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// Utilities for processing transparent channel.
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#include "src/dsp/dsp.h"
15
16#if defined(WEBP_USE_SSE2)
17#include <emmintrin.h>
18
19//------------------------------------------------------------------------------
20
21static int DispatchAlpha_SSE2(const uint8_t* alpha, int alpha_stride,
22 int width, int height,
23 uint8_t* dst, int dst_stride) {
24 // alpha_and stores an 'and' operation of all the alpha[] values. The final
25 // value is not 0xff if any of the alpha[] is not equal to 0xff.
26 uint32_t alpha_and = 0xff;
27 int i, j;
28 const __m128i zero = _mm_setzero_si128();
29 const __m128i rgb_mask = _mm_set1_epi32(0xffffff00u); // to preserve RGB
30 const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);
31 __m128i all_alphas = all_0xff;
32
33 // We must be able to access 3 extra bytes after the last written byte
34 // 'dst[4 * width - 4]', because we don't know if alpha is the first or the
35 // last byte of the quadruplet.
36 const int limit = (width - 1) & ~7;
37
38 for (j = 0; j < height; ++j) {
39 __m128i* out = (__m128i*)dst;
40 for (i = 0; i < limit; i += 8) {
41 // load 8 alpha bytes
42 const __m128i a0 = _mm_loadl_epi64((const __m128i*)&alpha[i]);
43 const __m128i a1 = _mm_unpacklo_epi8(a0, zero);
44 const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);
45 const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);
46 // load 8 dst pixels (32 bytes)
47 const __m128i b0_lo = _mm_loadu_si128(out + 0);
48 const __m128i b0_hi = _mm_loadu_si128(out + 1);
49 // mask dst alpha values
50 const __m128i b1_lo = _mm_and_si128(b0_lo, rgb_mask);
51 const __m128i b1_hi = _mm_and_si128(b0_hi, rgb_mask);
52 // combine
53 const __m128i b2_lo = _mm_or_si128(b1_lo, a2_lo);
54 const __m128i b2_hi = _mm_or_si128(b1_hi, a2_hi);
55 // store
56 _mm_storeu_si128(out + 0, b2_lo);
57 _mm_storeu_si128(out + 1, b2_hi);
58 // accumulate eight alpha 'and' in parallel
59 all_alphas = _mm_and_si128(all_alphas, a0);
60 out += 2;
61 }
62 for (; i < width; ++i) {
63 const uint32_t alpha_value = alpha[i];
64 dst[4 * i] = alpha_value;
65 alpha_and &= alpha_value;
66 }
67 alpha += alpha_stride;
68 dst += dst_stride;
69 }
70 // Combine the eight alpha 'and' into a 8-bit mask.
71 alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));
72 return (alpha_and != 0xff);
73}
74
75static void DispatchAlphaToGreen_SSE2(const uint8_t* alpha, int alpha_stride,
76 int width, int height,
77 uint32_t* dst, int dst_stride) {
78 int i, j;
79 const __m128i zero = _mm_setzero_si128();
80 const int limit = width & ~15;
81 for (j = 0; j < height; ++j) {
82 for (i = 0; i < limit; i += 16) { // process 16 alpha bytes
83 const __m128i a0 = _mm_loadu_si128((const __m128i*)&alpha[i]);
84 const __m128i a1 = _mm_unpacklo_epi8(zero, a0); // note the 'zero' first!
85 const __m128i b1 = _mm_unpackhi_epi8(zero, a0);
86 const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);
87 const __m128i b2_lo = _mm_unpacklo_epi16(b1, zero);
88 const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);
89 const __m128i b2_hi = _mm_unpackhi_epi16(b1, zero);
90 _mm_storeu_si128((__m128i*)&dst[i + 0], a2_lo);
91 _mm_storeu_si128((__m128i*)&dst[i + 4], a2_hi);
92 _mm_storeu_si128((__m128i*)&dst[i + 8], b2_lo);
93 _mm_storeu_si128((__m128i*)&dst[i + 12], b2_hi);
94 }
95 for (; i < width; ++i) dst[i] = alpha[i] << 8;
96 alpha += alpha_stride;
97 dst += dst_stride;
98 }
99}
100
101static int ExtractAlpha_SSE2(const uint8_t* argb, int argb_stride,
102 int width, int height,
103 uint8_t* alpha, int alpha_stride) {
104 // alpha_and stores an 'and' operation of all the alpha[] values. The final
105 // value is not 0xff if any of the alpha[] is not equal to 0xff.
