1 // Copyright 2017 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, NEON version.
11 //
12 // Author: Skal ([email protected])
13
14 #include "src/dsp/dsp.h"
15
16 #if defined(WEBP_USE_NEON)
17
18 #include "src/dsp/neon.h"
19
20 //------------------------------------------------------------------------------
21
22 #define MULTIPLIER(a) ((a) * 0x8081)
23 #define PREMULTIPLY(x, m) (((x) * (m)) >> 23)
24
25 #define MULTIPLY_BY_ALPHA(V, ALPHA, OTHER) do { \
26 const uint8x8_t alpha = (V).val[(ALPHA)]; \
27 const uint16x8_t r1 = vmull_u8((V).val[1], alpha); \
28 const uint16x8_t g1 = vmull_u8((V).val[2], alpha); \
29 const uint16x8_t b1 = vmull_u8((V).val[(OTHER)], alpha); \
30 /* we use: v / 255 = (v + 1 + (v >> 8)) >> 8 */ \
31 const uint16x8_t r2 = vsraq_n_u16(r1, r1, 8); \
32 const uint16x8_t g2 = vsraq_n_u16(g1, g1, 8); \
33 const uint16x8_t b2 = vsraq_n_u16(b1, b1, 8); \
34 const uint16x8_t r3 = vaddq_u16(r2, kOne); \
35 const uint16x8_t g3 = vaddq_u16(g2, kOne); \
36 const uint16x8_t b3 = vaddq_u16(b2, kOne); \
37 (V).val[1] = vshrn_n_u16(r3, 8); \
38 (V).val[2] = vshrn_n_u16(g3, 8); \
39 (V).val[(OTHER)] = vshrn_n_u16(b3, 8); \
40 } while (0)
41
ApplyAlphaMultiply_NEON(uint8_t * rgba,int alpha_first,int w,int h,int stride)42 static void ApplyAlphaMultiply_NEON(uint8_t* rgba, int alpha_first,
43 int w, int h, int stride) {
44 const uint16x8_t kOne = vdupq_n_u16(1u);
45 while (h-- > 0) {
46 uint32_t* const rgbx = (uint32_t*)rgba;
47 int i = 0;
48 if (alpha_first) {
49 for (; i + 8 <= w; i += 8) {
50 // load aaaa...|rrrr...|gggg...|bbbb...
51 uint8x8x4_t RGBX = vld4_u8((const uint8_t*)(rgbx + i));
52 MULTIPLY_BY_ALPHA(RGBX, 0, 3);
53 vst4_u8((uint8_t*)(rgbx + i), RGBX);
54 }
55 } else {
56 for (; i + 8 <= w; i += 8) {
57 uint8x8x4_t RGBX = vld4_u8((const uint8_t*)(rgbx + i));
58 MULTIPLY_BY_ALPHA(RGBX, 3, 0);
59 vst4_u8((uint8_t*)(rgbx + i), RGBX);
60 }
61 }
62 // Finish with left-overs.
63 for (; i < w; ++i) {
64 uint8_t* const rgb = rgba + (alpha_first ? 1 : 0);
65 const uint8_t* const alpha = rgba + (alpha_first ? 0 : 3);
66 const uint32_t a = alpha[4 * i];
67 if (a != 0xff) {
68 const uint32_t mult = MULTIPLIER(a);
69 rgb[4 * i + 0] = PREMULTIPLY(rgb[4 * i + 0], mult);
70 rgb[4 * i + 1] = PREMULTIPLY(rgb[4 * i + 1], mult);
71 rgb[4 * i + 2] = PREMULTIPLY(rgb[4 * i + 2], mult);
72 }
73 }
74 rgba += stride;
75 }
76 }
77 #undef MULTIPLY_BY_ALPHA
78 #undef MULTIPLIER
79 #undef PREMULTIPLY
80
81 //------------------------------------------------------------------------------
82
DispatchAlpha_NEON(const uint8_t * WEBP_RESTRICT alpha,int alpha_stride,int width,int height,uint8_t * WEBP_RESTRICT dst,int dst_stride)83 static int DispatchAlpha_NEON(const uint8_t* WEBP_RESTRICT alpha,
84 int alpha_stride, int width, int height,
85 uint8_t* WEBP_RESTRICT dst, int dst_stride) {
86 uint32_t alpha_mask = 0xffu;
87 uint8x8_t mask8 = vdup_n_u8(0xff);
88 uint32_t tmp[2];
89 int i, j;
90 for (j = 0; j < height; ++j) {
91 // We don't know if alpha is first or last in dst[] (depending on rgbA/Argb
92 // mode). So we must be sure dst[4*i + 8 - 1] is writable for the store.
93 // Hence the test with 'width - 1' instead of just 'width'.
