SSE2 implementation of RGBA box blurs. This yields ~2X perf improvement on Xeon ES-2690.
R=mtklein@google.com
Review URL: https://codereview.chromium.org/61643011
git-svn-id: http://skia.googlecode.com/svn/trunk@12204 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/opts/SkBlurImage_opts_SSE2.cpp b/src/opts/SkBlurImage_opts_SSE2.cpp
new file mode 100644
index 0000000..97cd2fd
--- /dev/null
+++ b/src/opts/SkBlurImage_opts_SSE2.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#include "SkBitmap.h"
+#include "SkColorPriv.h"
+#include "SkBlurImage_opts_SSE2.h"
+#include "SkRect.h"
+
+#include <emmintrin.h>
+
+namespace {
+
+enum BlurDirection {
+ kX, kY
+};
+
+/**
+ * Helper function to spread the components of a 32-bit integer into the
+ * lower 8 bits of each 32-bit element of an SSE register.
+ */
+
+inline __m128i expand(int a) {
+ const __m128i zero = _mm_setzero_si128();
+
+ // 0 0 0 0 0 0 0 0 0 0 0 0 A R G B
+ __m128i result = _mm_cvtsi32_si128(a);
+
+ // 0 0 0 0 0 0 0 0 0 A 0 R 0 G 0 B
+ result = _mm_unpacklo_epi8(result, zero);
+
+ // 0 0 0 A 0 0 0 R 0 0 0 G 0 0 0 B
+ return _mm_unpacklo_epi16(result, zero);
+}
+
+template<BlurDirection srcDirection, BlurDirection dstDirection>
+void SkBoxBlur_SSE2(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
+ int leftOffset, int rightOffset, int width, int height)
+{
+ const int rightBorder = SkMin32(rightOffset + 1, width);
+ const int srcStrideX = srcDirection == kX ? 1 : srcStride;
+ const int dstStrideX = dstDirection == kX ? 1 : height;
+ const int srcStrideY = srcDirection == kX ? srcStride : 1;
+ const int dstStrideY = dstDirection == kX ? width : 1;
+ const __m128i scale = _mm_set1_epi32((1 << 24) / kernelSize);
+ const __m128i half = _mm_set1_epi32(1 << 23);
+ const __m128i zero = _mm_setzero_si128();
+ for (int y = 0; y < height; ++y) {
+ __m128i sum = zero;
+ const SkPMColor* p = src;
+ for (int i = 0; i < rightBorder; ++i) {
+ sum = _mm_add_epi32(sum, expand(*p));
+ p += srcStrideX;
+ }
+
+ const SkPMColor* sptr = src;
+ SkColor* dptr = dst;
+ for (int x = 0; x < width; ++x) {
+#if 0
+ // In SSE4.1, this would be
+ __m128i result = _mm_mullo_epi32(sum, scale);
+#else
+ // But SSE2 has no PMULLUD, so we must do AG and RB separately.
+ __m128i tmp1 = _mm_mul_epu32(sum, scale);
+ __m128i tmp2 = _mm_mul_epu32(_mm_srli_si128(sum, 4),
+ _mm_srli_si128(scale, 4));
+ __m128i result = _mm_unpacklo_epi32(_mm_shuffle_epi32(tmp1, _MM_SHUFFLE(0,0,2,0)),
+ _mm_shuffle_epi32(tmp2, _MM_SHUFFLE(0,0,2,0)));
+#endif
+ // sumA*scale+.5 sumB*scale+.5 sumG*scale+.5 sumB*scale+.5
+ result = _mm_add_epi32(result, half);
+
+ // 0 0 0 A 0 0 0 R 0 0 0 G 0 0 0 B
+ result = _mm_srli_epi32(result, 24);
+
+ // 0 0 0 0 0 0 0 0 0 A 0 R 0 G 0 B
+ result = _mm_packs_epi32(result, zero);
+
+ // 0 0 0 0 0 0 0 0 0 0 0 0 A R G B
+ result = _mm_packus_epi16(result, zero);
+ *dptr = _mm_cvtsi128_si32(result);
+ if (x >= leftOffset) {
+ SkColor l = *(sptr - leftOffset * srcStrideX);
+ sum = _mm_sub_epi32(sum, expand(l));
+ }
+ if (x + rightOffset + 1 < width) {
+ SkColor r = *(sptr + (rightOffset + 1) * srcStrideX);
+ sum = _mm_add_epi32(sum, expand(r));
+ }
+ sptr += srcStrideX;
+ if (srcDirection == kY) {
+ _mm_prefetch(reinterpret_cast<const char*>(sptr + (rightOffset + 1) * srcStrideX),
+ _MM_HINT_T0);
+ }
+ dptr += dstStrideX;
+ }
+ src += srcStrideY;
+ dst += dstStrideY;
+ }
+}
+
+} // namespace
+
+bool SkBoxBlurGetPlatformProcs_SSE2(SkBoxBlurProc* boxBlurX,
+ SkBoxBlurProc* boxBlurY,
+ SkBoxBlurProc* boxBlurXY) {
+ *boxBlurX = SkBoxBlur_SSE2<kX, kX>;
+ *boxBlurY = SkBoxBlur_SSE2<kY, kY>;
+ *boxBlurXY = SkBoxBlur_SSE2<kX, kY>;
+ return true;
+}