106 uint32_t alpha_and = 0xff;
107 int i, j;
108 const __m128i a_mask = _mm_set1_epi32(0xffu); // to preserve alpha
109 const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);
110 __m128i all_alphas = all_0xff;
111
112 // We must be able to access 3 extra bytes after the last written byte
113 // 'src[4 * width - 4]', because we don't know if alpha is the first or the
114 // last byte of the quadruplet.
115 const int limit = (width - 1) & ~7;
116
117 for (j = 0; j < height; ++j) {
118 const __m128i* src = (const __m128i*)argb;
119 for (i = 0; i < limit; i += 8) {
120 // load 32 argb bytes
121 const __m128i a0 = _mm_loadu_si128(src + 0);
122 const __m128i a1 = _mm_loadu_si128(src + 1);
123 const __m128i b0 = _mm_and_si128(a0, a_mask);
124 const __m128i b1 = _mm_and_si128(a1, a_mask);
125 const __m128i c0 = _mm_packs_epi32(b0, b1);
126 const __m128i d0 = _mm_packus_epi16(c0, c0);
127 // store
128 _mm_storel_epi64((__m128i*)&alpha[i], d0);
129 // accumulate eight alpha 'and' in parallel
130 all_alphas = _mm_and_si128(all_alphas, d0);
131 src += 2;
132 }
133 for (; i < width; ++i) {
134 const uint32_t alpha_value = argb[4 * i];
135 alpha[i] = alpha_value;
136 alpha_and &= alpha_value;
137 }
138 argb += argb_stride;
139 alpha += alpha_stride;
140 }
141 // Combine the eight alpha 'and' into a 8-bit mask.
142 alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));
143 return (alpha_and == 0xff);
144}
145
146//------------------------------------------------------------------------------
147// Non-dither premultiplied modes
148
149#define MULTIPLIER(a) ((a) * 0x8081)
150#define PREMULTIPLY(x, m) (((x) * (m)) >> 23)
151
152// We can't use a 'const int' for the SHUFFLE value, because it has to be an
153// immediate in the _mm_shufflexx_epi16() instruction. We really need a macro.
154// We use: v / 255 = (v * 0x8081) >> 23, where v = alpha * {r,g,b} is a 16bit
155// value.
156#define APPLY_ALPHA(RGBX, SHUFFLE) do { \
157 const __m128i argb0 = _mm_loadu_si128((const __m128i*)&(RGBX)); \
158 const __m128i argb1_lo = _mm_unpacklo_epi8(argb0, zero); \
159 const __m128i argb1_hi = _mm_unpackhi_epi8(argb0, zero); \
160 const __m128i alpha0_lo = _mm_or_si128(argb1_lo, kMask); \
161 const __m128i alpha0_hi = _mm_or_si128(argb1_hi, kMask); \
162 const __m128i alpha1_lo = _mm_shufflelo_epi16(alpha0_lo, SHUFFLE); \
163 const __m128i alpha1_hi = _mm_shufflelo_epi16(alpha0_hi, SHUFFLE); \
164 const __m128i alpha2_lo = _mm_shufflehi_epi16(alpha1_lo, SHUFFLE); \
165 const __m128i alpha2_hi = _mm_shufflehi_epi16(alpha1_hi, SHUFFLE); \
166 /* alpha2 = [ff a0 a0 a0][ff a1 a1 a1] */ \
167 const __m128i A0_lo = _mm_mullo_epi16(alpha2_lo, argb1_lo); \
168 const __m128i A0_hi = _mm_mullo_epi16(alpha2_hi, argb1_hi); \
169 const __m128i A1_lo = _mm_mulhi_epu16(A0_lo, kMult); \
170 const __m128i A1_hi = _mm_mulhi_epu16(A0_hi, kMult); \
171 const __m128i A2_lo = _mm_srli_epi16(A1_lo, 7); \
172 const __m128i A2_hi = _mm_srli_epi16(A1_hi, 7); \
173 const __m128i A3 = _mm_packus_epi16(A2_lo, A2_hi); \
174 _mm_storeu_si128((__m128i*)&(RGBX), A3); \
175} while (0)
176
177static void ApplyAlphaMultiply_SSE2(uint8_t* rgba, int alpha_first,
178 int w, int h, int stride) {
179 const __m128i zero = _mm_setzero_si128();
180 const __m128i kMult = _mm_set1_epi16(0x8081u);
181 const __m128i kMask = _mm_set_epi16(0, 0xff, 0xff, 0, 0, 0xff, 0xff, 0);
182 const int kSpan = 4;
183 while (h-- > 0) {
184 uint32_t* const rgbx = (uint32_t*)rgba;
185 int i;
186 if (!alpha_first) {
187 for (i = 0; i + kSpan <= w; i += kSpan) {
188 APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(2, 3, 3, 3));
189 }
190 } else {
191 for (i = 0; i + kSpan <= w; i += kSpan) {
192 APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(0, 0, 0, 1));
193 }
194 }
195 // Finish with left-overs.
