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1 // Copyright 2014 Google Inc. All Rights Reserved.
2 //
3 // Use of this source code is governed by a BSD-style license
4 // that can be found in the COPYING file in the root of the source
5 // tree. An additional intellectual property rights grant can be found
6 // in the file PATENTS. All contributing project authors may
7 // be found in the AUTHORS file in the root of the source tree.
8 // -----------------------------------------------------------------------------
9 //
10 // YUV->RGB conversion functions
11 //
12 // Author: Skal (pascal.massimino@gmail.com)
13 
14 #include "./yuv.h"
15 
16 #if defined(WEBP_USE_SSE2)
17 
18 #include "./common_sse2.h"
19 #include <stdlib.h>
20 #include <emmintrin.h>
21 
22 //-----------------------------------------------------------------------------
23 // Convert spans of 32 pixels to various RGB formats for the fancy upsampler.
24 
25 // These constants are 14b fixed-point version of ITU-R BT.601 constants.
26 // R = (19077 * y             + 26149 * v - 14234) >> 6
27 // G = (19077 * y -  6419 * u - 13320 * v +  8708) >> 6
28 // B = (19077 * y + 33050 * u             - 17685) >> 6
ConvertYUV444ToRGB(const __m128i * const Y0,const __m128i * const U0,const __m128i * const V0,__m128i * const R,__m128i * const G,__m128i * const B)29 static void ConvertYUV444ToRGB(const __m128i* const Y0,
30                                const __m128i* const U0,
31                                const __m128i* const V0,
32                                __m128i* const R,
33                                __m128i* const G,
34                                __m128i* const B) {
35   const __m128i k19077 = _mm_set1_epi16(19077);
36   const __m128i k26149 = _mm_set1_epi16(26149);
37   const __m128i k14234 = _mm_set1_epi16(14234);
38   // 33050 doesn't fit in a signed short: only use this with unsigned arithmetic
39   const __m128i k33050 = _mm_set1_epi16((short)33050);
40   const __m128i k17685 = _mm_set1_epi16(17685);
41   const __m128i k6419  = _mm_set1_epi16(6419);
42   const __m128i k13320 = _mm_set1_epi16(13320);
43   const __m128i k8708  = _mm_set1_epi16(8708);
44 
45   const __m128i Y1 = _mm_mulhi_epu16(*Y0, k19077);
46 
47   const __m128i R0 = _mm_mulhi_epu16(*V0, k26149);
48   const __m128i R1 = _mm_sub_epi16(Y1, k14234);
49   const __m128i R2 = _mm_add_epi16(R1, R0);
50 
51   const __m128i G0 = _mm_mulhi_epu16(*U0, k6419);
52   const __m128i G1 = _mm_mulhi_epu16(*V0, k13320);
53   const __m128i G2 = _mm_add_epi16(Y1, k8708);
54   const __m128i G3 = _mm_add_epi16(G0, G1);
55   const __m128i G4 = _mm_sub_epi16(G2, G3);
56 
57   // be careful with the saturated *unsigned* arithmetic here!
58   const __m128i B0 = _mm_mulhi_epu16(*U0, k33050);
59   const __m128i B1 = _mm_adds_epu16(B0, Y1);
60   const __m128i B2 = _mm_subs_epu16(B1, k17685);
61 
62   // use logical shift for B2, which can be larger than 32767
63   *R = _mm_srai_epi16(R2, 6);   // range: [-14234, 30815]
64   *G = _mm_srai_epi16(G4, 6);   // range: [-10953, 27710]
65   *B = _mm_srli_epi16(B2, 6);   // range: [0, 34238]
66 }
67 
68 // Load the bytes into the *upper* part of 16b words. That's "<< 8", basically.
Load_HI_16(const uint8_t * src)69 static WEBP_INLINE __m128i Load_HI_16(const uint8_t* src) {
70   const __m128i zero = _mm_setzero_si128();
71   return _mm_unpacklo_epi8(zero, _mm_loadl_epi64((const __m128i*)src));
72 }
73 
74 // Load and replicate the U/V samples
Load_UV_HI_8(const uint8_t * src)75 static WEBP_INLINE __m128i Load_UV_HI_8(const uint8_t* src) {
76   const __m128i zero = _mm_setzero_si128();
77   const __m128i tmp0 = _mm_cvtsi32_si128(*(const uint32_t*)src);
78   const __m128i tmp1 = _mm_unpacklo_epi8(zero, tmp0);
79   return _mm_unpacklo_epi16(tmp1, tmp1);   // replicate samples
80 }
81 
82 // Convert 32 samples of YUV444 to R/G/B
YUV444ToRGB(const uint8_t * const y,const uint8_t * const u,const uint8_t * const v,__m128i * const R,__m128i * const G,__m128i * const B)83 static void YUV444ToRGB(const uint8_t* const y,
84                         const uint8_t* const u,
85                         const uint8_t* const v,
86                         __m128i* const R, __m128i* const G, __m128i* const B) {
87   const __m128i Y0 = Load_HI_16(y), U0 = Load_HI_16(u), V0 = Load_HI_16(v);
88   ConvertYUV444ToRGB(&Y0, &U0, &V0, R, G, B);
89 }
90 
91 // Convert 32 samples of YUV420 to R/G/B
YUV420ToRGB(const uint8_t * const y,const uint8_t * const u,const uint8_t * const v,__m128i * const R,__m128i * const G,__m128i * const B)92 static void YUV420ToRGB(const uint8_t* const y,
93                         const uint8_t* const u,
94                         const uint8_t* const v,
95                         __m128i* const R, __m128i* const G, __m128i* const B) {
96   const __m128i Y0 = Load_HI_16(y), U0 = Load_UV_HI_8(u), V0 = Load_UV_HI_8(v);
97   ConvertYUV444ToRGB(&Y0, &U0, &V0, R, G, B);
98 }
99 
100 // Pack R/G/B/A results into 32b output.
PackAndStore4(const __m128i * const R,const __m128i * const G,const __m128i * const B,const __m128i * const A,uint8_t * const dst)101 static WEBP_INLINE void PackAndStore4(const __m128i* const R,
102                                       const __m128i* const G,
103                                       const __m128i* const B,
104                                       const __m128i* const A,
105                                       uint8_t* const dst) {
106   const __m128i rb = _mm_packus_epi16(*R, *B);
107   const __m128i ga = _mm_packus_epi16(*G, *A);
108   const __m128i rg = _mm_unpacklo_epi8(rb, ga);
109   const __m128i ba = _mm_unpackhi_epi8(rb, ga);
110   const __m128i RGBA_lo = _mm_unpacklo_epi16(rg, ba);
111   const __m128i RGBA_hi = _mm_unpackhi_epi16(rg, ba);
112   _mm_storeu_si128((__m128i*)(dst +  0), RGBA_lo);
113   _mm_storeu_si128((__m128i*)(dst + 16), RGBA_hi);
114 }
115 
116 // Pack R/G/B/A results into 16b output.
