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 (at) 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 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 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 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 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); 133 134 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
