdsp_sse41_la_CPPFLAGS = $(libwebpdsp_la_CPPFLAGS)
 libwebpdsp_sse41_la_CFLAGS = $(AM_CFLAGS) $(SSE41_FLAGS)
 libwebpdsp_sse41_la_LIBADD = libwebpdspdecode_sse41.la

src/dsp/lossless_enc.c

@@ -1221,6 +1221,7 @@ VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount;
 VP8LHistogramAddFunc VP8LHistogramAdd;
 
 extern void VP8LEncDspInitSSE2(void);
+extern void VP8LEncDspInitSSE41(void);
 extern void VP8LEncDspInitNEON(void);
 extern void VP8LEncDspInitMIPS32(void);
 extern void VP8LEncDspInitMIPSdspR2(void);
@@ -1256,6 +1257,11 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInit(void) {
 #if defined(WEBP_USE_SSE2)
     if (VP8GetCPUInfo(kSSE2)) {
       VP8LEncDspInitSSE2();
+#if defined(WEBP_USE_SSE41)
+      if (VP8GetCPUInfo(kSSE4_1)) {
+        VP8LEncDspInitSSE41();
+      }
+#endif
     }
 #endif
 #if defined(WEBP_USE_NEON)

src/dsp/lossless_enc_sse41.c

@@ -0,0 +1,86 @@
+// Copyright 2015 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.
+// -----------------------------------------------------------------------------
+//
+// SSE4.1 variant of methods for lossless encoder
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "./dsp.h"
+
+#if defined(WEBP_USE_SSE41)
+#include <assert.h>
+#include <smmintrin.h>
+#include "./lossless.h"
+
+//------------------------------------------------------------------------------
+// Subtract-Green Transform
+
+static void SubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixels) {
+  int i;
+  const __m128i kCstShuffle = _mm_set_epi8(-1, 13, -1, 13, -1, 9, -1, 9,
+                                           -1,  5, -1,  5, -1, 1, -1, 1);
+  for (i = 0; i + 4 <= num_pixels; i += 4) {
+    const __m128i in = _mm_loadu_si128((__m128i*)&argb_data[i]);
+    const __m128i in_0g0g = _mm_shuffle_epi8(in, kCstShuffle);
+    const __m128i out = _mm_sub_epi8(in, in_0g0g);
+    _mm_storeu_si128((__m128i*)&argb_data[i], out);
+  }
+  // fallthrough and finish off with plain-C
+  VP8LSubtractGreenFromBlueAndRed_C(argb_data + i, num_pixels - i);
+}
+
+//------------------------------------------------------------------------------
+// Color Transform
+
+static WEBP_INLINE void TransformColor(const VP8LMultipliers* const m,
+                                       uint32_t* argb_data, int num_pixels) {
+  // Shuffle constant to spread green and red to some *upper* byte locations.
+  const __m128i kCst_g0rg = _mm_set_epi8(5, -1,  -1, -1, 6, -1, 5, -1,
+                                         1, -1,  -1, -1, 2, -1, 1, -1);
+  // Shuffling constant to collect deltas from uint32 to uint8 locations.
+  const __m128i kCstShuffle = _mm_set_epi8(-1, -1, -1, -1, -1, -1, -1, -1,
+                                           -1, 12, -1,  8, -1,  4, -1,  0);
+  // Used to collect the two parts of the delta (horizontal add) with madd.
+  const __m128i kCstAdd = _mm_set1_epi16(1);
+  // sign-extended multiplying constants, pre-shifted by 5.
+#define CST(X)  (((int16_t)(m->X << 8)) >> 5)   // sign-extend
+  const __m128i mults = _mm_set_epi16(
+      CST(green_to_red_), 0, CST(red_to_blue_), CST(green_to_blue_),
+      CST(green_to_red_), 0, CST(red_to_blue_), CST(green_to_blue_));
+#undef CST
+
+  int i;
+  for (i = 0; i + 2 <= num_pixels; i += 2) {
+    const __m128i in = _mm_loadl_epi64((__m128i*)&argb_data[i]); // argb
+    const __m128i A = _mm_shuffle_epi8(in, kCst_g0rg);     // g | 0 | r | g
+    const __m128i B = _mm_mulhi_epi16(A, mults);           // dr | 0 | db1 | db2
+    const __m128i C = _mm_madd_epi16(B, kCstAdd);          // dr | 0 | db | 0
+    const __m128i D = _mm_shuffle_epi8(C, kCstShuffle);    // 0 | dr | 0 | db
+    const __m128i out = _mm_sub_epi8(in, D);
+    _mm_storel_epi64((__m128i*)&argb_data[i], out);
+  }
+  // fallthrough and finish off with plain-C
+  VP8LTransformColor_C(m, argb_data + i, num_pixels - i);
+}
+
+//------------------------------------------------------------------------------
+// Entry point
+
+extern void VP8LEncDspInitSSE41(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitSSE41(void) {
+  VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed;
+  VP8LTransformColor = TransformColor;
+}
+
+#else  // !WEBP_USE_SSE41
+
+WEBP_DSP_INIT_STUB(VP8LEncDspInitSSE41)
+
+#endif  // WEBP_USE_SSE41