PackAndStore4444(const __m128i * const R,const __m128i * const G,const __m128i * const B,const __m128i * const A,uint8_t * const dst)117 static WEBP_INLINE void PackAndStore4444(const __m128i* const R,
118                                          const __m128i* const G,
119                                          const __m128i* const B,
120                                          const __m128i* const A,
121                                          uint8_t* const dst) {
122 #if !defined(WEBP_SWAP_16BIT_CSP)
123   const __m128i rg0 = _mm_packus_epi16(*R, *G);
124   const __m128i ba0 = _mm_packus_epi16(*B, *A);
125 #else
126   const __m128i rg0 = _mm_packus_epi16(*B, *A);
127   const __m128i ba0 = _mm_packus_epi16(*R, *G);
128 #endif
129   const __m128i mask_0xf0 = _mm_set1_epi8(0xf0);
130   const __m128i rb1 = _mm_unpacklo_epi8(rg0, ba0);  // rbrbrbrbrb...
131   const __m128i ga1 = _mm_unpackhi_epi8(rg0, ba0);  // gagagagaga...
132   const __m128i rb2 = _mm_and_si128(rb1, mask_0xf0);
133   const __m128i ga2 = _mm_srli_epi16(_mm_and_si128(ga1, mask_0xf0), 4);
134   const __m128i rgba4444 = _mm_or_si128(rb2, ga2);
135   _mm_storeu_si128((__m128i*)dst, rgba4444);
136 }
137 
138 // Pack R/G/B results into 16b output.
PackAndStore565(const __m128i * const R,const __m128i * const G,const __m128i * const B,uint8_t * const dst)139 static WEBP_INLINE void PackAndStore565(const __m128i* const R,
140                                         const __m128i* const G,
141                                         const __m128i* const B,
142                                         uint8_t* const dst) {
143   const __m128i r0 = _mm_packus_epi16(*R, *R);
144   const __m128i g0 = _mm_packus_epi16(*G, *G);
145   const __m128i b0 = _mm_packus_epi16(*B, *B);
146   const __m128i r1 = _mm_and_si128(r0, _mm_set1_epi8(0xf8));
147   const __m128i b1 = _mm_and_si128(_mm_srli_epi16(b0, 3), _mm_set1_epi8(0x1f));
148   const __m128i g1 = _mm_srli_epi16(_mm_and_si128(g0, _mm_set1_epi8(0xe0)), 5);
149   const __m128i g2 = _mm_slli_epi16(_mm_and_si128(g0, _mm_set1_epi8(0x1c)), 3);
150   const __m128i rg = _mm_or_si128(r1, g1);
151   const __m128i gb = _mm_or_si128(g2, b1);
152 #if !defined(WEBP_SWAP_16BIT_CSP)
153   const __m128i rgb565 = _mm_unpacklo_epi8(rg, gb);
154 #else
155   const __m128i rgb565 = _mm_unpacklo_epi8(gb, rg);
156 #endif
157   _mm_storeu_si128((__m128i*)dst, rgb565);
158 }
159 
160 // Pack the planar buffers
161 // rrrr... rrrr... gggg... gggg... bbbb... bbbb....
162 // triplet by triplet in the output buffer rgb as rgbrgbrgbrgb ...
PlanarTo24b(__m128i * const in0,__m128i * const in1,__m128i * const in2,__m128i * const in3,__m128i * const in4,__m128i * const in5,uint8_t * const rgb)163 static WEBP_INLINE void PlanarTo24b(__m128i* const in0, __m128i* const in1,
164                                     __m128i* const in2, __m128i* const in3,
165                                     __m128i* const in4, __m128i* const in5,
166                                     uint8_t* const rgb) {
167   // The input is 6 registers of sixteen 8b but for the sake of explanation,
168   // let's take 6 registers of four 8b values.
169   // To pack, we will keep taking one every two 8b integer and move it
170   // around as follows:
171   // Input:
172   //   r0r1r2r3 | r4r5r6r7 | g0g1g2g3 | g4g5g6g7 | b0b1b2b3 | b4b5b6b7
173   // Split the 6 registers in two sets of 3 registers: the first set as the even
174   // 8b bytes, the second the odd ones:
175   //   r0r2r4r6 | g0g2g4g6 | b0b2b4b6 | r1r3r5r7 | g1g3g5g7 | b1b3b5b7
176   // Repeat the same permutations twice more:
177   //   r0r4g0g4 | b0b4r1r5 | g1g5b1b5 | r2r6g2g6 | b2b6r3r7 | g3g7b3b7
178   //   r0g0b0r1 | g1b1r2g2 | b2r3g3b3 | r4g4b4r5 | g5b5r6g6 | b6r7g7b7
179   VP8PlanarTo24b(in0, in1, in2, in3, in4, in5);
180 
181   _mm_storeu_si128((__m128i*)(rgb +  0), *in0);
182   _mm_storeu_si128((__m128i*)(rgb + 16), *in1);
183   _mm_storeu_si128((__m128i*)(rgb + 32), *in2);
184   _mm_storeu_si128((__m128i*)(rgb + 48), *in3);
185   _mm_storeu_si128((__m128i*)(rgb + 64), *in4);
186   _mm_storeu_si128((__m128i*)(rgb + 80), *in5);
187 }
188 
VP8YuvToRgba32(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst)189 void VP8YuvToRgba32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
190                     uint8_t* dst) {
191   const __m128i kAlpha = _mm_set1_epi16(255);
192   int n;
193   for (n = 0; n < 32; n += 8, dst += 32) {
194     __m128i R, G, B;
195     YUV444ToRGB(y + n, u + n, v + n, &R, &G, &B);
196     PackAndStore4(&R, &G, &B, &kAlpha, dst);
197   }
198 }
199 
VP8YuvToBgra32(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst)200 void VP8YuvToBgra32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
201                     uint8_t* dst) {
202   const __m128i kAlpha = _mm_set1_epi16(255);
203   int n;
204   for (n = 0; n < 32; n += 8, dst += 32) {
205     __m128i R, G, B;
206     YUV444ToRGB(y + n, u + n, v + n, &R, &G, &B);
207     PackAndStore4(&B, &G, &R, &kAlpha, dst);
208   }
209 }
210 
VP8YuvToArgb32(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst)211 void VP8YuvToArgb32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
212                     uint8_t* dst) {
213   const __m128i kAlpha = _mm_set1_epi16(255);
214   int n;
215   for (n = 0; n < 32; n += 8, dst += 32) {
216     __m128i R, G, B;
217     YUV444ToRGB(y + n, u + n, v + n, &R, &G, &B);
218     PackAndStore4(&kAlpha, &R, &G, &B, dst);
219   }
220 }
221 
