src/opts/SkTextureCompressor_opts.h - platform/external/skia - Gitiles

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #ifndef SkTextureCompressor_opts_DEFINED
 #define SkTextureCompressor_opts_DEFINED

 #include "SkOpts.h"

 namespace SK_OPTS_NS {

 #if defined(SK_ARM_HAS_NEON)
     // Converts indices in each of the four bits of the register from
     // 0, 1, 2, 3, 4, 5, 6, 7
     // to
     // 3, 2, 1, 0, 4, 5, 6, 7
     //
     // A more detailed explanation can be found in SkTextureCompressor::convert_indices
     static inline uint8x16_t convert_indices(const uint8x16_t &x) {
         static const int8x16_t kThree = {
             0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
             0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
         };

         static const int8x16_t kZero = {
             0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
             0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
         };

         // Take top three bits
         int8x16_t sx = vreinterpretq_s8_u8(x);

         // Negate ...
         sx = vnegq_s8(sx);

         // Add three...
         sx = vaddq_s8(sx, kThree);

         // Generate negatives mask
         const int8x16_t mask = vreinterpretq_s8_u8(vcltq_s8(sx, kZero));

         // Absolute value
         sx = vabsq_s8(sx);

         // Add three to the values that were negative...
         return vreinterpretq_u8_s8(vaddq_s8(sx, vandq_s8(mask, kThree)));
     }

     template<unsigned shift>
     static inline uint64x2_t shift_swap(const uint64x2_t &x, const uint64x2_t &mask) {
         uint64x2_t t = vandq_u64(mask, veorq_u64(x, vshrq_n_u64(x, shift)));
         return veorq_u64(x, veorq_u64(t, vshlq_n_u64(t, shift)));
     }

     static inline uint64x2_t pack_indices(const uint64x2_t &x) {
         // 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

         static const uint64x2_t kMask1 = { 0x3FC0003FC00000ULL, 0x3FC0003FC00000ULL };
         uint64x2_t ret = shift_swap<10>(x, kMask1);

         // 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
         static const uint64x2_t kMask2 = { (0x3FULL << 52), (0x3FULL << 52) };
         static const uint64x2_t kMask3 = { (0x3FULL << 28), (0x3FULL << 28) };
         const uint64x2_t x1 = vandq_u64(vshlq_n_u64(ret, 52), kMask2);
         const uint64x2_t x2 = vandq_u64(vshlq_n_u64(ret, 20), kMask3);
         ret = vshrq_n_u64(vorrq_u64(ret, vorrq_u64(x1, x2)), 16);

         // 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

         static const uint64x2_t kMask4 = { 0xFC0000ULL, 0xFC0000ULL };
         ret = shift_swap<6>(ret, kMask4);

     #if defined (SK_CPU_BENDIAN)
         // 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

         static const uint64x2_t kMask5 = { 0x3FULL, 0x3FULL };
         ret = shift_swap<36>(ret, kMask5);

         // 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

         static const uint64x2_t kMask6 = { 0xFFF000000ULL, 0xFFF000000ULL };
         ret = shift_swap<12>(ret, kMask6);
     #else
         // 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

         static const uint64x2_t kMask5 = { 0xFC0ULL, 0xFC0ULL };
         ret = shift_swap<36>(ret, kMask5);

         // 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

         static const uint64x2_t kMask6 = { (0xFFFULL << 36), (0xFFFULL << 36) };
         static const uint64x2_t kMask7 = { 0xFFFFFFULL, 0xFFFFFFULL };
         static const uint64x2_t kMask8 = { 0xFFFULL, 0xFFFULL };
         const uint64x2_t y1 = vandq_u64(ret, kMask6);
         const uint64x2_t y2 = vshlq_n_u64(vandq_u64(ret, kMask7), 12);
         const uint64x2_t y3 = vandq_u64(vshrq_n_u64(ret, 24), kMask8);
         ret = vorrq_u64(y1, vorrq_u64(y2, y3));
     #endif

         // 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

         // Set the header
         static const uint64x2_t kHeader = { 0x8490000000000000ULL, 0x8490000000000000ULL };
         return vorrq_u64(kHeader, ret);
     }

     // Takes a row of alpha values and places the most significant three bits of each byte into
     // the least significant bits of the same byte
     static inline uint8x16_t make_index_row(const uint8x16_t &x) {
         static const uint8x16_t kTopThreeMask = {
             0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0,
             0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0,
         };
         return vshrq_n_u8(vandq_u8(x, kTopThreeMask), 5);
     }

