SkColor_opts_SSE2.h revision 6dbfb21a6c88af6d94e8c823c3ad559f1a41b493 
1/*
2 * Copyright 2014 The Android Open Source Project
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#ifndef SkColor_opts_SSE2_DEFINED
9#define SkColor_opts_SSE2_DEFINED
10
11#include <emmintrin.h>
12
13#define ASSERT_EQ(a,b) SkASSERT(0xffff == _mm_movemask_epi8(_mm_cmpeq_epi8((a), (b))))
14
15// Because no _mm_mul_epi32() in SSE2, we emulate it here.
16// Multiplies 4 32-bit integers from a by 4 32-bit intergers from b.
17// The 4 multiplication results should be represented within 32-bit
18// integers, otherwise they would be overflow.
19static inline  __m128i Multiply32_SSE2(const __m128i& a, const __m128i& b) {
20    // Calculate results of a0 * b0 and a2 * b2.
21    __m128i r1 = _mm_mul_epu32(a, b);
22    // Calculate results of a1 * b1 and a3 * b3.
23    __m128i r2 = _mm_mul_epu32(_mm_srli_si128(a, 4), _mm_srli_si128(b, 4));
24    // Shuffle results to [63..0] and interleave the results.
25    __m128i r = _mm_unpacklo_epi32(_mm_shuffle_epi32(r1, _MM_SHUFFLE(0,0,2,0)),
26                                   _mm_shuffle_epi32(r2, _MM_SHUFFLE(0,0,2,0)));
27    return r;
28}
29
30static inline __m128i SkAlpha255To256_SSE2(const __m128i& alpha) {
31    return _mm_add_epi32(alpha, _mm_set1_epi32(1));
32}
33
34// See #define SkAlphaMulAlpha(a, b)  SkMulDiv255Round(a, b) in SkXfermode.cpp.
35static inline __m128i SkAlphaMulAlpha_SSE2(const __m128i& a,
36                                           const __m128i& b) {
37    __m128i prod = _mm_mullo_epi16(a, b);
38    prod = _mm_add_epi32(prod, _mm_set1_epi32(128));
39    prod = _mm_add_epi32(prod, _mm_srli_epi32(prod, 8));
40    prod = _mm_srli_epi32(prod, 8);
41
42    return prod;
43}
44
45// Portable version SkAlphaMulQ is in SkColorPriv.h.
46static inline __m128i SkAlphaMulQ_SSE2(const __m128i& c, const __m128i& scale) {
47    const __m128i mask = _mm_set1_epi32(0xFF00FF);
48    __m128i s = _mm_or_si128(_mm_slli_epi32(scale, 16), scale);
49
50    // uint32_t rb = ((c & mask) * scale) >> 8
51    __m128i rb = _mm_and_si128(mask, c);
52    rb = _mm_mullo_epi16(rb, s);
53    rb = _mm_srli_epi16(rb, 8);
54
55    // uint32_t ag = ((c >> 8) & mask) * scale
56    __m128i ag = _mm_srli_epi16(c, 8);
57    ASSERT_EQ(ag, _mm_and_si128(mask, ag));  // ag = _mm_srli_epi16(c, 8) did this for us.
58    ag = _mm_mullo_epi16(ag, s);
59
60    // (rb & mask) | (ag & ~mask)
61    ASSERT_EQ(rb, _mm_and_si128(mask, rb));  // rb = _mm_srli_epi16(rb, 8) did this for us.
62    ag = _mm_andnot_si128(mask, ag);
63    return _mm_or_si128(rb, ag);
64}
65
66// Fast path for SkAlphaMulQ_SSE2 with a constant scale factor.
67static inline __m128i SkAlphaMulQ_SSE2(const __m128i& c, const unsigned scale) {
68    const __m128i mask = _mm_set1_epi32(0xFF00FF);
69    __m128i s = _mm_set1_epi16(scale << 8); // Move scale factor to upper byte of word.
70
71    // With mulhi, red and blue values are already in the right place and
72    // don't need to be divided by 256.
73    __m128i rb = _mm_and_si128(mask, c);
74    rb = _mm_mulhi_epu16(rb, s);
75
76    __m128i ag = _mm_andnot_si128(mask, c);
77    ag = _mm_mulhi_epu16(ag, s);     // Alpha and green values are in the higher byte of each word.
78    ag = _mm_andnot_si128(mask, ag);
79
80    return _mm_or_si128(rb, ag);
81}
82
83static inline __m128i SkGetPackedA32_SSE2(const __m128i& src) {
84#if SK_A32_SHIFT == 24                // It's very common (universal?) that alpha is the top byte.
