1 /* 2 * Copyright 2014 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #include "SkTextureCompressor.h" 9 #include "SkTextureCompression_opts.h" 10 11 #include <arm_neon.h> 12 13 // Converts indices in each of the four bits of the register from 14 // 0, 1, 2, 3, 4, 5, 6, 7 15 // to 16 // 3, 2, 1, 0, 4, 5, 6, 7 17 // 18 // A more detailed explanation can be found in SkTextureCompressor::convert_indices 19 static inline uint8x16_t convert_indices(const uint8x16_t &x) { 20 static const int8x16_t kThree = { 21 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 22 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 23 }; 24 25 static const int8x16_t kZero = { 26 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 27 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 28 }; 29 30 // Take top three bits 31 int8x16_t sx = vreinterpretq_s8_u8(x); 32 33 // Negate ... 34 sx = vnegq_s8(sx); 35 36 // Add three... 37 sx = vaddq_s8(sx, kThree); 38 39 // Generate negatives mask 40 const int8x16_t mask = vreinterpretq_s8_u8(vcltq_s8(sx, kZero)); 41 42 // Absolute value 43 sx = vabsq_s8(sx); 44 45 // Add three to the values that were negative... 46 return vreinterpretq_u8_s8(vaddq_s8(sx, vandq_s8(mask, kThree))); 47 } 48 49 template<unsigned shift> 50 static inline uint64x2_t shift_swap(const uint64x2_t &x, const uint64x2_t &mask) { 51 uint64x2_t t = vandq_u64(mask, veorq_u64(x, vshrq_n_u64(x, shift))); 52 return veorq_u64(x, veorq_u64(t, vshlq_n_u64(t, shift))); 53 } 54 55 static inline uint64x2_t pack_indices(const uint64x2_t &x) { 56 // x: 00 a e 00 b f 00 c g 00 d h 00 i m 00 j n 00 k o 00 l p 57 58 static const uint64x2_t kMask1 = { 0x3FC0003FC00000ULL, 0x3FC0003FC00000ULL }; 59 uint64x2_t ret = shift_swap<10>(x, kMask1); 60 61 // x: b f 00 00 00 a e c g i m 00 00 00 d h j n 00 k o 00 l p 62 static const uint64x2_t kMask2 = { (0x3FULL << 52), (0x3FULL << 52) }; 63 static const uint64x2_t kMask3 = { (0x3FULL << 28), (0x3FULL << 28) }; 64 const uint64x2_t x1 = vandq_u64(vshlq_n_u64(ret, 52), kMask2); 65 const uint64x2_t x2 = vandq_u64(vshlq_n_u64(ret, 20), kMask3); 66 ret = vshrq_n_u64(vorrq_u64(ret, vorrq_u64(x1, x2)), 16); 67 68 // x: 00 00 00 00 00 00 00 00 b f l p a e c g i m k o d h j n 69 70 static const uint64x2_t kMask4 = { 0xFC0000ULL, 0xFC0000ULL }; 71 ret = shift_swap<6>(ret, kMask4); 72 73 #if defined (SK_CPU_BENDIAN) 74 // x: 00 00 00 00 00 00 00 00 b f l p a e i m c g k o d h j n 75 76 static const uint64x2_t kMask5 = { 0x3FULL, 0x3FULL }; 77 ret = shift_swap<36>(ret, kMask5); 78 79 // x: 00 00 00 00 00 00 00 00 b f j n a e i m c g k o d h l p 80 81 static const uint64x2_t kMask6 = { 0xFFF000000ULL, 0xFFF000000ULL }; 82 ret = shift_swap<12>(ret, kMask6); 83 #else 84 // x: 00 00 00 00 00 00 00 00 c g i m d h l p b f j n a e k o 85 86 static const uint64x2_t kMask5 = { 0xFC0ULL, 0xFC0ULL }; 87 ret = shift_swap<36>(ret, kMask5); 88 89 // x: 00 00 00 00 00 00 00 00 a e i m d