VP8YuvToRgba444432(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst)222 void VP8YuvToRgba444432(const uint8_t* y, const uint8_t* u, const uint8_t* v,
223                         uint8_t* dst) {
224   const __m128i kAlpha = _mm_set1_epi16(255);
225   int n;
226   for (n = 0; n < 32; n += 8, dst += 16) {
227     __m128i R, G, B;
228     YUV444ToRGB(y + n, u + n, v + n, &R, &G, &B);
229     PackAndStore4444(&R, &G, &B, &kAlpha, dst);
230   }
231 }
232 
VP8YuvToRgb56532(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst)233 void VP8YuvToRgb56532(const uint8_t* y, const uint8_t* u, const uint8_t* v,
234                       uint8_t* dst) {
235   int n;
236   for (n = 0; n < 32; n += 8, dst += 16) {
237     __m128i R, G, B;
238     YUV444ToRGB(y + n, u + n, v + n, &R, &G, &B);
239     PackAndStore565(&R, &G, &B, dst);
240   }
241 }
242 
VP8YuvToRgb32(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst)243 void VP8YuvToRgb32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
244                    uint8_t* dst) {
245   __m128i R0, R1, R2, R3, G0, G1, G2, G3, B0, B1, B2, B3;
246   __m128i rgb0, rgb1, rgb2, rgb3, rgb4, rgb5;
247 
248   YUV444ToRGB(y + 0, u + 0, v + 0, &R0, &G0, &B0);
249   YUV444ToRGB(y + 8, u + 8, v + 8, &R1, &G1, &B1);
250   YUV444ToRGB(y + 16, u + 16, v + 16, &R2, &G2, &B2);
251   YUV444ToRGB(y + 24, u + 24, v + 24, &R3, &G3, &B3);
252 
253   // Cast to 8b and store as RRRRGGGGBBBB.
254   rgb0 = _mm_packus_epi16(R0, R1);
255   rgb1 = _mm_packus_epi16(R2, R3);
256   rgb2 = _mm_packus_epi16(G0, G1);
257   rgb3 = _mm_packus_epi16(G2, G3);
258   rgb4 = _mm_packus_epi16(B0, B1);
259   rgb5 = _mm_packus_epi16(B2, B3);
260 
261   // Pack as RGBRGBRGBRGB.
262   PlanarTo24b(&rgb0, &rgb1, &rgb2, &rgb3, &rgb4, &rgb5, dst);
263 }
264 
VP8YuvToBgr32(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst)265 void VP8YuvToBgr32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
266                    uint8_t* dst) {
267   __m128i R0, R1, R2, R3, G0, G1, G2, G3, B0, B1, B2, B3;
268   __m128i bgr0, bgr1, bgr2, bgr3, bgr4, bgr5;
269 
270   YUV444ToRGB(y +  0, u +  0, v +  0, &R0, &G0, &B0);
271   YUV444ToRGB(y +  8, u +  8, v +  8, &R1, &G1, &B1);
272   YUV444ToRGB(y + 16, u + 16, v + 16, &R2, &G2, &B2);
273   YUV444ToRGB(y + 24, u + 24, v + 24, &R3, &G3, &B3);
274 
275   // Cast to 8b and store as BBBBGGGGRRRR.
276   bgr0 = _mm_packus_epi16(B0, B1);
277   bgr1 = _mm_packus_epi16(B2, B3);
278   bgr2 = _mm_packus_epi16(G0, G1);
279   bgr3 = _mm_packus_epi16(G2, G3);
280   bgr4 = _mm_packus_epi16(R0, R1);
281   bgr5= _mm_packus_epi16(R2, R3);
282 
283   // Pack as BGRBGRBGRBGR.
284   PlanarTo24b(&bgr0, &bgr1, &bgr2, &bgr3, &bgr4, &bgr5, dst);
285 }
286 
287 //-----------------------------------------------------------------------------
288 // Arbitrary-length row conversion functions
289 
YuvToRgbaRow(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst,int len)290 static void YuvToRgbaRow(const uint8_t* y, const uint8_t* u, const uint8_t* v,
291                          uint8_t* dst, int len) {
292   const __m128i kAlpha = _mm_set1_epi16(255);
293   int n;
294   for (n = 0; n + 8 <= len; n += 8, dst += 32) {
295     __m128i R, G, B;
296     YUV420ToRGB(y, u, v, &R, &G, &B);
297     PackAndStore4(&R, &G, &B, &kAlpha, dst);
298     y += 8;
299     u += 4;
300     v += 4;
301   }
302   for (; n < len; ++n) {   // Finish off
303     VP8YuvToRgba(y[0], u[0], v[0], dst);
304     dst += 4;
305     y += 1;
306     u += (n & 1);
307     v += (n & 1);
308   }
309 }
310 
YuvToBgraRow(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst,int len)311 static void YuvToBgraRow(const uint8_t* y, const uint8_t* u, const uint8_t* v,
312                          uint8_t* dst, int len) {
313   const __m128i kAlpha = _mm_set1_epi16(255);
314   int n;
315   for (n = 0; n + 8 <= len; n += 8, dst += 32) {
316     __m128i R, G, B;
317     YUV420ToRGB(y, u, v, &R, &G, &B);
318     PackAndStore4(&B, &G, &R, &kAlpha, dst);
319     y += 8;
320     u += 4;
321     v += 4;
322   }
323   for (; n < len; ++n) {   // Finish off
324     VP8YuvToBgra(y[0], u[0], v[0], dst);
325     dst += 4;
326     y += 1;
327     u += (n & 1);
328     v += (n & 1);
329   }
330 }
331 
YuvToArgbRow(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst,int len)332 static void YuvToArgbRow(const uint8_t* y, const uint8_t* u, const uint8_t* v,
333                          uint8_t* dst, int len) {
334   const __m128i kAlpha = _mm_set1_epi16(255);
335   int n;
336   for (n = 0; n + 8 <= len; n += 8, dst += 32) {
337     __m128i R, G, B;
338     YUV420ToRGB(y, u, v, &R, &G, &B);
339     PackAndStore4(&kAlpha, &R, &G, &B, dst);
340     y += 8;
341     u += 4;
342     v += 4;
343   }
344   for (; n < len; ++n) {   // Finish off
345     VP8YuvToArgb(y[0], u[0], v[0], dst);
346     dst += 4;
347     y += 1;
348     u += (n & 1);
349     v += (n & 1);
350   }
351 }
352 
YuvToRgbRow(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst,int len)353 static void YuvToRgbRow(const uint8_t* y, const uint8_t* u, const uint8_t* v,
354                         uint8_t* dst, int len) {
355   int n;
356   for (n = 0; n + 32 <= len; n += 32, dst += 32 * 3) {
357     __m128i R0, R1, R2, R3, G0, G1, G2, G3, B0, B1, B2, B3;
358     __m128i rgb0, rgb1, rgb2, rgb3, rgb4, rgb5;
359 
360     YUV420ToRGB(y +  0, u +  0, v +  0, &R0, &G0, &B0);
361     YUV420ToRGB(y +  8, u +  4, v +  4, &R1, &G1, &B1);
362     YUV420ToRGB(y + 16, u +  8, v +  8, &R2, &G2, &B2);
363     YUV420ToRGB(y + 24, u + 12, v + 12, &R3, &G3, &B3);
364 
365     // Cast to 8b and store as RRRRGGGGBBBB.