     // Returns true if all of the bits in x are 0.
     static inline bool is_zero(uint8x16_t x) {
     // First experiments say that this is way slower than just examining the lanes
     // but it might need a little more investigation.
     #if 0
         // This code path tests the system register for overflow. We trigger
         // overflow by adding x to a register with all of its bits set. The
         // first instruction sets the bits.
         int reg;
         asm ("VTST.8   %%q0, %q1, %q1\n"
              "VQADD.u8 %q1, %%q0\n"
              "VMRS     %0, FPSCR\n"
              : "=r"(reg) : "w"(vreinterpretq_f32_u8(x)) : "q0", "q1");

         // Bit 21 corresponds to the overflow flag.
         return reg & (0x1 << 21);
     #else
         const uint64x2_t cvt = vreinterpretq_u64_u8(x);
         const uint64_t l1 = vgetq_lane_u64(cvt, 0);
         return (l1 == 0) && (l1 == vgetq_lane_u64(cvt, 1));
     #endif
     }

     #if defined (SK_CPU_BENDIAN)
     static inline uint64x2_t fix_endianness(uint64x2_t x) {
         return x;
     }
     #else
     static inline uint64x2_t fix_endianness(uint64x2_t x) {
         return vreinterpretq_u64_u8(vrev64q_u8(vreinterpretq_u8_u64(x)));
     }
     #endif

     static void compress_r11eac_blocks(uint8_t* dst, const uint8_t* src, size_t rowBytes) {
         // Try to avoid switching between vector and non-vector ops...
         const uint8_t *const src1 = src;
         const uint8_t *const src2 = src + rowBytes;
         const uint8_t *const src3 = src + 2*rowBytes;
         const uint8_t *const src4 = src + 3*rowBytes;
         uint8_t *const dst1 = dst;
         uint8_t *const dst2 = dst + 16;

         const uint8x16_t alphaRow1 = vld1q_u8(src1);
         const uint8x16_t alphaRow2 = vld1q_u8(src2);
         const uint8x16_t alphaRow3 = vld1q_u8(src3);
         const uint8x16_t alphaRow4 = vld1q_u8(src4);

         const uint8x16_t cmp12 = vceqq_u8(alphaRow1, alphaRow2);
         const uint8x16_t cmp34 = vceqq_u8(alphaRow3, alphaRow4);
         const uint8x16_t cmp13 = vceqq_u8(alphaRow1, alphaRow3);

         const uint8x16_t cmp = vandq_u8(vandq_u8(cmp12, cmp34), cmp13);
         const uint8x16_t ncmp = vmvnq_u8(cmp);
         const uint8x16_t nAlphaRow1 = vmvnq_u8(alphaRow1);
         if (is_zero(ncmp)) {
             if (is_zero(alphaRow1)) {
                 static const uint64x2_t kTransparent = { 0x0020000000002000ULL,
                                                          0x0020000000002000ULL };
                 vst1q_u8(dst1, vreinterpretq_u8_u64(kTransparent));
                 vst1q_u8(dst2, vreinterpretq_u8_u64(kTransparent));
                 return;
             } else if (is_zero(nAlphaRow1)) {
                 vst1q_u8(dst1, cmp);
                 vst1q_u8(dst2, cmp);
                 return;
             }
         }

         const uint8x16_t indexRow1 = convert_indices(make_index_row(alphaRow1));
         const uint8x16_t indexRow2 = convert_indices(make_index_row(alphaRow2));
         const uint8x16_t indexRow3 = convert_indices(make_index_row(alphaRow3));
         const uint8x16_t indexRow4 = convert_indices(make_index_row(alphaRow4));

         const uint64x2_t indexRow12 = vreinterpretq_u64_u8(
             vorrq_u8(vshlq_n_u8(indexRow1, 3), indexRow2));
         const uint64x2_t indexRow34 = vreinterpretq_u64_u8(
             vorrq_u8(vshlq_n_u8(indexRow3, 3), indexRow4));

         const uint32x4x2_t blockIndices = vtrnq_u32(vreinterpretq_u32_u64(indexRow12),
                                                     vreinterpretq_u32_u64(indexRow34));
         const uint64x2_t blockIndicesLeft = vreinterpretq_u64_u32(vrev64q_u32(blockIndices.val[0]));
         const uint64x2_t blockIndicesRight = vreinterpretq_u64_u32(vrev64q_u32(blockIndices.val[1]));

         const uint64x2_t indicesLeft = fix_endianness(pack_indices(blockIndicesLeft));
         const uint64x2_t indicesRight = fix_endianness(pack_indices(blockIndicesRight));

         const uint64x2_t d1 = vcombine_u64(vget_low_u64(indicesLeft), vget_low_u64(indicesRight));
         const uint64x2_t d2 = vcombine_u64(vget_high_u64(indicesLeft), vget_high_u64(indicesRight));
         vst1q_u8(dst1, vreinterpretq_u8_u64(d1));
         vst1q_u8(dst2, vreinterpretq_u8_u64(d2));
     }

     static bool compress_a8_r11eac(uint8_t* dst, const uint8_t* src,
                                    int width, int height, size_t rowBytes) {

