diff options
Diffstat (limited to 'src')
-rw-r--r-- | src/opts/SkBlurImage_opts_SSE4.cpp | 37 |
1 files changed, 16 insertions, 21 deletions
diff --git a/src/opts/SkBlurImage_opts_SSE4.cpp b/src/opts/SkBlurImage_opts_SSE4.cpp index 81748af7b2..1359d04f1d 100644 --- a/src/opts/SkBlurImage_opts_SSE4.cpp +++ b/src/opts/SkBlurImage_opts_SSE4.cpp @@ -27,16 +27,11 @@ enum BlurDirection { * 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); + // ARGB -> 0000 0000 0000 ARGB + __m128i widened = _mm_cvtsi32_si128(a); + // SSE4.1 has xxxx xxxx xxxx ARGB -> 000A 000R 000G 000B as a one-stop-shop instruction. + // It can even work from memory, so a smart compiler probably merges in the _mm_cvtsi32_si128(). + return _mm_cvtepu8_epi32(widened); } template<BlurDirection srcDirection, BlurDirection dstDirection> @@ -50,9 +45,8 @@ void SkBoxBlur_SSE4(const SkPMColor* src, int srcStride, SkPMColor* dst, int ker 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; + __m128i sum = _mm_setzero_si128(); const SkPMColor* p = src; for (int i = 0; i < rightBorder; ++i) { sum = _mm_add_epi32(sum, expand(*p)); @@ -62,20 +56,20 @@ void SkBoxBlur_SSE4(const SkPMColor* src, int srcStride, SkPMColor* dst, int ker const SkPMColor* sptr = src; SkColor* dptr = dst; for (int x = 0; x < width; ++x) { - __m128i result = _mm_mullo_epi32(sum, scale); + // TODO(mtklein): We are working in 8.24 here. Drop to 8.8 when the kernel is narrow? - // sumA*scale+.5 sumB*scale+.5 sumG*scale+.5 sumB*scale+.5 + // Multiply each component by scale (i.e. divide by kernel size) and add half to round. + __m128i result = _mm_mullo_epi32(sum, scale); 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); + // Now pack the top byte of each 32-bit lane back down into one 32-bit color. + // Axxx Rxxx Gxxx Bxxx -> xxxx xxxx xxxx ARGB + const char _ = 0; // Don't care what ends up in these bytes. Happens to be byte 0. + result = _mm_shuffle_epi8(result, _mm_set_epi8(_,_,_,_, _,_,_,_, _,_,_,_, 15,11,7,3)); - // 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); + + // TODO(mtklein): experiment with breaking this loop into 3 parts if (x >= leftOffset) { SkColor l = *(sptr - leftOffset * srcStrideX); sum = _mm_sub_epi32(sum, expand(l)); @@ -86,6 +80,7 @@ void SkBoxBlur_SSE4(const SkPMColor* src, int srcStride, SkPMColor* dst, int ker } sptr += srcStrideX; if (srcDirection == kY) { + // TODO(mtklein): experiment with moving this prefetch forward _mm_prefetch(reinterpret_cast<const char*>(sptr + (rightOffset + 1) * srcStrideX), _MM_HINT_T0); } |