h l p b f j n c g k o 90 91 static const uint64x2_t kMask6 = { (0xFFFULL << 36), (0xFFFULL << 36) }; 92 static const uint64x2_t kMask7 = { 0xFFFFFFULL, 0xFFFFFFULL }; 93 static const uint64x2_t kMask8 = { 0xFFFULL, 0xFFFULL }; 94 const uint64x2_t y1 = vandq_u64(ret, kMask6); 95 const uint64x2_t y2 = vshlq_n_u64(vandq_u64(ret, kMask7), 12); 96 const uint64x2_t y3 = vandq_u64(vshrq_n_u64(ret, 24), kMask8); 97 ret = vorrq_u64(y1, vorrq_u64(y2, y3)); 98 #endif 99 100 // x: 00 00 00 00 00 00 00 00 a e i m b f j n c g k o d h l p 101 102 // Set the header 103 static const uint64x2_t kHeader = { 0x8490000000000000ULL, 0x8490000000000000ULL }; 104 return vorrq_u64(kHeader, ret); 105 } 106 107 // Takes a row of alpha values and places the most significant three bits of each byte into 108 // the least significant bits of the same byte 109 static inline uint8x16_t make_index_row(const uint8x16_t &x) { 110 static const uint8x16_t kTopThreeMask = { 111 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 112 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 113 }; 114 return vshrq_n_u8(vandq_u8(x, kTopThreeMask), 5); 115 } 116 117 // Returns true if all of the bits in x are 0. 118 static inline bool is_zero(uint8x16_t x) { 119 // First experiments say that this is way slower than just examining the lanes 120 // but it might need a little more investigation. 121 #if 0 122 // This code path tests the system register for overflow. We trigger 123 // overflow by adding x to a register with all of its bits set. The 124 // first instruction sets the bits. 125 int reg; 126 asm ("VTST.8 %%q0, %q1, %q1\n" 127 "VQADD.u8 %q1, %%q0\n" 128 "VMRS %0, FPSCR\n" 129 : "=r"(reg) : "w"(vreinterpretq_f32_u8(x)) : "q0", "q1"); 130 131 // Bit 21 corresponds to the overflow flag. 132 return reg & (0x1 << 21); 133 #else 134 const uint64x2_t cvt = vreinterpretq_u64_u8(x); 135 const uint64_t l1 = vgetq_lane_u64(cvt, 0); 136 return (l1 == 0) && (l1 == vgetq_lane_u64(cvt, 1)); 137 #endif 138 } 139 140 #if defined (SK_CPU_BENDIAN) 141 static inline uint64x2_t fix_endianness(uint64x2_t x) { 142 return x; 143 } 144 #else 145 static inline uint64x2_t fix_endianness(uint64x2_t x) { 146 return vreinterpretq_u64_u8(vrev64q_u8(vreinterpretq_u8_u64(x))); 147 } 148 #endif 149 150 static void compress_r11eac_blocks(uint64_t* dst, const uint8_t* src, size_t rowBytes) { 151 152 // Try to avoid switching between vector and non-vector ops... 153 const uint8_t *const src1 = src; 154 const uint8_t *const src2 = src + rowBytes; 155 const uint8_t *const src3 = src + 2*rowBytes; 156 const uint8_t *const src4 = src + 3*rowBytes; 157 uint64_t *const dst1 = dst; 158 uint64_t *const dst2 = dst + 2; 159 160 const uint8x16_t alphaRow1 = vld1q_u8(src1); 161 const uint8x16_t alphaRow2 = vld1q_u8(src2); 162 const uint8x16_t alphaRow3 = vld1q_u8(src3); 163 const uint8x16_t alphaRow4 = vld1q_u8(src4); 164 165 const uint8x16_t cmp12 = vceqq_u8(alphaRow1, alphaRow2); 