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 "./dsp.h"
15
16 #if defined(WEBP_USE_NEON)
17
18 #include <arm_neon.h>
19
20 #include "./lossless.h"
21 #include "./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(const uint8x16_t argb,const uint8x16_t shuffle)39 static WEBP_INLINE uint8x16_t DoGreenShuffle(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(const uint8x16_t argb,const uint8x8_t shuffle)48 static WEBP_INLINE uint8x16_t DoGreenShuffle(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(uint32_t * argb_data,int num_pixels)55 static void SubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixels) {
56 const uint32_t* const end = argb_data + (num_pixels & ~3);
57 #ifdef USE_VTBLQ
58 const uint8x16_t shuffle = vld1q_u8(kGreenShuffle);
59 #else
60 const uint8x8_t shuffle = vld1_u8(kGreenShuffle);
61 #endif
62 for (; argb_data < end; argb_data += 4) {
63 const uint8x16_t argb = vld1q_u8((uint8_t*)argb_data);
64 const uint8x16_t greens = DoGreenShuffle(argb, shuffle);
65 vst1q_u8((uint8_t*)argb_data, vsubq_u8(argb, greens));
66 }
67 // fallthrough and finish off with plain-C
68 VP8LSubtractGreenFromBlueAndRed_C(argb_data, num_pixels & 3);
69 }
70
71 //------------------------------------------------------------------------------
72 // Color Transform
73
TransformColor(const VP8LMultipliers * const m,uint32_t * argb_data,int num_pixels)74 static void TransformColor(const VP8LMultipliers* const m,
75 uint32_t* argb_data, int num_pixels) {
76 // sign-extended multiplying constants, pre-shifted by 6.
77 #define CST(X) (((int16_t)(m->X << 8)) >> 6)
78 const int16_t rb[8] = {
79 CST(green_to_blue_), CST(green_to_red_),
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 };
84 const int16x8_t mults_rb = vld1q_s16(rb);
85 const int16_t b2[8] = {
86 0, CST(red_to_blue_), 0, CST(red_to_blue_),
87 0, CST(red_to_blue_), 0, CST(red_to_blue_),
88 };
89 const int16x8_t mults_b2 = vld1q_s16(b2);
90 #undef CST
91 #ifdef USE_VTBLQ
92 static const uint8_t kg0g0[16] = {
93 255, 1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13
94 };
95 const uint8x16_t shuffle = vld1q_u8(kg0g0);
96 #else
97 static const uint8_t k0g0g[8] = { 255, 1, 255, 1, 255, 5, 255, 5 };
98 const uint8x8_t shuffle = vld1_u8(k0g0g);
99 #endif
100 const uint32x4_t mask_rb = vdupq_n_u32(0x00ff00ffu); // red-blue masks
101 int i;
102 for (i = 0; i + 4 <= num_pixels; i += 4) {
103 const uint8x16_t in = vld1q_u8((uint8_t*)(argb_data + i));
104 // 0 g 0 g
105 const uint8x16_t greens = DoGreenShuffle(in, shuffle);
106 // x dr x db1
107 const int16x8_t A = vqdmulhq_s16(vreinterpretq_s16_u8(greens), mults_rb);
108 // r 0 b 0
109 const int16x8_t B = vshlq_n_s16(vreinterpretq_s16_u8(in), 8);
110 // x db2 0 0
111 const int16x8_t C = vqdmulhq_s16(B, mults_b2);
112 // 0 0 x db2
113 const uint32x4_t D = vshrq_n_u32(vreinterpretq_u32_s16(C), 16);
114 // x dr x db
115 const int8x16_t E = vaddq_s8(vreinterpretq_s8_u32(D),
116 vreinterpretq_s8_s16(A));
117 // 0 dr 0 db
118 const uint32x4_t F = vandq_u32(vreinterpretq_u32_s8(E), mask_rb);
119 const int8x16_t out = vsubq_s8(vreinterpretq_s8_u8(in),
120 vreinterpretq_s8_u32(F));
121 vst1q_s8((int8_t*)(argb_data + i), out);
122 }
123 // fallthrough and finish off with plain-C
124 VP8LTransformColor_C(m, argb_data + i, num_pixels - i);
125 }
126
127 #undef USE_VTBLQ
128
129 //------------------------------------------------------------------------------
130 // Entry point
131
132 extern void VP8LEncDspInitNEON(void);
133
VP8LEncDspInitNEON(void)134 WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitNEON(void) {
135 VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed;
136 VP8LTransformColor = TransformColor;
137 }
138
139 #else // !WEBP_USE_NEON
140
141 WEBP_DSP_INIT_STUB(VP8LEncDspInitNEON)
142
143 #endif // WEBP_USE_NEON
144