Revert of 565 support for SIMD xfermodes

src/opts/Sk4px_SSE2.h

Index: src/opts/Sk4px_SSE2.h
diff --git a/src/opts/Sk4px_SSE2.h b/src/opts/Sk4px_SSE2.h
index 5e97abf308b3af30c3d6f3301c7101f0030a72c5..3809c5e47b5a955dfe6eeb794722c6950d8bb010 100644
--- a/src/opts/Sk4px_SSE2.h
+++ b/src/opts/Sk4px_SSE2.h
@@ -93,79 +93,4 @@
     return Sk16b(_mm_andnot_si128(_mm_set1_epi32(0xFF << SK_A32_SHIFT), this->fVec));
 }
 
-static inline __m128i widen_low_half_to_8888(__m128i v) {
-    // RGB565 format:   |R....|G.....|B....|
-    //           Bit:  16    11      5     0
-
-    // First get each pixel into its own 32-bit lane.
-    //      v == ____ ____  ____ ____  rgb3 rgb2  rgb1 rgb0
-    // spread == 0000 rgb3  0000 rgb2  0000 rgb1  0000 rgb0
-    auto spread = _mm_unpacklo_epi16(v, _mm_setzero_si128());
-
-    // Get each color independently, still in 565 precison but down at bit 0.
-    auto r5 = _mm_srli_epi32(spread, 11),
-         g6 = _mm_and_si128(_mm_set1_epi32(63), _mm_srli_epi32(spread,  5)),
-         b5 = _mm_and_si128(_mm_set1_epi32(31), spread);
-
-    // Scale 565 precision up to 8-bit each, filling low 323 bits with high bits of each component.
-    auto r8 = _mm_or_si128(_mm_slli_epi32(r5, 3), _mm_srli_epi32(r5, 2)),
-         g8 = _mm_or_si128(_mm_slli_epi32(g6, 2), _mm_srli_epi32(g6, 4)),
-         b8 = _mm_or_si128(_mm_slli_epi32(b5, 3), _mm_srli_epi32(b5, 2));
-
-    // Now put all the 8-bit components into SkPMColor order.
-    return _mm_or_si128(_mm_slli_epi32(r8, SK_R32_SHIFT),   // TODO: one of these shifts is zero...
-           _mm_or_si128(_mm_slli_epi32(g8, SK_G32_SHIFT),
-           _mm_or_si128(_mm_slli_epi32(b8, SK_B32_SHIFT),
-                        _mm_set1_epi32(0xFF << SK_A32_SHIFT))));
-}
-
-static inline __m128i narrow_to_565(__m128i w) {
-    // Extract out top RGB 565 bits of each pixel, with no rounding.
-    auto r5 = _mm_and_si128(_mm_set1_epi32(31), _mm_srli_epi32(w, SK_R32_SHIFT + 3)),
-         g6 = _mm_and_si128(_mm_set1_epi32(63), _mm_srli_epi32(w, SK_G32_SHIFT + 2)),
-         b5 = _mm_and_si128(_mm_set1_epi32(31), _mm_srli_epi32(w, SK_B32_SHIFT + 3));
-
-    // Now put the bits in place in the low 16-bits of each 32-bit lane.
-    auto spread = _mm_or_si128(_mm_slli_epi32(r5, 11),
-                  _mm_or_si128(_mm_slli_epi32(g6,  5),
-                               b5));
-
-    // We want to pack the bottom 16-bits of spread down into the low half of the register, v.
-    // spread == 0000 rgb3  0000 rgb2  0000 rgb1  0000 rgb0
-    //      v == ____ ____  ____ ____  rgb3 rgb2  rgb1 rgb0
-
-    // Ideally now we'd use _mm_packus_epi32(spread, <anything>) to pack v.  But that's from SSE4.
-    // With only SSE2, we need to use _mm_packs_epi32.  That does signed saturation, and
-    // we need to preserve all 16 bits.  So we pretend our data is signed by sign-extending first.
-    // TODO: is it faster to just _mm_shuffle_epi8 this when we have SSSE3?
-    auto signExtended = _mm_srai_epi32(_mm_slli_epi32(spread, 16), 16);
-    auto v = _mm_packs_epi32(signExtended, signExtended);
-    return v;
-}
-
-inline Sk4px Sk4px::Load4(const SkPMColor16 src[4]) {
-    return Sk16b(widen_low_half_to_8888(_mm_loadl_epi64((const __m128i*)src)));
-}
-inline Sk4px Sk4px::Load2(const SkPMColor16 src[2]) {
-    auto src2 = ((uint32_t)src[0]      )
-              | ((uint32_t)src[1] << 16);
-    return Sk16b(widen_low_half_to_8888(_mm_cvtsi32_si128(src2)));
-}
-inline Sk4px Sk4px::Load1(const SkPMColor16 src[1]) {
-    return Sk16b(widen_low_half_to_8888(_mm_insert_epi16(_mm_setzero_si128(), src[0], 0)));
-}
-
-inline void Sk4px::store4(SkPMColor16 dst[4]) const {
-    _mm_storel_epi64((__m128i*)dst, narrow_to_565(this->fVec));
-}
-inline void Sk4px::store2(SkPMColor16 dst[2]) const {
-    uint32_t dst2 = _mm_cvtsi128_si32(narrow_to_565(this->fVec));
-    dst[0] = dst2;
-    dst[1] = dst2 >> 16;
-}
-inline void Sk4px::store1(SkPMColor16 dst[1]) const {
-    uint32_t dst2 = _mm_cvtsi128_si32(narrow_to_565(this->fVec));
-    dst[0] = dst2;
-}
-
 }  // namespace