366     rgb0 = _mm_packus_epi16(R0, R1);
367     rgb1 = _mm_packus_epi16(R2, R3);
368     rgb2 = _mm_packus_epi16(G0, G1);
369     rgb3 = _mm_packus_epi16(G2, G3);
370     rgb4 = _mm_packus_epi16(B0, B1);
371     rgb5 = _mm_packus_epi16(B2, B3);
372 
373     // Pack as RGBRGBRGBRGB.
374     PlanarTo24b(&rgb0, &rgb1, &rgb2, &rgb3, &rgb4, &rgb5, dst);
375 
376     y += 32;
377     u += 16;
378     v += 16;
379   }
380   for (; n < len; ++n) {   // Finish off
381     VP8YuvToRgb(y[0], u[0], v[0], dst);
382     dst += 3;
383     y += 1;
384     u += (n & 1);
385     v += (n & 1);
386   }
387 }
388 
YuvToBgrRow(const uint8_t * y,const uint8_t * u,const uint8_t * v,uint8_t * dst,int len)389 static void YuvToBgrRow(const uint8_t* y, const uint8_t* u, const uint8_t* v,
390                         uint8_t* dst, int len) {
391   int n;
392   for (n = 0; n + 32 <= len; n += 32, dst += 32 * 3) {
393     __m128i R0, R1, R2, R3, G0, G1, G2, G3, B0, B1, B2, B3;
394     __m128i bgr0, bgr1, bgr2, bgr3, bgr4, bgr5;
395 
396     YUV420ToRGB(y +  0, u +  0, v +  0, &R0, &G0, &B0);
397     YUV420ToRGB(y +  8, u +  4, v +  4, &R1, &G1, &B1);
398     YUV420ToRGB(y + 16, u +  8, v +  8, &R2, &G2, &B2);
399     YUV420ToRGB(y + 24, u + 12, v + 12, &R3, &G3, &B3);
400 
401     // Cast to 8b and store as BBBBGGGGRRRR.
402     bgr0 = _mm_packus_epi16(B0, B1);
403     bgr1 = _mm_packus_epi16(B2, B3);
404     bgr2 = _mm_packus_epi16(G0, G1);
405     bgr3 = _mm_packus_epi16(G2, G3);
406     bgr4 = _mm_packus_epi16(R0, R1);
407     bgr5 = _mm_packus_epi16(R2, R3);
408 
409     // Pack as BGRBGRBGRBGR.
410     PlanarTo24b(&bgr0, &bgr1, &bgr2, &bgr3, &bgr4, &bgr5, dst);
411 
412     y += 32;
413     u += 16;
414     v += 16;
415   }
416   for (; n < len; ++n) {   // Finish off
417     VP8YuvToBgr(y[0], u[0], v[0], dst);
418     dst += 3;
419     y += 1;
420     u += (n & 1);
421     v += (n & 1);
422   }
423 }
424 
425 //------------------------------------------------------------------------------
426 // Entry point
427 
428 extern void WebPInitSamplersSSE2(void);
429 
WebPInitSamplersSSE2(void)430 WEBP_TSAN_IGNORE_FUNCTION void WebPInitSamplersSSE2(void) {
431   WebPSamplers[MODE_RGB]  = YuvToRgbRow;
432   WebPSamplers[MODE_RGBA] = YuvToRgbaRow;
433   WebPSamplers[MODE_BGR]  = YuvToBgrRow;
434   WebPSamplers[MODE_BGRA] = YuvToBgraRow;
435   WebPSamplers[MODE_ARGB] = YuvToArgbRow;
436 }
437 
438 //------------------------------------------------------------------------------
439 // RGB24/32 -> YUV converters
440 
441 // Load eight 16b-words from *src.
442 #define LOAD_16(src) _mm_loadu_si128((const __m128i*)(src))
443 // Store either 16b-words into *dst
444 #define STORE_16(V, dst) _mm_storeu_si128((__m128i*)(dst), (V))
445 
446 // Function that inserts a value of the second half of the in buffer in between
447 // every two char of the first half.
RGB24PackedToPlanarHelper(const __m128i * const in,__m128i * const out)448 static WEBP_INLINE void RGB24PackedToPlanarHelper(
449     const __m128i* const in /*in[6]*/, __m128i* const out /*out[6]*/) {
450   out[0] = _mm_unpacklo_epi8(in[0], in[3]);
451   out[1] = _mm_unpackhi_epi8(in[0], in[3]);
452   out[2] = _mm_unpacklo_epi8(in[1], in[4]);
453   out[3] = _mm_unpackhi_epi8(in[1], in[4]);
454   out[4] = _mm_unpacklo_epi8(in[2], in[5]);
455   out[5] = _mm_unpackhi_epi8(in[2], in[5]);
456 }
457 
458 // Unpack the 8b input rgbrgbrgbrgb ... as contiguous registers:
459 // rrrr... rrrr... gggg... gggg... bbbb... bbbb....
