Add an SSE4 version of some lossless color transforms.

Change-Id: Ieac094f684116d1292793b2ca321f6f1a69565b5

src/dsp/lossless_enc_sse41.c

@@ -18,6 +18,9 @@
 #include <smmintrin.h>
 #include "src/dsp/lossless.h"
 
+// For sign-extended multiplying constants, pre-shifted by 5:
+#define CST_5b(X)  (((int16_t)((uint16_t)(X) << 8)) >> 5)
+
 //------------------------------------------------------------------------------
 // Subtract-Green Transform
 
@@ -38,6 +41,95 @@ static void SubtractGreenFromBlueAndRed_SSE41(uint32_t* argb_data,
   }
 }
 
+//------------------------------------------------------------------------------
+// Color Transform
+
+#define SPAN 8
+static void CollectColorBlueTransforms_SSE41(const uint32_t* argb, int stride,
+                                             int tile_width, int tile_height,
+                                             int green_to_blue, int red_to_blue,
+                                             int histo[]) {
+  const __m128i mults_r = _mm_set1_epi16(CST_5b(red_to_blue));
+  const __m128i mults_g = _mm_set1_epi16(CST_5b(green_to_blue));
+  const __m128i mask_g = _mm_set1_epi16(0xff00);   // green mask
+  const __m128i mask_gb = _mm_set1_epi32(0xffff);  // green/blue mask
+  const __m128i mask_b = _mm_set1_epi16(0x00ff);   // blue mask
+  const __m128i shuffler_lo = _mm_setr_epi8(-1, 2, -1, 6, -1, 10, -1, 14, -1,
+                                            -1, -1, -1, -1, -1, -1, -1);
+  const __m128i shuffler_hi = _mm_setr_epi8(-1, -1, -1, -1, -1, -1, -1, -1, -1,
+                                            2, -1, 6, -1, 10, -1, 14);
+  int y;
+  for (y = 0; y < tile_height; ++y) {
+    const uint32_t* const src = argb + y * stride;
+    int i, x;
+    for (x = 0; x + SPAN <= tile_width; x += SPAN) {
+      uint16_t values[SPAN];
+      const __m128i in0 = _mm_loadu_si128((__m128i*)&src[x + 0]);
+      const __m128i in1 = _mm_loadu_si128((__m128i*)&src[x + SPAN / 2]);
+      const __m128i r0 = _mm_shuffle_epi8(in0, shuffler_lo);
+      const __m128i r1 = _mm_shuffle_epi8(in1, shuffler_hi);
+      const __m128i r = _mm_or_si128(r0, r1);         // r 0
+      const __m128i gb0 = _mm_and_si128(in0, mask_gb);
+      const __m128i gb1 = _mm_and_si128(in1, mask_gb);
+      const __m128i gb = _mm_packus_epi32(gb0, gb1);  // g b
+      const __m128i g = _mm_and_si128(gb, mask_g);    // g 0
+      const __m128i A = _mm_mulhi_epi16(r, mults_r);  // x dbr
+      const __m128i B = _mm_mulhi_epi16(g, mults_g);  // x dbg
+      const __m128i C = _mm_sub_epi8(gb, B);          // x b'
+      const __m128i D = _mm_sub_epi8(C, A);           // x b''
+      const __m128i E = _mm_and_si128(D, mask_b);     // 0 b''
+      _mm_storeu_si128((__m128i*)values, E);
+      for (i = 0; i < SPAN; ++i) ++histo[values[i]];
+    }
+  }
+  {
+    const int left_over = tile_width & (SPAN - 1);
+    if (left_over > 0) {
+      VP8LCollectColorBlueTransforms_C(argb + tile_width - left_over, stride,
+                                       left_over, tile_height,
+                                       green_to_blue, red_to_blue, histo);
+    }
+  }
+}
+
+static void CollectColorRedTransforms_SSE41(const uint32_t* argb, int stride,
+                                            int tile_width, int tile_height,
+                                            int green_to_red, int histo[]) {
+  const __m128i mults_g = _mm_set1_epi16(CST_5b(green_to_red));
+  const __m128i mask_g = _mm_set1_epi32(0x00ff00);  // green mask
+  const __m128i mask = _mm_set1_epi16(0xff);
+
+  int y;
+  for (y = 0; y < tile_height; ++y) {
+    const uint32_t* const src = argb + y * stride;
+    int i, x;
+    for (x = 0; x + SPAN <= tile_width; x += SPAN) {
+      uint16_t values[SPAN];
+      const __m128i in0 = _mm_loadu_si128((__m128i*)&src[x + 0]);
+      const __m128i in1 = _mm_loadu_si128((__m128i*)&src[x + SPAN / 2]);
+      const __m128i g0 = _mm_and_si128(in0, mask_g);  // 0 0  | g 0
+      const __m128i g1 = _mm_and_si128(in1, mask_g);
+      const __m128i g = _mm_packus_epi32(g0, g1);     // g 0
+      const __m128i A0 = _mm_srli_epi32(in0, 16);     // 0 0  | x r
+      const __m128i A1 = _mm_srli_epi32(in1, 16);
+      const __m128i A = _mm_packus_epi32(A0, A1);     // x r
+      const __m128i B = _mm_mulhi_epi16(g, mults_g);  // x dr
+      const __m128i C = _mm_sub_epi8(A, B);           // x r'
+      const __m128i D = _mm_and_si128(C, mask);       // 0 r'
+      _mm_storeu_si128((__m128i*)values, D);
+      for (i = 0; i < SPAN; ++i) ++histo[values[i]];
+    }
+  }
+  {
+    const int left_over = tile_width & (SPAN - 1);
+    if (left_over > 0) {
+      VP8LCollectColorRedTransforms_C(argb + tile_width - left_over, stride,
+                                      left_over, tile_height, green_to_red,
+                                      histo);
+    }
+  }
+}
+
 //------------------------------------------------------------------------------
 // Entry point
 
@@ -45,6 +137,8 @@ extern void VP8LEncDspInitSSE41(void);
 
 WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitSSE41(void) {
   VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed_SSE41;
+  VP8LCollectColorBlueTransforms = CollectColorBlueTransforms_SSE41;
+  VP8LCollectColorRedTransforms = CollectColorRedTransforms_SSE41;
 }
 
 #else  // !WEBP_USE_SSE41