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__) && defined(__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
35 static const uint8_t kGreenShuffle[16] = {
36 1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13, 255
37 };
38
DoGreenShuffle_NEON(const uint8x16_t argb,const uint8x16_t shuffle)39 static 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
46 static const uint8_t kGreenShuffle[8] = { 1, 255, 1, 255, 5, 255, 5, 255 };
47
DoGreenShuffle_NEON(const uint8x16_t argb,const uint8x8_t shuffle)48 static 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
SubtractGreenFromBlueAndRed_NEON(uint32_t * argb_data,int num_pixels)55 static 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
TransformColor_NEON(const VP8LMultipliers * const m,uint32_t * argb_data,int num_pixels)75 static 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
133 extern void VP8LEncDspInitNEON(void);
134
VP8LEncDspInitNEON(void)135 WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitNEON(void) {
136 VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed_NEON;
137 VP8LTransformColor = TransformColor_NEON;
138 }
139
140 #else // !WEBP_USE_NEON
141
142 WEBP_DSP_INIT_STUB(VP8LEncDspInitNEON)
143
144 #endif // WEBP_USE_NEON
145