460 // Similar to PlanarTo24bHelper(), but in reverse order.
RGB24PackedToPlanar(const uint8_t * const rgb,__m128i * const out)461 static WEBP_INLINE void RGB24PackedToPlanar(const uint8_t* const rgb,
462                                             __m128i* const out /*out[6]*/) {
463   __m128i tmp[6];
464   tmp[0] = _mm_loadu_si128((const __m128i*)(rgb +  0));
465   tmp[1] = _mm_loadu_si128((const __m128i*)(rgb + 16));
466   tmp[2] = _mm_loadu_si128((const __m128i*)(rgb + 32));
467   tmp[3] = _mm_loadu_si128((const __m128i*)(rgb + 48));
468   tmp[4] = _mm_loadu_si128((const __m128i*)(rgb + 64));
469   tmp[5] = _mm_loadu_si128((const __m128i*)(rgb + 80));
470 
471   RGB24PackedToPlanarHelper(tmp, out);
472   RGB24PackedToPlanarHelper(out, tmp);
473   RGB24PackedToPlanarHelper(tmp, out);
474   RGB24PackedToPlanarHelper(out, tmp);
475   RGB24PackedToPlanarHelper(tmp, out);
476 }
477 
478 // Convert 8 packed ARGB to r[], g[], b[]
RGB32PackedToPlanar(const uint32_t * const argb,__m128i * const rgb)479 static WEBP_INLINE void RGB32PackedToPlanar(const uint32_t* const argb,
480                                             __m128i* const rgb /*in[6]*/) {
481   const __m128i zero = _mm_setzero_si128();
482   __m128i a0 = LOAD_16(argb + 0);
483   __m128i a1 = LOAD_16(argb + 4);
484   __m128i a2 = LOAD_16(argb + 8);
485   __m128i a3 = LOAD_16(argb + 12);
486   VP8L32bToPlanar(&a0, &a1, &a2, &a3);
487   rgb[0] = _mm_unpacklo_epi8(a1, zero);
488   rgb[1] = _mm_unpackhi_epi8(a1, zero);
489   rgb[2] = _mm_unpacklo_epi8(a2, zero);
490   rgb[3] = _mm_unpackhi_epi8(a2, zero);
491   rgb[4] = _mm_unpacklo_epi8(a3, zero);
492   rgb[5] = _mm_unpackhi_epi8(a3, zero);
493 }
494 
495 // This macro computes (RG * MULT_RG + GB * MULT_GB + ROUNDER) >> DESCALE_FIX
496 // It's a macro and not a function because we need to use immediate values with
497 // srai_epi32, e.g.
498 #define TRANSFORM(RG_LO, RG_HI, GB_LO, GB_HI, MULT_RG, MULT_GB, \
499                   ROUNDER, DESCALE_FIX, OUT) do {               \
500   const __m128i V0_lo = _mm_madd_epi16(RG_LO, MULT_RG);         \
501   const __m128i V0_hi = _mm_madd_epi16(RG_HI, MULT_RG);         \
502   const __m128i V1_lo = _mm_madd_epi16(GB_LO, MULT_GB);         \
503   const __m128i V1_hi = _mm_madd_epi16(GB_HI, MULT_GB);         \
504   const __m128i V2_lo = _mm_add_epi32(V0_lo, V1_lo);            \
505   const __m128i V2_hi = _mm_add_epi32(V0_hi, V1_hi);            \
506   const __m128i V3_lo = _mm_add_epi32(V2_lo, ROUNDER);          \
507   const __m128i V3_hi = _mm_add_epi32(V2_hi, ROUNDER);          \
508   const __m128i V5_lo = _mm_srai_epi32(V3_lo, DESCALE_FIX);     \
509   const __m128i V5_hi = _mm_srai_epi32(V3_hi, DESCALE_FIX);     \
510   (OUT) = _mm_packs_epi32(V5_lo, V5_hi);                        \
511 } while (0)
512 
513 #define MK_CST_16(A, B) _mm_set_epi16((B), (A), (B), (A), (B), (A), (B), (A))
ConvertRGBToY(const __m128i * const R,const __m128i * const G,const __m128i * const B,__m128i * const Y)514 static WEBP_INLINE void ConvertRGBToY(const __m128i* const R,
515                                       const __m128i* const G,
516                                       const __m128i* const B,
517                                       __m128i* const Y) {
518   const __m128i kRG_y = MK_CST_16(16839, 33059 - 16384);
519   const __m128i kGB_y = MK_CST_16(16384, 6420);
520   const __m128i kHALF_Y = _mm_set1_epi32((16 << YUV_FIX) + YUV_HALF);
521 
522   const __m128i RG_lo = _mm_unpacklo_epi16(*R, *G);
523   const __m128i RG_hi = _mm_unpackhi_epi16(*R, *G);
524   const __m128i GB_lo = _mm_unpacklo_epi16(*G, *B);
525   const __m128i GB_hi = _mm_unpackhi_epi16(*G, *B);
526   TRANSFORM(RG_lo, RG_hi, GB_lo, GB_hi, kRG_y, kGB_y, kHALF_Y, YUV_FIX, *Y);
527 }
528 
ConvertRGBToUV(const __m128i * const R,const __m128i * const G,const __m128i * const B,__m128i * const U,__m128i * const V)529 static WEBP_INLINE void ConvertRGBToUV(const __m128i* const R,
530                                        const __m128i* const G,
531                                        const __m128i* const B,
532                                        __m128i* const U, __m128i* const V) {
533   const __m128i kRG_u = MK_CST_16(-9719, -19081);
534   const __m128i kGB_u = MK_CST_16(0, 28800);
535   const __m128i kRG_v = MK_CST_16(28800, 0);
536   const __m128i kGB_v = MK_CST_16(-24116, -4684);
537   const __m128i kHALF_UV = _mm_set1_epi32(((128 << YUV_FIX) + YUV_HALF) << 2);
538 
539   const __m128i RG_lo = _mm_unpacklo_epi16(*R, *G);
540   const __m128i RG_hi = _mm_unpackhi_epi16(*R, *G);
541   const __m128i GB_lo = _mm_unpacklo_epi16(*G, *B);
542   const __m128i GB_hi = _mm_unpackhi_epi16(*G, *B);
543   TRANSFORM(RG_lo, RG_hi, GB_lo, GB_hi, kRG_u, kGB_u,
544             kHALF_UV, YUV_FIX + 2, *U);
545   TRANSFORM(RG_lo, RG_hi, GB_lo, GB_hi, kRG_v, kGB_v,
546             kHALF_UV, YUV_FIX + 2, *V);
547 }
548 
549 #undef MK_CST_16
550 #undef TRANSFORM
551 
ConvertRGB24ToY(const uint8_t * rgb,uint8_t * y,int width)552 static void ConvertRGB24ToY(const uint8_t* rgb, uint8_t* y, int width) {
553   const int max_width = width & ~31;
554   int i;
555   for (i = 0; i < max_width; rgb += 3 * 16 * 2) {
556     __m128i rgb_plane[6];
557     int j;
558 
559     RGB24PackedToPlanar(rgb, rgb_plane);
560 
561     for (j = 0; j < 2; ++j, i += 16) {
562       const __m128i zero = _mm_setzero_si128();
563       __m128i r, g, b, Y0, Y1;
564 
565       // Convert to 16-bit Y.
