1/* 2 * Copyright 2015 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8// For SkPMFloat(SkPMColor), we widen our 8 bit components (fix8) to 8-bit components in 32 bits 9// (fix8_32), then convert those to floats. 10 11// round() does the opposite, working from floats to 8-bit-in-32-bits, then back to packed 8 bit. 12 13// roundClamp() is the same as _SSE2: floats to 8-in-32, to 8-in-16, to packed 8 bit, with 14// _mm_packus_epi16() both clamping and narrowing. 15 16inline SkPMFloat::SkPMFloat(SkPMColor c) { 17 SkPMColorAssert(c); 18 const int _ = 255; // _ means to zero that byte. 19 __m128i fix8 = _mm_set_epi32(0,0,0,c), 20 fix8_32 = _mm_shuffle_epi8(fix8, _mm_set_epi8(_,_,_,3, _,_,_,2, _,_,_,1, _,_,_,0)); 21 fVec = _mm_cvtepi32_ps(fix8_32); 22 SkASSERT(this->isValid()); 23} 24 25inline SkPMColor SkPMFloat::trunc() const { 26 const int _ = 255; // _ means to zero that byte. 27 __m128i fix8_32 = _mm_cvttps_epi32(fVec), 28 fix8 = _mm_shuffle_epi8(fix8_32, _mm_set_epi8(_,_,_,_, _,_,_,_, _,_,_,_, 12,8,4,0)); 29 SkPMColor c = _mm_cvtsi128_si32(fix8); 30 SkPMColorAssert(c); 31 return c; 32} 33 34inline SkPMColor SkPMFloat::round() const { 35 return SkPMFloat(Sk4f(0.5f) + *this).trunc(); 36} 37 38inline SkPMColor SkPMFloat::roundClamp() const { 39 // We don't use _mm_cvtps_epi32, because we want precise control over how 0.5 rounds (up). 40 __m128i fix8_32 = _mm_cvttps_epi32(_mm_add_ps(_mm_set1_ps(0.5f), fVec)), 41 fix8_16 = _mm_packus_epi16(fix8_32, fix8_32), 42 fix8 = _mm_packus_epi16(fix8_16, fix8_16); 43 SkPMColor c = _mm_cvtsi128_si32(fix8); 44 SkPMColorAssert(c); 45 return c; 46} 47 48inline void SkPMFloat::From4PMColors(const SkPMColor colors[4], 49 SkPMFloat* a, SkPMFloat* b, SkPMFloat* c, SkPMFloat* d) { 50 // Haven't beaten this yet. 51 *a = FromPMColor(colors[0]); 52 *b = FromPMColor(colors[1]); 53 *c = FromPMColor(colors[2]); 54 *d = FromPMColor(colors[3]); 55} 56 57inline void SkPMFloat::RoundTo4PMColors( 58 const SkPMFloat& a, const SkPMFloat& b, const SkPMFloat&c, const SkPMFloat& d, 59 SkPMColor colors[4]) { 60 // Haven't beaten this yet. Still faster than RoundClampTo4PMColors? 61 colors[0] = a.round(); 62 colors[1] = b.round(); 63 colors[2] = c.round(); 64 colors[3] = d.round(); 65} 66 67inline void SkPMFloat::RoundClampTo4PMColors( 68 const SkPMFloat& a, const SkPMFloat& b, const SkPMFloat&c, const SkPMFloat& d, 69 SkPMColor colors[4]) { 70 // Same as _SSE2.h's. We use 3 _mm_packus_epi16() where the naive loop uses 8. 71 // We don't use _mm_cvtps_epi32, because we want precise control over how 0.5 rounds (up). 72 __m128i c0 = _mm_cvttps_epi32(_mm_add_ps(_mm_set1_ps(0.5f), a.fVec)), 73 c1 = _mm_cvttps_epi32(_mm_add_ps(_mm_set1_ps(0.5f), b.fVec)), 74 c2 = _mm_cvttps_epi32(_mm_add_ps(_mm_set1_ps(0.5f), c.fVec)), 75 c3 = _mm_cvttps_epi32(_mm_add_ps(_mm_set1_ps(0.5f), d.fVec)); 76 __m128i c3210 = _mm_packus_epi16(_mm_packus_epi16(c0, c1), 77 _mm_packus_epi16(c2, c3)); 78 _mm_storeu_si128((__m128i*)colors, c3210); 79 SkPMColorAssert(colors[0]); 80 SkPMColorAssert(colors[1]); 81 SkPMColorAssert(colors[2]); 82 SkPMColorAssert(colors[3]); 83} 84