85    return _mm_srli_epi32(src, 24);   // You'd hope the compiler would remove the left shift then,
86#else                                 // but I've seen Clang just do a dumb left shift of zero. :(
87    __m128i a = _mm_slli_epi32(src, (24 - SK_A32_SHIFT));
88    return _mm_srli_epi32(a, 24);
89#endif
90}
91
92static inline __m128i SkGetPackedR32_SSE2(const __m128i& src) {
93    __m128i r = _mm_slli_epi32(src, (24 - SK_R32_SHIFT));
94    return _mm_srli_epi32(r, 24);
95}
96
97static inline __m128i SkGetPackedG32_SSE2(const __m128i& src) {
98    __m128i g = _mm_slli_epi32(src, (24 - SK_G32_SHIFT));
99    return _mm_srli_epi32(g, 24);
100}
101
102static inline __m128i SkGetPackedB32_SSE2(const __m128i& src) {
103    __m128i b = _mm_slli_epi32(src, (24 - SK_B32_SHIFT));
104    return _mm_srli_epi32(b, 24);
105}
106
107static inline __m128i SkMul16ShiftRound_SSE2(const __m128i& a,
108                                             const __m128i& b, int shift) {
109    __m128i prod = _mm_mullo_epi16(a, b);
110    prod = _mm_add_epi16(prod, _mm_set1_epi16(1 << (shift - 1)));
111    prod = _mm_add_epi16(prod, _mm_srli_epi16(prod, shift));
112    prod = _mm_srli_epi16(prod, shift);
113
114    return prod;
115}
116
117static inline __m128i SkPackRGB16_SSE2(const __m128i& r,
118                                       const __m128i& g, const __m128i& b) {
119    __m128i dr = _mm_slli_epi16(r, SK_R16_SHIFT);
120    __m128i dg = _mm_slli_epi16(g, SK_G16_SHIFT);
121    __m128i db = _mm_slli_epi16(b, SK_B16_SHIFT);
122
123    __m128i c = _mm_or_si128(dr, dg);
124    return _mm_or_si128(c, db);
125}
126
127static inline __m128i SkPackARGB32_SSE2(const __m128i& a, const __m128i& r,
128                                        const __m128i& g, const __m128i& b) {
129    __m128i da = _mm_slli_epi32(a, SK_A32_SHIFT);
130    __m128i dr = _mm_slli_epi32(r, SK_R32_SHIFT);
131    __m128i dg = _mm_slli_epi32(g, SK_G32_SHIFT);
132    __m128i db = _mm_slli_epi32(b, SK_B32_SHIFT);
133
134    __m128i c = _mm_or_si128(da, dr);
135    c = _mm_or_si128(c, dg);
136    return _mm_or_si128(c, db);
137}
138
139static inline __m128i SkPacked16ToR32_SSE2(const __m128i& src) {
140    __m128i r = _mm_srli_epi32(src, SK_R16_SHIFT);
141    r = _mm_and_si128(r, _mm_set1_epi32(SK_R16_MASK));
142    r = _mm_or_si128(_mm_slli_epi32(r, (8 - SK_R16_BITS)),
143                     _mm_srli_epi32(r, (2 * SK_R16_BITS - 8)));
144
145    return r;
146}
147
148static inline __m128i SkPacked16ToG32_SSE2(const __m128i& src) {
149    __m128i g = _mm_srli_epi32(src, SK_G16_SHIFT);
150    g = _mm_and_si128(g, _mm_set1_epi32(SK_G16_MASK));
151    g = _mm_or_si128(_mm_slli_epi32(g, (8 - SK_G16_BITS)),
152                     _mm_srli_epi32(g, (2 * SK_G16_BITS - 8)));
153
154    return g;
155}
156
157static inline __m128i SkPacked16ToB32_SSE2(const __m128i& src) {
158    __m128i b = _mm_srli_epi32(src, SK_B16_SHIFT);
159    b = _mm_and_si128(b, _mm_set1_epi32(SK_B16_MASK));
160    b = _mm_or_si128(_mm_slli_epi32(b, (8 - SK_B16_BITS)),
161                     _mm_srli_epi32(b, (2 * SK_B16_BITS - 8)));
162
163    return b;
164}
165
166static inline __m128i SkPixel16ToPixel32_SSE2(const __m128i& src) {
167    __m128i r = SkPacked16ToR32_SSE2(src);
168    __m128i g = SkPacked16ToG32_SSE2(src);
169    __m128i b = SkPacked16ToB32_SSE2(src);
170
171    return SkPackARGB32_SSE2(_mm_set1_epi32(0xFF), r, g, b);
172}
173
174static inline __m128i SkPixel32ToPixel16_ToU16_SSE2(const __m128i& src_pixel1,
175                                                    const __m128i& src_pixel2) {
176    // Calculate result r.