566       r = _mm_unpacklo_epi8(rgb_plane[0 + j], zero);
567       g = _mm_unpacklo_epi8(rgb_plane[2 + j], zero);
568       b = _mm_unpacklo_epi8(rgb_plane[4 + j], zero);
569       ConvertRGBToY(&r, &g, &b, &Y0);
570 
571       // Convert to 16-bit Y.
572       r = _mm_unpackhi_epi8(rgb_plane[0 + j], zero);
573       g = _mm_unpackhi_epi8(rgb_plane[2 + j], zero);
574       b = _mm_unpackhi_epi8(rgb_plane[4 + j], zero);
575       ConvertRGBToY(&r, &g, &b, &Y1);
576 
577       // Cast to 8-bit and store.
578       STORE_16(_mm_packus_epi16(Y0, Y1), y + i);
579     }
580   }
581   for (; i < width; ++i, rgb += 3) {   // left-over
582     y[i] = VP8RGBToY(rgb[0], rgb[1], rgb[2], YUV_HALF);
583   }
584 }
585 
ConvertBGR24ToY(const uint8_t * bgr,uint8_t * y,int width)586 static void ConvertBGR24ToY(const uint8_t* bgr, uint8_t* y, int width) {
587   const int max_width = width & ~31;
588   int i;
589   for (i = 0; i < max_width; bgr += 3 * 16 * 2) {
590     __m128i bgr_plane[6];
591     int j;
592 
593     RGB24PackedToPlanar(bgr, bgr_plane);
594 
595     for (j = 0; j < 2; ++j, i += 16) {
596       const __m128i zero = _mm_setzero_si128();
597       __m128i r, g, b, Y0, Y1;
598 
599       // Convert to 16-bit Y.
600       b = _mm_unpacklo_epi8(bgr_plane[0 + j], zero);
601       g = _mm_unpacklo_epi8(bgr_plane[2 + j], zero);
602       r = _mm_unpacklo_epi8(bgr_plane[4 + j], zero);
603       ConvertRGBToY(&r, &g, &b, &Y0);
604 
605       // Convert to 16-bit Y.
606       b = _mm_unpackhi_epi8(bgr_plane[0 + j], zero);
607       g = _mm_unpackhi_epi8(bgr_plane[2 + j], zero);
608       r = _mm_unpackhi_epi8(bgr_plane[4 + j], zero);
609       ConvertRGBToY(&r, &g, &b, &Y1);
610 
611       // Cast to 8-bit and store.
612       STORE_16(_mm_packus_epi16(Y0, Y1), y + i);
613     }
614   }
615   for (; i < width; ++i, bgr += 3) {  // left-over
616     y[i] = VP8RGBToY(bgr[2], bgr[1], bgr[0], YUV_HALF);
617   }
618 }
619 
ConvertARGBToY(const uint32_t * argb,uint8_t * y,int width)620 static void ConvertARGBToY(const uint32_t* argb, uint8_t* y, int width) {
621   const int max_width = width & ~15;
622   int i;
623   for (i = 0; i < max_width; i += 16) {
624     __m128i Y0, Y1, rgb[6];
625     RGB32PackedToPlanar(&argb[i], rgb);
626     ConvertRGBToY(&rgb[0], &rgb[2], &rgb[4], &Y0);
627     ConvertRGBToY(&rgb[1], &rgb[3], &rgb[5], &Y1);
628     STORE_16(_mm_packus_epi16(Y0, Y1), y + i);
629   }
630   for (; i < width; ++i) {   // left-over
631     const uint32_t p = argb[i];
632     y[i] = VP8RGBToY((p >> 16) & 0xff, (p >> 8) & 0xff, (p >>  0) & 0xff,
633                      YUV_HALF);
634   }
635 }
636 
637 // Horizontal add (doubled) of two 16b values, result is 16b.
638 // in: A | B | C | D | ... -> out: 2*(A+B) | 2*(C+D) | ...
HorizontalAddPack(const __m128i * const A,const __m128i * const B,__m128i * const out)639 static void HorizontalAddPack(const __m128i* const A, const __m128i* const B,
640                               __m128i* const out) {
641   const __m128i k2 = _mm_set1_epi16(2);
642   const __m128i C = _mm_madd_epi16(*A, k2);
643   const __m128i D = _mm_madd_epi16(*B, k2);
644   *out = _mm_packs_epi32(C, D);
645 }
646 
ConvertARGBToUV(const uint32_t * argb,uint8_t * u,uint8_t * v,int src_width,int do_store)647 static void ConvertARGBToUV(const uint32_t* argb, uint8_t* u, uint8_t* v,
648                             int src_width, int do_store) {
649   const int max_width = src_width & ~31;
650   int i;
651   for (i = 0; i < max_width; i += 32, u += 16, v += 16) {
652     __m128i rgb[6], U0, V0, U1, V1;
653     RGB32PackedToPlanar(&argb[i], rgb);
654     HorizontalAddPack(&rgb[0], &rgb[1], &rgb[0]);
655     HorizontalAddPack(&rgb[2], &rgb[3], &rgb[2]);
656     HorizontalAddPack(&rgb[4], &rgb[5], &rgb[4]);
657     ConvertRGBToUV(&rgb[0], &rgb[2], &rgb[4], &U0, &V0);
658 
659     RGB32PackedToPlanar(&argb[i + 16], rgb);
660     HorizontalAddPack(&rgb[0], &rgb[1], &rgb[0]);
661     HorizontalAddPack(&rgb[2], &rgb[3], &rgb[2]);
662     HorizontalAddPack(&rgb[4], &rgb[5], &rgb[4]);
663     ConvertRGBToUV(&rgb[0], &rgb[2], &rgb[4], &U1, &V1);
664 
665     U0 = _mm_packus_epi16(U0, U1);
666     V0 = _mm_packus_epi16(V0, V1);
667     if (!do_store) {
668       const __m128i prev_u = LOAD_16(u);
669       const __m128i prev_v = LOAD_16(v);
670       U0 = _mm_avg_epu8(U0, prev_u);
671       V0 = _mm_avg_epu8(V0, prev_v);
672     }
673     STORE_16(U0, u);
674     STORE_16(V0, v);
675   }
676   if (i < src_width) {  // left-over
677     WebPConvertARGBToUV_C(argb + i, u, v, src_width - i, do_store);
678   }
679 }
680 
681 // Convert 16 packed ARGB 16b-values to r[], g[], b[]
RGBA32PackedToPlanar_16b(const uint16_t * const rgbx,__m128i * const r,__m128i * const g,__m128i * const b)682 static WEBP_INLINE void RGBA32PackedToPlanar_16b(const uint16_t* const rgbx,
683                                                  __m128i* const r,
684                                                  __m128i* const g,
685                                                  __m128i* const b) {
686   const __m128i in0 = LOAD_16(rgbx +  0);  // r0 | g0 | b0 |x| r1 | g1 | b1 |x
687   const __m128i in1 = LOAD_16(rgbx +  8);  // r2 | g2 | b2 |x| r3 | g3 | b3 |x
688   const __m128i in2 = LOAD_16(rgbx + 16);  // r4 | ...
