diff options
author | 2015-11-17 14:19:52 -0800 | |
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committer | 2015-11-17 14:19:52 -0800 | |
commit | cbf4fba43933302a846872e4c5ce8f1adb8b325e (patch) | |
tree | 96dad6cc0a2241544a0cf52cccdc7a0fbe89f9b1 /src/opts | |
parent | 56847a65648af4d06da9c26c55242949a1bf31ab (diff) |
div255(x) as ((x+128)*257)>>16 with SSE
_mm_mulhi_epu16 makes the (...*257)>>16 part simple.
This seems to speed up every transfermode that uses div255(),
in the 7-25% range.
It even appears to obviate the need for approxMulDiv255() on SSE.
I'm not sure about NEON yet, so I'll keep approxMulDiv255() for now.
Should be no pixels change:
https://gold.skia.org/search2?issue=1452903004&unt=true&query=source_type%3Dgm&master=false
BUG=skia:
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
Review URL: https://codereview.chromium.org/1452903004
Diffstat (limited to 'src/opts')
-rw-r--r-- | src/opts/Sk4px_NEON.h | 6 | ||||
-rw-r--r-- | src/opts/Sk4px_SSE2.h | 9 | ||||
-rw-r--r-- | src/opts/Sk4px_none.h | 6 |
3 files changed, 21 insertions, 0 deletions
diff --git a/src/opts/Sk4px_NEON.h b/src/opts/Sk4px_NEON.h index 89841d927e..c27bb13764 100644 --- a/src/opts/Sk4px_NEON.h +++ b/src/opts/Sk4px_NEON.h @@ -57,6 +57,12 @@ inline Sk4px Sk4px::Wide::addNarrowHi(const Sk16h& other) const { vaddhn_u16(this->fHi.fVec, o.fHi.fVec))); } +inline Sk4px Sk4px::Wide::div255() const { + // Calculated as ((x+128) + ((x+128)>>8)) >> 8. + auto v = *this + Sk16h(128); + return v.addNarrowHi(v>>8); +} + inline Sk4px Sk4px::alphas() const { auto as = vshrq_n_u32((uint32x4_t)fVec, SK_A32_SHIFT); // ___3 ___2 ___1 ___0 return Sk16b((uint8x16_t)vmulq_n_u32(as, 0x01010101)); // 3333 2222 1111 0000 diff --git a/src/opts/Sk4px_SSE2.h b/src/opts/Sk4px_SSE2.h index 9c3eb1210c..96f21db399 100644 --- a/src/opts/Sk4px_SSE2.h +++ b/src/opts/Sk4px_SSE2.h @@ -45,6 +45,15 @@ inline Sk4px Sk4px::Wide::addNarrowHi(const Sk16h& other) const { return Sk4px(_mm_packus_epi16(r.fLo.fVec, r.fHi.fVec)); } +inline Sk4px Sk4px::Wide::div255() const { + // (x + 127) / 255 == ((x+128) * 257)>>16, + // and _mm_mulhi_epu16 makes the (_ * 257)>>16 part very convenient. + const __m128i _128 = _mm_set1_epi16(128), + _257 = _mm_set1_epi16(257); + return Sk4px(_mm_packus_epi16(_mm_mulhi_epu16(_mm_add_epi16(fLo.fVec, _128), _257), + _mm_mulhi_epu16(_mm_add_epi16(fHi.fVec, _128), _257))); +} + // Load4Alphas and Load2Alphas use possibly-unaligned loads (SkAlpha[] -> uint16_t or uint32_t). // These are safe on x86, often with no speed penalty. diff --git a/src/opts/Sk4px_none.h b/src/opts/Sk4px_none.h index 540edb821d..efbd780c9f 100644 --- a/src/opts/Sk4px_none.h +++ b/src/opts/Sk4px_none.h @@ -62,6 +62,12 @@ inline Sk4px Sk4px::Wide::addNarrowHi(const Sk16h& other) const { r.kth<12>(), r.kth<13>(), r.kth<14>(), r.kth<15>()); } +inline Sk4px Sk4px::Wide::div255() const { + // Calculated as ((x+128) + ((x+128)>>8)) >> 8. + auto v = *this + Sk16h(128); + return v.addNarrowHi(v>>8); +} + inline Sk4px Sk4px::alphas() const { static_assert(SK_A32_SHIFT == 24, "This method assumes little-endian."); return Sk16b(this->kth< 3>(), this->kth< 3>(), this->kth< 3>(), this->kth< 3>(), |