         // Since we're going to operate on 4 blocks at a time, the src width
         // must be a multiple of 16. However, the height only needs to be a
         // multiple of 4
         if (0 == width || 0 == height || (width % 16) != 0 || (height % 4) != 0) {
             return false;
         }

         const int blocksX = width >> 2;
         const int blocksY = height >> 2;

         SkASSERT((blocksX % 4) == 0);

         for (int y = 0; y < blocksY; ++y) {
             for (int x = 0; x < blocksX; x+=4) {
                 // Compress it
                 compress_r11eac_blocks(dst, src + 4*x, rowBytes);
                 dst += 32;
             }
             src += 4 * rowBytes;
         }
         return true;
     }

     static SkOpts::TextureCompressor texture_compressor(SkColorType ct,
                                                         SkTextureCompressor::Format fmt) {
         if (ct == kAlpha_8_SkColorType && fmt == SkTextureCompressor::kR11_EAC_Format) {
             return compress_a8_r11eac;
         }
         return nullptr;
     }
     static bool fill_block_dimensions(SkTextureCompressor::Format fmt, int* x, int* y) {
         if (fmt == SkTextureCompressor::kR11_EAC_Format) {
             *x = 16;
             *y = 4;
             return true;
         }
         return false;
     }

 #else
     static SkOpts::TextureCompressor texture_compressor(SkColorType, SkTextureCompressor::Format) {
         return nullptr;
     }
     static bool fill_block_dimensions(SkTextureCompressor::Format, int*, int*) {
         return false;
     }

 #endif

 }  // namespace SK_OPTS_NS

 #endif//SkTextureCompressor_opts_DEFINED
	/*
	* Copyright 2015 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#ifndef SkTextureCompressor_opts_DEFINED
	#define SkTextureCompressor_opts_DEFINED

	#include "SkOpts.h"

	namespace SK_OPTS_NS {

	#if defined(SK_ARM_HAS_NEON)
	// Converts indices in each of the four bits of the register from
	// 0, 1, 2, 3, 4, 5, 6, 7
	// to
	// 3, 2, 1, 0, 4, 5, 6, 7
	//
	// A more detailed explanation can be found in SkTextureCompressor::convert_indices
	static inline uint8x16_t convert_indices(const uint8x16_t &x) {
	static const int8x16_t kThree = {
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	};

	static const int8x16_t kZero = {
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	};

	// Take top three bits
	int8x16_t sx = vreinterpretq_s8_u8(x);

	// Negate ...
	sx = vnegq_s8(sx);

	// Add three...
	sx = vaddq_s8(sx, kThree);

	// Generate negatives mask
	const int8x16_t mask = vreinterpretq_s8_u8(vcltq_s8(sx, kZero));

	// Absolute value
	sx = vabsq_s8(sx);

	// Add three to the values that were negative...
	return vreinterpretq_u8_s8(vaddq_s8(sx, vandq_s8(mask, kThree)));
	}

	template<unsigned shift>
	static inline uint64x2_t shift_swap(const uint64x2_t &x, const uint64x2_t &mask) {
	uint64x2_t t = vandq_u64(mask, veorq_u64(x, vshrq_n_u64(x, shift)));
	return veorq_u64(x, veorq_u64(t, vshlq_n_u64(t, shift)));
	}

	static inline uint64x2_t pack_indices(const uint64x2_t &x) {
	// 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

	static const uint64x2_t kMask1 = { 0x3FC0003FC00000ULL, 0x3FC0003FC00000ULL };
	uint64x2_t ret = shift_swap<10>(x, kMask1);