166 const uint8x16_t cmp34 = vceqq_u8(alphaRow3, alphaRow4); 167 const uint8x16_t cmp13 = vceqq_u8(alphaRow1, alphaRow3); 168 169 const uint8x16_t cmp = vandq_u8(vandq_u8(cmp12, cmp34), cmp13); 170 const uint8x16_t ncmp = vmvnq_u8(cmp); 171 const uint8x16_t nAlphaRow1 = vmvnq_u8(alphaRow1); 172 if (is_zero(ncmp)) { 173 if (is_zero(alphaRow1)) { 174 static const uint64x2_t kTransparent = { 0x0020000000002000ULL, 175 0x0020000000002000ULL }; 176 vst1q_u64(dst1, kTransparent); 177 vst1q_u64(dst2, kTransparent); 178 return; 179 } else if (is_zero(nAlphaRow1)) { 180 vst1q_u64(dst1, vreinterpretq_u64_u8(cmp)); 181 vst1q_u64(dst2, vreinterpretq_u64_u8(cmp)); 182 return; 183 } 184 } 185 186 const uint8x16_t indexRow1 = convert_indices(make_index_row(alphaRow1)); 187 const uint8x16_t indexRow2 = convert_indices(make_index_row(alphaRow2)); 188 const uint8x16_t indexRow3 = convert_indices(make_index_row(alphaRow3)); 189 const uint8x16_t indexRow4 = convert_indices(make_index_row(alphaRow4)); 190 191 const uint64x2_t indexRow12 = vreinterpretq_u64_u8( 192 vorrq_u8(vshlq_n_u8(indexRow1, 3), indexRow2)); 193 const uint64x2_t indexRow34 = vreinterpretq_u64_u8( 194 vorrq_u8(vshlq_n_u8(indexRow3, 3), indexRow4)); 195 196 const uint32x4x2_t blockIndices = vtrnq_u32(vreinterpretq_u32_u64(indexRow12), 197 vreinterpretq_u32_u64(indexRow34)); 198 const uint64x2_t blockIndicesLeft = vreinterpretq_u64_u32(vrev64q_u32(blockIndices.val[0])); 199 const uint64x2_t blockIndicesRight = vreinterpretq_u64_u32(vrev64q_u32(blockIndices.val[1])); 200 201 const uint64x2_t indicesLeft = fix_endianness(pack_indices(blockIndicesLeft)); 202 const uint64x2_t indicesRight = fix_endianness(pack_indices(blockIndicesRight)); 203 204 const uint64x2_t d1 = vcombine_u64(vget_low_u64(indicesLeft), vget_low_u64(indicesRight)); 205 const uint64x2_t d2 = vcombine_u64(vget_high_u64(indicesLeft), vget_high_u64(indicesRight)); 206 vst1q_u64(dst1, d1); 207 vst1q_u64(dst2, d2); 208 } 209 210 bool CompressA8toR11EAC_NEON(uint8_t* dst, const uint8_t* src, 211 int width, int height, size_t rowBytes) { 212 213 // Since we're going to operate on 4 blocks at a time, the src width 214 // must be a multiple of 16. However, the height only needs to be a 215 // multiple of 4 216 if (0 == width || 0 == height || (width % 16) != 0 || (height % 4) != 0) { 217 return SkTextureCompressor::CompressBufferToFormat( 218 dst, src, 219 kAlpha_8_SkColorType, 220 width, height, rowBytes, 221 SkTextureCompressor::kR11_EAC_Format, false); 222 } 223 224 const int blocksX = width >> 2; 225 const int blocksY = height >> 2; 226 227 SkASSERT((blocksX % 4) == 0); 228 229 uint64_t* encPtr = reinterpret_cast<uint64_t*>(dst); 230 for (int y = 0; y < blocksY; ++y) { 231 for (int x = 0; x < blocksX; x+=4) { 232 // Compress it 233 compress_r11eac_blocks(encPtr, src + 4*x, rowBytes); 234 encPtr += 4; 235 } 236 src += 4 * rowBytes; 237 } 238 return true; 239 } 240