94 for (i = 0; i + 8 <= width - 1; i += 8) {
95 uint8x8x4_t rgbX = vld4_u8((const uint8_t*)(dst + 4 * i));
96 const uint8x8_t alphas = vld1_u8(alpha + i);
97 rgbX.val[0] = alphas;
98 vst4_u8((uint8_t*)(dst + 4 * i), rgbX);
99 mask8 = vand_u8(mask8, alphas);
100 }
101 for (; i < width; ++i) {
102 const uint32_t alpha_value = alpha[i];
103 dst[4 * i] = alpha_value;
104 alpha_mask &= alpha_value;
105 }
106 alpha += alpha_stride;
107 dst += dst_stride;
108 }
109 vst1_u8((uint8_t*)tmp, mask8);
110 alpha_mask *= 0x01010101;
111 alpha_mask &= tmp[0];
112 alpha_mask &= tmp[1];
113 return (alpha_mask != 0xffffffffu);
114 }
115
DispatchAlphaToGreen_NEON(const uint8_t * WEBP_RESTRICT alpha,int alpha_stride,int width,int height,uint32_t * WEBP_RESTRICT dst,int dst_stride)116 static void DispatchAlphaToGreen_NEON(const uint8_t* WEBP_RESTRICT alpha,
117 int alpha_stride, int width, int height,
118 uint32_t* WEBP_RESTRICT dst,
119 int dst_stride) {
120 int i, j;
121 uint8x8x4_t greens; // leave A/R/B channels zero'd.
122 greens.val[0] = vdup_n_u8(0);
123 greens.val[2] = vdup_n_u8(0);
124 greens.val[3] = vdup_n_u8(0);
125 for (j = 0; j < height; ++j) {
126 for (i = 0; i + 8 <= width; i += 8) {
127 greens.val[1] = vld1_u8(alpha + i);
128 vst4_u8((uint8_t*)(dst + i), greens);
129 }
130 for (; i < width; ++i) dst[i] = alpha[i] << 8;
131 alpha += alpha_stride;
132 dst += dst_stride;
133 }
134 }
135
ExtractAlpha_NEON(const uint8_t * WEBP_RESTRICT argb,int argb_stride,int width,int height,uint8_t * WEBP_RESTRICT alpha,int alpha_stride)136 static int ExtractAlpha_NEON(const uint8_t* WEBP_RESTRICT argb, int argb_stride,
137 int width, int height,
138 uint8_t* WEBP_RESTRICT alpha, int alpha_stride) {
139 uint32_t alpha_mask = 0xffu;
140 uint8x8_t mask8 = vdup_n_u8(0xff);
141 uint32_t tmp[2];
142 int i, j;
143 for (j = 0; j < height; ++j) {
144 // We don't know if alpha is first or last in dst[] (depending on rgbA/Argb
145 // mode). So we must be sure dst[4*i + 8 - 1] is writable for the store.
146 // Hence the test with 'width - 1' instead of just 'width'.
147 for (i = 0; i + 8 <= width - 1; i += 8) {
148 const uint8x8x4_t rgbX = vld4_u8((const uint8_t*)(argb + 4 * i));
149 const uint8x8_t alphas = rgbX.val[0];
150 vst1_u8((uint8_t*)(alpha + i), alphas);
151 mask8 = vand_u8(mask8, alphas);
152 }
153 for (; i < width; ++i) {
154 alpha[i] = argb[4 * i];
155 alpha_mask &= alpha[i];
156 }
157 argb += argb_stride;
158 alpha += alpha_stride;
159 }
160 vst1_u8((uint8_t*)tmp, mask8);
161 alpha_mask *= 0x01010101;
162 alpha_mask &= tmp[0];
163 alpha_mask &= tmp[1];
164 return (alpha_mask == 0xffffffffu);
165 }
166
ExtractGreen_NEON(const uint32_t * WEBP_RESTRICT argb,uint8_t * WEBP_RESTRICT alpha,int size)167 static void ExtractGreen_NEON(const uint32_t* WEBP_RESTRICT argb,
168 uint8_t* WEBP_RESTRICT alpha, int size) {
169 int i;
170 for (i = 0; i + 16 <= size; i += 16) {
171 const uint8x16x4_t rgbX = vld4q_u8((const uint8_t*)(argb + i));
172 const uint8x16_t greens = rgbX.val[1];
173 vst1q_u8(alpha + i, greens);
174 }
175 for (; i < size; ++i) alpha[i] = (argb[i] >> 8) & 0xff;
176 }
177
178 //------------------------------------------------------------------------------
179
180 extern void WebPInitAlphaProcessingNEON(void);
181
WebPInitAlphaProcessingNEON(void)182 WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingNEON(void) {
183 WebPApplyAlphaMultiply = ApplyAlphaMultiply_NEON;
184 WebPDispatchAlpha = DispatchAlpha_NEON;
185 WebPDispatchAlphaToGreen = DispatchAlphaToGreen_NEON;
186 WebPExtractAlpha = ExtractAlpha_NEON;
187 WebPExtractGreen = ExtractGreen_NEON;
188 }
189
190 #else // !WEBP_USE_NEON
191
192 WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingNEON)
193
194 #endif // WEBP_USE_NEON
195