196 for (; i < w; ++i) {
197 uint8_t* const rgb = rgba + (alpha_first ? 1 : 0);
198 const uint8_t* const alpha = rgba + (alpha_first ? 0 : 3);
199 const uint32_t a = alpha[4 * i];
200 if (a != 0xff) {
201 const uint32_t mult = MULTIPLIER(a);
202 rgb[4 * i + 0] = PREMULTIPLY(rgb[4 * i + 0], mult);
203 rgb[4 * i + 1] = PREMULTIPLY(rgb[4 * i + 1], mult);
204 rgb[4 * i + 2] = PREMULTIPLY(rgb[4 * i + 2], mult);
205 }
206 }
207 rgba += stride;
208 }
209}
210#undef MULTIPLIER
211#undef PREMULTIPLY
212
213//------------------------------------------------------------------------------
214// Alpha detection
215
216static int HasAlpha8b_SSE2(const uint8_t* src, int length) {
217 const __m128i all_0xff = _mm_set1_epi8((char)0xff);
218 int i = 0;
219 for (; i + 16 <= length; i += 16) {
220 const __m128i v = _mm_loadu_si128((const __m128i*)(src + i));
221 const __m128i bits = _mm_cmpeq_epi8(v, all_0xff);
222 const int mask = _mm_movemask_epi8(bits);
223 if (mask != 0xffff) return 1;
224 }
225 for (; i < length; ++i) if (src[i] != 0xff) return 1;
226 return 0;
227}
228
229static int HasAlpha32b_SSE2(const uint8_t* src, int length) {
230 const __m128i alpha_mask = _mm_set1_epi32(0xff);
231 const __m128i all_0xff = _mm_set1_epi8((char)0xff);
232 int i = 0;
233 // We don't know if we can access the last 3 bytes after the last alpha
234 // value 'src[4 * length - 4]' (because we don't know if alpha is the first
235 // or the last byte of the quadruplet). Hence the '-3' protection below.
236 length = length * 4 - 3; // size in bytes
237 for (; i + 64 <= length; i += 64) {
238 const __m128i a0 = _mm_loadu_si128((const __m128i*)(src + i + 0));
239 const __m128i a1 = _mm_loadu_si128((const __m128i*)(src + i + 16));
240 const __m128i a2 = _mm_loadu_si128((const __m128i*)(src + i + 32));
241 const __m128i a3 = _mm_loadu_si128((const __m128i*)(src + i + 48));
242 const __m128i b0 = _mm_and_si128(a0, alpha_mask);
243 const __m128i b1 = _mm_and_si128(a1, alpha_mask);
244 const __m128i b2 = _mm_and_si128(a2, alpha_mask);
245 const __m128i b3 = _mm_and_si128(a3, alpha_mask);
246 const __m128i c0 = _mm_packs_epi32(b0, b1);
247 const __m128i c1 = _mm_packs_epi32(b2, b3);
248 const __m128i d = _mm_packus_epi16(c0, c1);
249 const __m128i bits = _mm_cmpeq_epi8(d, all_0xff);
250 const int mask = _mm_movemask_epi8(bits);
251 if (mask != 0xffff) return 1;
252 }
253 for (; i + 32 <= length; i += 32) {
254 const __m128i a0 = _mm_loadu_si128((const __m128i*)(src + i + 0));
255 const __m128i a1 = _mm_loadu_si128((const __m128i*)(src + i + 16));
256 const __m128i b0 = _mm_and_si128(a0, alpha_mask);
257 const __m128i b1 = _mm_and_si128(a1, alpha_mask);
258 const __m128i c = _mm_packs_epi32(b0, b1);
259 const __m128i d = _mm_packus_epi16(c, c);
260 const __m128i bits = _mm_cmpeq_epi8(d, all_0xff);
261 const int mask = _mm_movemask_epi8(bits);
262 if (mask != 0xffff) return 1;
263 }
264 for (; i <= length; i += 4) if (src[i] != 0xff) return 1;
265 return 0;
266}
267