	// 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
	static const uint64x2_t kMask2 = { (0x3FULL << 52), (0x3FULL << 52) };
	static const uint64x2_t kMask3 = { (0x3FULL << 28), (0x3FULL << 28) };
	const uint64x2_t x1 = vandq_u64(vshlq_n_u64(ret, 52), kMask2);
	const uint64x2_t x2 = vandq_u64(vshlq_n_u64(ret, 20), kMask3);
	ret = vshrq_n_u64(vorrq_u64(ret, vorrq_u64(x1, x2)), 16);

	// 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

	static const uint64x2_t kMask4 = { 0xFC0000ULL, 0xFC0000ULL };
	ret = shift_swap<6>(ret, kMask4);

	#if defined (SK_CPU_BENDIAN)
	// 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

	static const uint64x2_t kMask5 = { 0x3FULL, 0x3FULL };
	ret = shift_swap<36>(ret, kMask5);

	// 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

	static const uint64x2_t kMask6 = { 0xFFF000000ULL, 0xFFF000000ULL };
	ret = shift_swap<12>(ret, kMask6);
	#else
	// 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

	static const uint64x2_t kMask5 = { 0xFC0ULL, 0xFC0ULL };
	ret = shift_swap<36>(ret, kMask5);

	// 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

	static const uint64x2_t kMask6 = { (0xFFFULL << 36), (0xFFFULL << 36) };
	static const uint64x2_t kMask7 = { 0xFFFFFFULL, 0xFFFFFFULL };
	static const uint64x2_t kMask8 = { 0xFFFULL, 0xFFFULL };
	const uint64x2_t y1 = vandq_u64(ret, kMask6);
	const uint64x2_t y2 = vshlq_n_u64(vandq_u64(ret, kMask7), 12);
	const uint64x2_t y3 = vandq_u64(vshrq_n_u64(ret, 24), kMask8);
	ret = vorrq_u64(y1, vorrq_u64(y2, y3));
	#endif

	// 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

	// Set the header
	static const uint64x2_t kHeader = { 0x8490000000000000ULL, 0x8490000000000000ULL };
	return vorrq_u64(kHeader, ret);
	}

	// Takes a row of alpha values and places the most significant three bits of each byte into
	// the least significant bits of the same byte
	static inline uint8x16_t make_index_row(const uint8x16_t &x) {
	static const uint8x16_t kTopThreeMask = {
	0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0,
	0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0, 0xE0,
	};
	return vshrq_n_u8(vandq_u8(x, kTopThreeMask), 5);
	}

	// Returns true if all of the bits in x are 0.
	static inline bool is_zero(uint8x16_t x) {
	// First experiments say that this is way slower than just examining the lanes
	// but it might need a little more investigation.
	#if 0
	// This code path tests the system register for overflow. We trigger
	// overflow by adding x to a register with all of its bits set. The
	// first instruction sets the bits.
	int reg;
	asm ("VTST.8 %%q0, %q1, %q1\n"
	"VQADD.u8 %q1, %%q0\n"
	"VMRS %0, FPSCR\n"
	: "=r"(reg) : "w"(vreinterpretq_f32_u8(x)) : "q0", "q1");

	// Bit 21 corresponds to the overflow flag.
	return reg & (0x1 << 21);
	#else
	const uint64x2_t cvt = vreinterpretq_u64_u8(x);
	const uint64_t l1 = vgetq_lane_u64(cvt, 0);
	return (l1 == 0) && (l1 == vgetq_lane_u64(cvt, 1));
	#endif
	}

	#if defined (SK_CPU_BENDIAN)
	static inline uint64x2_t fix_endianness(uint64x2_t x) {
	return x;
	}
	#else
	static inline uint64x2_t fix_endianness(uint64x2_t x) {
	return vreinterpretq_u64_u8(vrev64q_u8(vreinterpretq_u8_u64(x)));
	}
	#endif

	static void compress_r11eac_blocks(uint8_t* dst, const uint8_t* src, size_t rowBytes) {
	// Try to avoid switching between vector and non-vector ops...
	const uint8_t *const src1 = src;
	const uint8_t *const src2 = src + rowBytes;
	const uint8_t const src3 = src + 2rowBytes;
	const uint8_t const src4 = src + 3rowBytes;
	uint8_t *const dst1 = dst;
	uint8_t *const dst2 = dst + 16;

	const uint8x16_t alphaRow1 = vld1q_u8(src1);
	const uint8x16_t alphaRow2 = vld1q_u8(src2);
	const uint8x16_t alphaRow3 = vld1q_u8(src3);
	const uint8x16_t alphaRow4 = vld1q_u8(src4);

