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 (pascal.massimino@gmail.com)
13
14#include "./dsp.h"
15
16#if defined(WEBP_USE_NEON)
17
18#include "./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
42static 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
83static int DispatchAlpha_NEON(const uint8_t* alpha, int alpha_stride,
84 int width, int height,
85 uint8_t* dst, int dst_stride) {
86 uint32_t alpha_mask = 0xffffffffu;
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 &= tmp[0];
111 alpha_mask &= tmp[1];
112 return (alpha_mask != 0xffffffffu);
113}
114
115static void DispatchAlphaToGreen_NEON(const uint8_t* alpha, int alpha_stride,
116 int width, int height,
117 uint32_t* dst, int dst_stride) {
118 int i, j;
119 uint8x8x4_t greens; // leave A/R/B channels zero'd.
120 greens.val[0] = vdup_n_u8(0);
121 greens.val[2] = vdup_n_u8(0);
122 greens.val[3] = vdup_n_u8(0);
123 for (j = 0; j < height; ++j) {
124 for (i = 0; i + 8 <= width; i += 8) {
125 greens.val[1] = vld1_u8(alpha + i);
126 vst4_u8((uint8_t*)(dst + i), greens);
127 }
128 for (; i < width; ++i) dst[i] = alpha[i] << 8;
129 alpha += alpha_stride;
130 dst += dst_stride;
131 }
132}
133
134static int ExtractAlpha_NEON(const uint8_t* argb, int argb_stride,
135 int width, int height,
136 uint8_t* alpha, int alpha_stride) {
137 uint32_t alpha_mask = 0xffffffffu;
138 uint8x8_t mask8 = vdup_n_u8(0xff);
139 uint32_t tmp[2];
140 int i, j;
141 for (j = 0; j < height; ++j) {
142 // We don't know if alpha is first or last in dst[] (depending on rgbA/Argb
143 // mode). So we must be sure dst[4*i + 8 - 1] is writable for the store.
144 // Hence the test with 'width - 1' instead of just 'width'.
145 for (i = 0; i + 8 <= width - 1; i += 8) {
146 const uint8x8x4_t rgbX = vld4_u8((const uint8_t*)(argb + 4 * i));
147 const uint8x8_t alphas = rgbX.val[0];
148 vst1_u8((uint8_t*)(alpha + i), alphas);
149 mask8 = vand_u8(mask8, alphas);
150 }
151 for (; i < width; ++i) {
152 alpha[i] = argb[4 * i];
153 alpha_mask &= alpha[i];
154 }
155 argb += argb_stride;
156 alpha += alpha_stride;
157 }
158 vst1_u8((uint8_t*)tmp, mask8);
159 alpha_mask &= tmp[0];
160 alpha_mask &= tmp[1];
161 return (alpha_mask == 0xffffffffu);
162}
163
164static void ExtractGreen_NEON(const uint32_t* argb,
165 uint8_t* alpha, int size) {
166 int i;
167 for (i = 0; i + 16 <= size; i += 16) {
168 const uint8x16x4_t rgbX = vld4q_u8((const uint8_t*)(argb + i));
169 const uint8x16_t greens = rgbX.val[1];
170 vst1q_u8(alpha + i, greens);
171 }
172 for (; i < size; ++i) alpha[i] = (argb[i] >> 8) & 0xff;
173}
174
175//------------------------------------------------------------------------------
176
177extern void WebPInitAlphaProcessingNEON(void);
178
179WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingNEON(void) {
180 WebPApplyAlphaMultiply = ApplyAlphaMultiply_NEON;
181 WebPDispatchAlpha = DispatchAlpha_NEON;
182 WebPDispatchAlphaToGreen = DispatchAlphaToGreen_NEON;
183 WebPExtractAlpha = ExtractAlpha_NEON;
184 WebPExtractGreen = ExtractGreen_NEON;
185}
186
187#else // !WEBP_USE_NEON
188
189WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingNEON)
190
191#endif // WEBP_USE_NEON
192