689   const __m128i in3 = LOAD_16(rgbx + 24);  // r6 | ...
690   // column-wise transpose
691   const __m128i A0 = _mm_unpacklo_epi16(in0, in1);
692   const __m128i A1 = _mm_unpackhi_epi16(in0, in1);
693   const __m128i A2 = _mm_unpacklo_epi16(in2, in3);
694   const __m128i A3 = _mm_unpackhi_epi16(in2, in3);
695   const __m128i B0 = _mm_unpacklo_epi16(A0, A1);  // r0 r1 r2 r3 | g0 g1 ..
696   const __m128i B1 = _mm_unpackhi_epi16(A0, A1);  // b0 b1 b2 b3 | x x x x
697   const __m128i B2 = _mm_unpacklo_epi16(A2, A3);  // r4 r5 r6 r7 | g4 g5 ..
698   const __m128i B3 = _mm_unpackhi_epi16(A2, A3);  // b4 b5 b6 b7 | x x x x
699   *r = _mm_unpacklo_epi64(B0, B2);
700   *g = _mm_unpackhi_epi64(B0, B2);
701   *b = _mm_unpacklo_epi64(B1, B3);
702 }
703 
ConvertRGBA32ToUV(const uint16_t * rgb,uint8_t * u,uint8_t * v,int width)704 static void ConvertRGBA32ToUV(const uint16_t* rgb,
705                               uint8_t* u, uint8_t* v, int width) {
706   const int max_width = width & ~15;
707   const uint16_t* const last_rgb = rgb + 4 * max_width;
708   while (rgb < last_rgb) {
709     __m128i r, g, b, U0, V0, U1, V1;
710     RGBA32PackedToPlanar_16b(rgb +  0, &r, &g, &b);
711     ConvertRGBToUV(&r, &g, &b, &U0, &V0);
712     RGBA32PackedToPlanar_16b(rgb + 32, &r, &g, &b);
713     ConvertRGBToUV(&r, &g, &b, &U1, &V1);
714     STORE_16(_mm_packus_epi16(U0, U1), u);
715     STORE_16(_mm_packus_epi16(V0, V1), v);
716     u += 16;
717     v += 16;
718     rgb += 2 * 32;
719   }
720   if (max_width < width) {  // left-over
721     WebPConvertRGBA32ToUV_C(rgb, u, v, width - max_width);
722   }
723 }
724 
725 //------------------------------------------------------------------------------
726 
727 extern void WebPInitConvertARGBToYUVSSE2(void);
728 
WebPInitConvertARGBToYUVSSE2(void)729 WEBP_TSAN_IGNORE_FUNCTION void WebPInitConvertARGBToYUVSSE2(void) {
730   WebPConvertARGBToY = ConvertARGBToY;
731   WebPConvertARGBToUV = ConvertARGBToUV;
732 
733   WebPConvertRGB24ToY = ConvertRGB24ToY;
734   WebPConvertBGR24ToY = ConvertBGR24ToY;
735 
736   WebPConvertRGBA32ToUV = ConvertRGBA32ToUV;
737 }
738 
739 //------------------------------------------------------------------------------
740 
741 #define MAX_Y ((1 << 10) - 1)    // 10b precision over 16b-arithmetic
clip_y(int v)742 static uint16_t clip_y(int v) {
743   return (v < 0) ? 0 : (v > MAX_Y) ? MAX_Y : (uint16_t)v;
744 }
745 
SharpYUVUpdateY_SSE2(const uint16_t * ref,const uint16_t * src,uint16_t * dst,int len)746 static uint64_t SharpYUVUpdateY_SSE2(const uint16_t* ref, const uint16_t* src,
747                                      uint16_t* dst, int len) {
748   uint64_t diff = 0;
749   uint32_t tmp[4];
750   int i;
751   const __m128i zero = _mm_setzero_si128();
752   const __m128i max = _mm_set1_epi16(MAX_Y);
753   const __m128i one = _mm_set1_epi16(1);
754   __m128i sum = zero;
755 
756   for (i = 0; i + 8 <= len; i += 8) {
757     const __m128i A = _mm_loadu_si128((const __m128i*)(ref + i));
758     const __m128i B = _mm_loadu_si128((const __m128i*)(src + i));
759     const __m128i C = _mm_loadu_si128((const __m128i*)(dst + i));
760     const __m128i D = _mm_sub_epi16(A, B);       // diff_y
761     const __m128i E = _mm_cmpgt_epi16(zero, D);  // sign (-1 or 0)
762     const __m128i F = _mm_add_epi16(C, D);       // new_y
763     const __m128i G = _mm_or_si128(E, one);      // -1 or 1
764     const __m128i H = _mm_max_epi16(_mm_min_epi16(F, max), zero);
765     const __m128i I = _mm_madd_epi16(D, G);      // sum(abs(...))