	const uint8x16_t cmp12 = vceqq_u8(alphaRow1, alphaRow2);
	const uint8x16_t cmp34 = vceqq_u8(alphaRow3, alphaRow4);
	const uint8x16_t cmp13 = vceqq_u8(alphaRow1, alphaRow3);

	const uint8x16_t cmp = vandq_u8(vandq_u8(cmp12, cmp34), cmp13);
	const uint8x16_t ncmp = vmvnq_u8(cmp);
	const uint8x16_t nAlphaRow1 = vmvnq_u8(alphaRow1);
	if (is_zero(ncmp)) {
	if (is_zero(alphaRow1)) {
	static const uint64x2_t kTransparent = { 0x0020000000002000ULL,
	0x0020000000002000ULL };
	vst1q_u8(dst1, vreinterpretq_u8_u64(kTransparent));
	vst1q_u8(dst2, vreinterpretq_u8_u64(kTransparent));
	return;
	} else if (is_zero(nAlphaRow1)) {
	vst1q_u8(dst1, cmp);
	vst1q_u8(dst2, cmp);
	return;
	}
	}

	const uint8x16_t indexRow1 = convert_indices(make_index_row(alphaRow1));
	const uint8x16_t indexRow2 = convert_indices(make_index_row(alphaRow2));
	const uint8x16_t indexRow3 = convert_indices(make_index_row(alphaRow3));
	const uint8x16_t indexRow4 = convert_indices(make_index_row(alphaRow4));

	const uint64x2_t indexRow12 = vreinterpretq_u64_u8(
	vorrq_u8(vshlq_n_u8(indexRow1, 3), indexRow2));
	const uint64x2_t indexRow34 = vreinterpretq_u64_u8(
	vorrq_u8(vshlq_n_u8(indexRow3, 3), indexRow4));

	const uint32x4x2_t blockIndices = vtrnq_u32(vreinterpretq_u32_u64(indexRow12),
	vreinterpretq_u32_u64(indexRow34));
	const uint64x2_t blockIndicesLeft = vreinterpretq_u64_u32(vrev64q_u32(blockIndices.val[0]));
	const uint64x2_t blockIndicesRight = vreinterpretq_u64_u32(vrev64q_u32(blockIndices.val[1]));

	const uint64x2_t indicesLeft = fix_endianness(pack_indices(blockIndicesLeft));
	const uint64x2_t indicesRight = fix_endianness(pack_indices(blockIndicesRight));

	const uint64x2_t d1 = vcombine_u64(vget_low_u64(indicesLeft), vget_low_u64(indicesRight));
	const uint64x2_t d2 = vcombine_u64(vget_high_u64(indicesLeft), vget_high_u64(indicesRight));
	vst1q_u8(dst1, vreinterpretq_u8_u64(d1));
	vst1q_u8(dst2, vreinterpretq_u8_u64(d2));
	}

	static bool compress_a8_r11eac(uint8_t* dst, const uint8_t* src,
	int width, int height, size_t rowBytes) {

	// Since we're going to operate on 4 blocks at a time, the src width
	// must be a multiple of 16. However, the height only needs to be a
	// multiple of 4
	if (0 == width \|\| 0 == height \|\| (width % 16) != 0 \|\| (height % 4) != 0) {
	return false;
	}

	const int blocksX = width >> 2;
	const int blocksY = height >> 2;

	SkASSERT((blocksX % 4) == 0);

	for (int y = 0; y < blocksY; ++y) {
	for (int x = 0; x < blocksX; x+=4) {
	// Compress it
	compress_r11eac_blocks(dst, src + 4*x, rowBytes);
	dst += 32;
	}
	src += 4 * rowBytes;
	}
	return true;
	}

	static SkOpts::TextureCompressor texture_compressor(SkColorType ct,
	SkTextureCompressor::Format fmt) {
	if (ct == kAlpha_8_SkColorType && fmt == SkTextureCompressor::kR11_EAC_Format) {
	return compress_a8_r11eac;
	}
	return nullptr;
	}
	static bool fill_block_dimensions(SkTextureCompressor::Format fmt, int* x, int* y) {
	if (fmt == SkTextureCompressor::kR11_EAC_Format) {
	*x = 16;
	*y = 4;
	return true;
	}
	return false;
	}

	#else
	static SkOpts::TextureCompressor texture_compressor(SkColorType, SkTextureCompressor::Format) {
	return nullptr;
	}
	static bool fill_block_dimensions(SkTextureCompressor::Format, int, int) {
	return false;
	}

	#endif

	} // namespace SK_OPTS_NS

	#endif//SkTextureCompressor_opts_DEFINED