177    __m128i r1 = _mm_srli_epi32(src_pixel1,
178                                SK_R32_SHIFT + (8 - SK_R16_BITS));
179    r1 = _mm_and_si128(r1, _mm_set1_epi32(SK_R16_MASK));
180    __m128i r2 = _mm_srli_epi32(src_pixel2,
181                                SK_R32_SHIFT + (8 - SK_R16_BITS));
182    r2 = _mm_and_si128(r2, _mm_set1_epi32(SK_R16_MASK));
183    __m128i r = _mm_packs_epi32(r1, r2);
184
185    // Calculate result g.
186    __m128i g1 = _mm_srli_epi32(src_pixel1,
187                                SK_G32_SHIFT + (8 - SK_G16_BITS));
188    g1 = _mm_and_si128(g1, _mm_set1_epi32(SK_G16_MASK));
189    __m128i g2 = _mm_srli_epi32(src_pixel2,
190                                SK_G32_SHIFT + (8 - SK_G16_BITS));
191    g2 = _mm_and_si128(g2, _mm_set1_epi32(SK_G16_MASK));
192    __m128i g = _mm_packs_epi32(g1, g2);
193
194    // Calculate result b.
195    __m128i b1 = _mm_srli_epi32(src_pixel1,
196                                SK_B32_SHIFT + (8 - SK_B16_BITS));
197    b1 = _mm_and_si128(b1, _mm_set1_epi32(SK_B16_MASK));
198    __m128i b2 = _mm_srli_epi32(src_pixel2,
199                                SK_B32_SHIFT + (8 - SK_B16_BITS));
200    b2 = _mm_and_si128(b2, _mm_set1_epi32(SK_B16_MASK));
201    __m128i b = _mm_packs_epi32(b1, b2);
202
203    // Store 8 16-bit colors in dst.
204    __m128i d_pixel = SkPackRGB16_SSE2(r, g, b);
205
206    return d_pixel;
207}
208
209// Portable version is SkPMSrcOver in SkColorPriv.h.
210static inline __m128i SkPMSrcOver_SSE2(const __m128i& src, const __m128i& dst) {
211    return _mm_add_epi32(src,
212                         SkAlphaMulQ_SSE2(dst, _mm_sub_epi32(_mm_set1_epi32(256),
213                                                             SkGetPackedA32_SSE2(src))));
214}
215
216// Portable version is SkBlendARGB32 in SkColorPriv.h.
217static inline __m128i SkBlendARGB32_SSE2(const __m128i& src, const __m128i& dst,
218                                         const __m128i& aa) {
219    __m128i src_scale = SkAlpha255To256_SSE2(aa);
220    // SkAlpha255To256(255 - SkAlphaMul(SkGetPackedA32(src), src_scale))
221    __m128i dst_scale = SkGetPackedA32_SSE2(src);
222    dst_scale = _mm_mullo_epi16(dst_scale, src_scale);
223    dst_scale = _mm_srli_epi16(dst_scale, 8);
224    dst_scale = _mm_sub_epi32(_mm_set1_epi32(256), dst_scale);
225
226    __m128i result = SkAlphaMulQ_SSE2(src, src_scale);
227    return _mm_add_epi8(result, SkAlphaMulQ_SSE2(dst, dst_scale));
228}
229
230// Fast path for SkBlendARGB32_SSE2 with a constant alpha factor.
231static inline __m128i SkBlendARGB32_SSE2(const __m128i& src, const __m128i& dst,
232                                         const unsigned aa) {
233    unsigned alpha = SkAlpha255To256(aa);
234    __m128i src_scale = _mm_set1_epi32(alpha);
235    // SkAlpha255To256(255 - SkAlphaMul(SkGetPackedA32(src), src_scale))
236    __m128i dst_scale = SkGetPackedA32_SSE2(src);
237    dst_scale = _mm_mullo_epi16(dst_scale, src_scale);
238    dst_scale = _mm_srli_epi16(dst_scale, 8);
239    dst_scale = _mm_sub_epi32(_mm_set1_epi32(256), dst_scale);
240
241    __m128i result = SkAlphaMulQ_SSE2(src, alpha);
242    return _mm_add_epi8(result, SkAlphaMulQ_SSE2(dst, dst_scale));
243}
244
245#undef ASSERT_EQ
246#endif // SkColor_opts_SSE2_DEFINED
247