766     _mm_storeu_si128((__m128i*)(dst + i), H);
767     sum = _mm_add_epi32(sum, I);
768   }
769   _mm_storeu_si128((__m128i*)tmp, sum);
770   diff = tmp[3] + tmp[2] + tmp[1] + tmp[0];
771   for (; i < len; ++i) {
772     const int diff_y = ref[i] - src[i];
773     const int new_y = (int)dst[i] + diff_y;
774     dst[i] = clip_y(new_y);
775     diff += (uint64_t)abs(diff_y);
776   }
777   return diff;
778 }
779 
SharpYUVUpdateRGB_SSE2(const int16_t * ref,const int16_t * src,int16_t * dst,int len)780 static void SharpYUVUpdateRGB_SSE2(const int16_t* ref, const int16_t* src,
781                                    int16_t* dst, int len) {
782   int i = 0;
783   for (i = 0; i + 8 <= len; i += 8) {
784     const __m128i A = _mm_loadu_si128((const __m128i*)(ref + i));
785     const __m128i B = _mm_loadu_si128((const __m128i*)(src + i));
786     const __m128i C = _mm_loadu_si128((const __m128i*)(dst + i));
787     const __m128i D = _mm_sub_epi16(A, B);   // diff_uv
788     const __m128i E = _mm_add_epi16(C, D);   // new_uv
789     _mm_storeu_si128((__m128i*)(dst + i), E);
790   }
791   for (; i < len; ++i) {
792     const int diff_uv = ref[i] - src[i];
793     dst[i] += diff_uv;
794   }
795 }
796 
SharpYUVFilterRow_SSE2(const int16_t * A,const int16_t * B,int len,const uint16_t * best_y,uint16_t * out)797 static void SharpYUVFilterRow_SSE2(const int16_t* A, const int16_t* B, int len,
798                                    const uint16_t* best_y, uint16_t* out) {
799   int i;
800   const __m128i kCst8 = _mm_set1_epi16(8);
801   const __m128i max = _mm_set1_epi16(MAX_Y);
802   const __m128i zero = _mm_setzero_si128();
803   for (i = 0; i + 8 <= len; i += 8) {
804     const __m128i a0 = _mm_loadu_si128((const __m128i*)(A + i + 0));
805     const __m128i a1 = _mm_loadu_si128((const __m128i*)(A + i + 1));
806     const __m128i b0 = _mm_loadu_si128((const __m128i*)(B + i + 0));
807     const __m128i b1 = _mm_loadu_si128((const __m128i*)(B + i + 1));
808     const __m128i a0b1 = _mm_add_epi16(a0, b1);
809     const __m128i a1b0 = _mm_add_epi16(a1, b0);
810     const __m128i a0a1b0b1 = _mm_add_epi16(a0b1, a1b0);  // A0+A1+B0+B1
811     const __m128i a0a1b0b1_8 = _mm_add_epi16(a0a1b0b1, kCst8);
812     const __m128i a0b1_2 = _mm_add_epi16(a0b1, a0b1);    // 2*(A0+B1)
813     const __m128i a1b0_2 = _mm_add_epi16(a1b0, a1b0);    // 2*(A1+B0)
814     const __m128i c0 = _mm_srai_epi16(_mm_add_epi16(a0b1_2, a0a1b0b1_8), 3);
815     const __m128i c1 = _mm_srai_epi16(_mm_add_epi16(a1b0_2, a0a1b0b1_8), 3);
816     const __m128i d0 = _mm_add_epi16(c1, a0);
817     const __m128i d1 = _mm_add_epi16(c0, a1);
818     const __m128i e0 = _mm_srai_epi16(d0, 1);
819     const __m128i e1 = _mm_srai_epi16(d1, 1);
820     const __m128i f0 = _mm_unpacklo_epi16(e0, e1);
821     const __m128i f1 = _mm_unpackhi_epi16(e0, e1);
822     const __m128i g0 = _mm_loadu_si128((const __m128i*)(best_y + 2 * i + 0));
823     const __m128i g1 = _mm_loadu_si128((const __m128i*)(best_y + 2 * i + 8));
824     const __m128i h0 = _mm_add_epi16(g0, f0);
825     const __m128i h1 = _mm_add_epi16(g1, f1);
826     const __m128i i0 = _mm_max_epi16(_mm_min_epi16(h0, max), zero);
827     const __m128i i1 = _mm_max_epi16(_mm_min_epi16(h1, max), zero);
828     _mm_storeu_si128((__m128i*)(out + 2 * i + 0), i0);
829     _mm_storeu_si128((__m128i*)(out + 2 * i + 8), i1);
830   }
831   for (; i < len; ++i) {
832     //   (9 * A0 + 3 * A1 + 3 * B0 + B1 + 8) >> 4 =
833     // = (8 * A0 + 2 * (A1 + B0) + (A0 + A1 + B0 + B1 + 8)) >> 4
834     // We reuse the common sub-expressions.
835     const int a0b1 = A[i + 0] + B[i + 1];
836     const int a1b0 = A[i + 1] + B[i + 0];
837     const int a0a1b0b1 = a0b1 + a1b0 + 8;
838     const int v0 = (8 * A[i + 0] + 2 * a1b0 + a0a1b0b1) >> 4;
839     const int v1 = (8 * A[i + 1] + 2 * a0b1 + a0a1b0b1) >> 4;
840     out[2 * i + 0] = clip_y(best_y[2 * i + 0] + v0);
841     out[2 * i + 1] = clip_y(best_y[2 * i + 1] + v1);
842   }
843 }
844 
845 #undef MAX_Y
846 
847 //------------------------------------------------------------------------------
848 
849 extern void WebPInitSharpYUVSSE2(void);
850 
WebPInitSharpYUVSSE2(void)851 WEBP_TSAN_IGNORE_FUNCTION void WebPInitSharpYUVSSE2(void) {
852   WebPSharpYUVUpdateY = SharpYUVUpdateY_SSE2;
853   WebPSharpYUVUpdateRGB = SharpYUVUpdateRGB_SSE2;
854   WebPSharpYUVFilterRow = SharpYUVFilterRow_SSE2;
855 }
856 
857 #else  // !WEBP_USE_SSE2
858 
859 WEBP_DSP_INIT_STUB(WebPInitSamplersSSE2)
860 WEBP_DSP_INIT_STUB(WebPInitConvertARGBToYUVSSE2)
861 WEBP_DSP_INIT_STUB(WebPInitSharpYUVSSE2)
862 
863 #endif  // WEBP_USE_SSE2
864