SSE2-ified S32_alpha_D32_filter_DX (refactoring to come). Also shaved a few

cycles off the SSE2 blends.

Review URL:  http://codereview.appspot.com/171055



git-svn-id: http://skia.googlecode.com/svn/trunk@456 2bbb7eff-a529-9590-31e7-b0007b416f81

src/core/SkBitmapProcState.h

@@ -140,5 +140,7 @@ private:
 // platformProcs may test for them by name.
 void S32_opaque_D32_filter_DX(const SkBitmapProcState& s, const uint32_t xy[],
                               int count, SkPMColor colors[]);
+void S32_alpha_D32_filter_DX(const SkBitmapProcState& s, const uint32_t xy[],
+                             int count, SkPMColor colors[]);
 
 #endif

src/opts/SkBitmapProcState_opts_SSE2.cpp

@@ -124,3 +124,119 @@ void S32_opaque_D32_filter_DX_SSE2(const SkBitmapProcState& s,
         *colors++ = _mm_cvtsi128_si32(sum);
     } while (--count > 0);
 }
+
+void S32_alpha_D32_filter_DX_SSE2(const SkBitmapProcState& s,
+                                  const uint32_t* xy,
+                                  int count, uint32_t* colors) {
+    SkASSERT(count > 0 && colors != NULL);
+    SkASSERT(s.fDoFilter);
+    SkASSERT(s.fBitmap->config() == SkBitmap::kARGB_8888_Config);
+    SkASSERT(s.fAlphaScale < 256);
+
+    const char* srcAddr = static_cast<const char*>(s.fBitmap->getPixels());
+    unsigned rb = s.fBitmap->rowBytes();
+    uint32_t XY = *xy++;
+    unsigned y0 = XY >> 14;
+    const uint32_t* row0 = reinterpret_cast<const uint32_t*>(srcAddr + (y0 >> 4) * rb);
+    const uint32_t* row1 = reinterpret_cast<const uint32_t*>(srcAddr + (XY & 0x3FFF) * rb);
+    unsigned subY = y0 & 0xF;
+
+    // ( 0,  0,  0,  0,  0,  0,  0, 16)
+    __m128i sixteen = _mm_cvtsi32_si128(16);
+
+    // ( 0,  0,  0,  0, 16, 16, 16, 16)
+    sixteen = _mm_shufflelo_epi16(sixteen, 0);
+
+    // ( 0,  0,  0,  0,  0,  0,  0,  y)
+    __m128i allY = _mm_cvtsi32_si128(subY);
+
+    // ( 0,  0,  0,  0,  y,  y,  y,  y)
+    allY = _mm_shufflelo_epi16(allY, 0);
+
+    // ( 0,  0,  0,  0, 16-y, 16-y, 16-y, 16-y)
+    __m128i negY = _mm_sub_epi16(sixteen, allY);
+
+    // (16-y, 16-y, 16-y, 16-y, y, y, y, y)
+    allY = _mm_unpacklo_epi64(allY, negY);
+
+    // (16, 16, 16, 16, 16, 16, 16, 16 )
+    sixteen = _mm_shuffle_epi32(sixteen, 0);
+
+    // ( 0,  0,  0,  0,  0,  0,  0,  0)
+    __m128i zero = _mm_setzero_si128();
+
+    // ( alpha, alpha, alpha, alpha, alpha, alpha, alpha, alpha )
+    __m128i alpha = _mm_set1_epi16(s.fAlphaScale);
+
+    do {
+        uint32_t XX = *xy++;    // x0:14 | 4 | x1:14
+        unsigned x0 = XX >> 18;
+        unsigned x1 = XX & 0x3FFF;
+
+        // (0, 0, 0, 0, 0, 0, 0, x)
+        __m128i allX = _mm_cvtsi32_si128((XX >> 14) & 0x0F);
+        
+        // (0, 0, 0, 0, x, x, x, x)
+        allX = _mm_shufflelo_epi16(allX, 0);
+
+        // (x, x, x, x, x, x, x, x)
+        allX = _mm_shuffle_epi32(allX, 0);
+
+        // (16-x, 16-x, 16-x, 16-x, 16-x, 16-x, 16-x)
+        __m128i negX = _mm_sub_epi16(sixteen, allX);
+
+        // Load 4 samples (pixels).
+        __m128i a00 = _mm_cvtsi32_si128(row0[x0]);
+        __m128i a01 = _mm_cvtsi32_si128(row0[x1]);
+        __m128i a10 = _mm_cvtsi32_si128(row1[x0]);
+        __m128i a11 = _mm_cvtsi32_si128(row1[x1]);
+
+        // (0, 0, a00, a10)
+        __m128i a00a10 = _mm_unpacklo_epi32(a10, a00);
+
+        // Expand to 16 bits per component.
+        a00a10 = _mm_unpacklo_epi8(a00a10, zero);
+
+        // ((a00 * (16-y)), (a10 * y)).
+        a00a10 = _mm_mullo_epi16(a00a10, allY);
+
+        // (a00 * (16-y) * (16-x), a10 * y * (16-x)).
+        a00a10 = _mm_mullo_epi16(a00a10, negX);
+
+        // (0, 0, a01, a10)
+        __m128i a01a11 = _mm_unpacklo_epi32(a11, a01);
+
+        // Expand to 16 bits per component.
+        a01a11 = _mm_unpacklo_epi8(a01a11, zero);
+
+        // (a01 * (16-y)), (a11 * y)
+        a01a11 = _mm_mullo_epi16(a01a11, allY);
+
+        // (a01 * (16-y) * x), (a11 * y * x)
+        a01a11 = _mm_mullo_epi16(a01a11, allX);
+
+        // (a00*w00 + a01*w01, a10*w10 + a11*w11)
+        __m128i sum = _mm_add_epi16(a00a10, a01a11);
+
+        // (DC, a00*w00 + a01*w01)
+        __m128i shifted = _mm_shuffle_epi32(sum, 0xEE);
+
+        // (DC, a00*w00 + a01*w01 + a10*w10 + a11*w11)
+        sum = _mm_add_epi16(sum, shifted);
+
+        // Divide each 16 bit component by 256.
+        sum = _mm_srli_epi16(sum, 8);
+
+        // Multiply by alpha.
+        sum = _mm_mullo_epi16(sum, alpha);
+
+        // Divide each 16 bit component by 256.
+        sum = _mm_srli_epi16(sum, 8);
+
+        // Pack lower 4 16 bit values of sum into lower 4 bytes.
+        sum = _mm_packus_epi16(sum, zero);
+
+        // Extract low int and store.
+        *colors++ = _mm_cvtsi128_si32(sum);
+    } while (--count > 0);
+}

