1// Copyright 2015 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// NEON variant of methods for lossless encoder
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#include "src/dsp/dsp.h"
15
16#if defined(WEBP_USE_NEON)
17
18#include <arm_neon.h>
19
20#include "src/dsp/lossless.h"
21#include "src/dsp/neon.h"
22
23//------------------------------------------------------------------------------
24// Subtract-Green Transform
25
26// vtbl?_u8 are marked unavailable for iOS arm64 with Xcode < 6.3, use
27// non-standard versions there.
28#if defined(__APPLE__) && WEBP_AARCH64 && \
29 defined(__apple_build_version__) && (__apple_build_version__< 6020037)
30#define USE_VTBLQ
31#endif
32
33#ifdef USE_VTBLQ
34// 255 = byte will be zeroed
35static const uint8_t kGreenShuffle[16] = {
36 1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13, 255
37};
38
39static WEBP_INLINE uint8x16_t DoGreenShuffle_NEON(const uint8x16_t argb,
40 const uint8x16_t shuffle) {
41 return vcombine_u8(vtbl1q_u8(argb, vget_low_u8(shuffle)),
42 vtbl1q_u8(argb, vget_high_u8(shuffle)));
43}
44#else // !USE_VTBLQ
45// 255 = byte will be zeroed
46static const uint8_t kGreenShuffle[8] = { 1, 255, 1, 255, 5, 255, 5, 255 };
47
48static WEBP_INLINE uint8x16_t DoGreenShuffle_NEON(const uint8x16_t argb,
49 const uint8x8_t shuffle) {
50 return vcombine_u8(vtbl1_u8(vget_low_u8(argb), shuffle),
51 vtbl1_u8(vget_high_u8(argb), shuffle));
52}
53#endif // USE_VTBLQ
54
55static void SubtractGreenFromBlueAndRed_NEON(uint32_t* argb_data,
56 int num_pixels) {
57 const uint32_t* const end = argb_data + (num_pixels & ~3);
58#ifdef USE_VTBLQ
59 const uint8x16_t shuffle = vld1q_u8(kGreenShuffle);
60#else
61 const uint8x8_t shuffle = vld1_u8(kGreenShuffle);
62#endif
63 for (; argb_data < end; argb_data += 4) {
64 const uint8x16_t argb = vld1q_u8((uint8_t*)argb_data);
65 const uint8x16_t greens = DoGreenShuffle_NEON(argb, shuffle);
66 vst1q_u8((uint8_t*)argb_data, vsubq_u8(argb, greens));
67 }
68 // fallthrough and finish off with plain-C
69 VP8LSubtractGreenFromBlueAndRed_C(argb_data, num_pixels & 3);
70}
71
72//------------------------------------------------------------------------------
73// Color Transform
74
75static void TransformColor_NEON(const VP8LMultipliers* const m,
76 uint32_t* argb_data, int num_pixels) {
77 // sign-extended multiplying constants, pre-shifted by 6.
78#define CST(X) (((int16_t)(m->X << 8)) >> 6)
79 const int16_t rb[8] = {
80 CST(green_to_blue_), CST(green_to_red_),
81 CST(green_to_blue_), CST(green_to_red_),
82 CST(green_to_blue_), CST(green_to_red_),
83 CST(green_to_blue_), CST(green_to_red_)
84 };
85 const int16x8_t mults_rb = vld1q_s16(rb);
86 const int16_t b2[8] = {
87 0, CST(red_to_blue_), 0, CST(red_to_blue_),
88 0, CST(red_to_blue_), 0, CST(red_to_blue_),
89 };
90 const int16x8_t mults_b2 = vld1q_s16(b2);
91#undef CST
92#ifdef USE_VTBLQ
93 static const uint8_t kg0g0[16] = {
94 255, 1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13
95 };
96 const uint8x16_t shuffle = vld1q_u8(kg0g0);
97#else
98 static const uint8_t k0g0g[8] = { 255, 1, 255, 1, 255, 5, 255, 5 };
99 const uint8x8_t shuffle = vld1_u8(k0g0g);
100#endif
101 const uint32x4_t mask_rb = vdupq_n_u32(0x00ff00ffu); // red-blue masks
102 int i;
103 for (i = 0; i + 4 <= num_pixels; i += 4) {
104 const uint8x16_t in = vld1q_u8((uint8_t*)(argb_data + i));
105 // 0 g 0 g
106 const uint8x16_t greens = DoGreenShuffle_NEON(in, shuffle);
107 // x dr x db1
108 const int16x8_t A = vqdmulhq_s16(vreinterpretq_s16_u8(greens), mults_rb);
109 // r 0 b 0
110 const int16x8_t B = vshlq_n_s16(vreinterpretq_s16_u8(in), 8);
111 // x db2 0 0
112 const int16x8_t C = vqdmulhq_s16(B, mults_b2);
113 // 0 0 x db2
114 const uint32x4_t D = vshrq_n_u32(vreinterpretq_u32_s16(C), 16);
115 // x dr x db
116 const int8x16_t E = vaddq_s8(vreinterpretq_s8_u32(D),
117 vreinterpretq_s8_s16(A));
118 // 0 dr 0 db
119 const uint32x4_t F = vandq_u32(vreinterpretq_u32_s8(E), mask_rb);
120 const int8x16_t out = vsubq_s8(vreinterpretq_s8_u8(in),
121 vreinterpretq_s8_u32(F));
122 vst1q_s8((int8_t*)(argb_data + i), out);
123 }
124 // fallthrough and finish off with plain-C
125 VP8LTransformColor_C(m, argb_data + i, num_pixels - i);
126}
127
128#undef USE_VTBLQ
129
130//------------------------------------------------------------------------------
131// Entry point
132
133extern void VP8LEncDspInitNEON(void);
134
135WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitNEON(void) {
136 VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed_NEON;
137 VP8LTransformColor = TransformColor_NEON;
138}
139
140#else // !WEBP_USE_NEON
141
142WEBP_DSP_INIT_STUB(VP8LEncDspInitNEON)
143
144#endif // WEBP_USE_NEON
145