268// -----------------------------------------------------------------------------
269// Apply alpha value to rows
270
271static void MultARGBRow_SSE2(uint32_t* const ptr, int width, int inverse) {
272 int x = 0;
273 if (!inverse) {
274 const int kSpan = 2;
275 const __m128i zero = _mm_setzero_si128();
276 const __m128i k128 = _mm_set1_epi16(128);
277 const __m128i kMult = _mm_set1_epi16(0x0101);
278 const __m128i kMask = _mm_set_epi16(0, 0xff, 0, 0, 0, 0xff, 0, 0);
279 for (x = 0; x + kSpan <= width; x += kSpan) {
280 // To compute 'result = (int)(a * x / 255. + .5)', we use:
281 // tmp = a * v + 128, result = (tmp * 0x0101u) >> 16
282 const __m128i A0 = _mm_loadl_epi64((const __m128i*)&ptr[x]);
283 const __m128i A1 = _mm_unpacklo_epi8(A0, zero);
284 const __m128i A2 = _mm_or_si128(A1, kMask);
285 const __m128i A3 = _mm_shufflelo_epi16(A2, _MM_SHUFFLE(2, 3, 3, 3));
286 const __m128i A4 = _mm_shufflehi_epi16(A3, _MM_SHUFFLE(2, 3, 3, 3));
287 // here, A4 = [ff a0 a0 a0][ff a1 a1 a1]
288 const __m128i A5 = _mm_mullo_epi16(A4, A1);
289 const __m128i A6 = _mm_add_epi16(A5, k128);
290 const __m128i A7 = _mm_mulhi_epu16(A6, kMult);
291 const __m128i A10 = _mm_packus_epi16(A7, zero);
292 _mm_storel_epi64((__m128i*)&ptr[x], A10);
293 }
294 }
295 width -= x;
296 if (width > 0) WebPMultARGBRow_C(ptr + x, width, inverse);
297}
298
299static void MultRow_SSE2(uint8_t* const ptr, const uint8_t* const alpha,
300 int width, int inverse) {
301 int x = 0;
302 if (!inverse) {
303 const __m128i zero = _mm_setzero_si128();
304 const __m128i k128 = _mm_set1_epi16(128);
305 const __m128i kMult = _mm_set1_epi16(0x0101);
306 for (x = 0; x + 8 <= width; x += 8) {
307 const __m128i v0 = _mm_loadl_epi64((__m128i*)&ptr[x]);
308 const __m128i a0 = _mm_loadl_epi64((const __m128i*)&alpha[x]);
309 const __m128i v1 = _mm_unpacklo_epi8(v0, zero);
310 const __m128i a1 = _mm_unpacklo_epi8(a0, zero);
311 const __m128i v2 = _mm_mullo_epi16(v1, a1);
312 const __m128i v3 = _mm_add_epi16(v2, k128);
313 const __m128i v4 = _mm_mulhi_epu16(v3, kMult);
314 const __m128i v5 = _mm_packus_epi16(v4, zero);
315 _mm_storel_epi64((__m128i*)&ptr[x], v5);
316 }
317 }
318 width -= x;
319 if (width > 0) WebPMultRow_C(ptr + x, alpha + x, width, inverse);
320}
321
322//------------------------------------------------------------------------------
323// Entry point
324
325extern void WebPInitAlphaProcessingSSE2(void);
326
327WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingSSE2(void) {
328 WebPMultARGBRow = MultARGBRow_SSE2;
329 WebPMultRow = MultRow_SSE2;
330 WebPApplyAlphaMultiply = ApplyAlphaMultiply_SSE2;
331 WebPDispatchAlpha = DispatchAlpha_SSE2;
332 WebPDispatchAlphaToGreen = DispatchAlphaToGreen_SSE2;
333 WebPExtractAlpha = ExtractAlpha_SSE2;
334
335 WebPHasAlpha8b = HasAlpha8b_SSE2;
336 WebPHasAlpha32b = HasAlpha32b_SSE2;
337}
338
339#else // !WEBP_USE_SSE2
340
341WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingSSE2)
342
343#endif // WEBP_USE_SSE2
344