src/opts/SkBitmapProcState_opts_SSE2.h

@@ -20,3 +20,6 @@
 void S32_opaque_D32_filter_DX_SSE2(const SkBitmapProcState& s,
                                    const uint32_t* xy,
                                    int count, uint32_t* colors);
+void S32_alpha_D32_filter_DX_SSE2(const SkBitmapProcState& s,
+                                  const uint32_t* xy,
+                                  int count, uint32_t* colors);

src/opts/SkBlitRow_opts_SSE2.cpp

@@ -125,8 +125,7 @@ void S32A_Opaque_BlitRow32_SSE2(SkPMColor* SK_RESTRICT dst,
             __m128i dst_pixel = _mm_load_si128(d);
 
             __m128i dst_rb = _mm_and_si128(rb_mask, dst_pixel);
-            __m128i dst_ag = _mm_andnot_si128(rb_mask, dst_pixel);
-            dst_ag = _mm_srli_epi16(dst_ag, 8);
+            __m128i dst_ag = _mm_srli_epi16(dst_pixel, 8);
             // Shift alphas down to lower 8 bits of each quad.
             __m128i alpha = _mm_srli_epi32(src_pixel, 24);
 
@@ -174,13 +173,16 @@ void S32A_Opaque_BlitRow32_SSE2(SkPMColor* SK_RESTRICT dst,
             __m128i dst_pixel = _mm_load_si128(d);
 
             __m128i dst_rb = _mm_and_si128(rb_mask, dst_pixel);
-            __m128i dst_ag = _mm_andnot_si128(rb_mask, dst_pixel);
-            dst_ag = _mm_srli_epi16(dst_ag, 8);
-            // Shift alphas down to lower 8 bits of each quad.
-            __m128i alpha = _mm_srli_epi32(src_pixel, 24);
+            __m128i dst_ag = _mm_srli_epi16(dst_pixel, 8);
 
-            // Copy alpha to upper 3rd byte of each quad
-            alpha = _mm_or_si128(alpha, _mm_slli_epi32(alpha, 16));
+            // (a0, g0, a1, g1, a2, g2, a3, g3)  (low byte of each word)
+            __m128i alpha = _mm_srli_epi16(src_pixel, 8);
+
+            // (a0, a0, a1, a1, a2, g2, a3, g3)
+            alpha = _mm_shufflehi_epi16(alpha, 0xF5);
+
+            // (a0, a0, a1, a1, a2, a2, a3, a3)
+            alpha = _mm_shufflelo_epi16(alpha, 0xF5);
 
             // Subtract alphas from 256, to get 1..256
             alpha = _mm_sub_epi16(c_256, alpha);

src/opts/opts_check_SSE2.cpp

@@ -69,6 +69,8 @@ void SkBitmapProcState::platformProcs() {
     if (hasSSE2()) {
         if (fSampleProc32 == S32_opaque_D32_filter_DX) {
             fSampleProc32 = S32_opaque_D32_filter_DX_SSE2;
+        } else if (fSampleProc32 == S32_alpha_D32_filter_DX) {
+            fSampleProc32 = S32_alpha_D32_filter_DX_SSE2;
         }
     }
 }