text: /*
   * 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 SkUtils_opts_DEFINED
  #define SkUtils_opts_DEFINED
  
  namespace SK_OPTS_NS {
  
  #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
  
  static void memset16(uint16_t* dst, uint16_t val, int n) {
      auto dst8 = (__m128i*)dst;
      auto val8 = _mm_set1_epi16(val);
      for ( ; n >= 8; n -= 8) {
          _mm_storeu_si128(dst8++, val8);
      }
      dst = (uint16_t*)dst8;
      if (n & 4) {
          _mm_storel_epi64((__m128i*)dst, val8);
          dst += 4;
      }
      if (n & 2) {
          *(uint32_t*)dst = _mm_cvtsi128_si32(val8);
          dst += 2;
      }
      if (n & 1) {
          *dst = val;
      }
  }
  
  static void memset32(uint32_t* dst, uint32_t val, int n) {
      auto dst4 = (__m128i*)dst;
      auto val4 = _mm_set1_epi32(val);
      for ( ; n >= 4; n -= 4) {
          _mm_storeu_si128(dst4++, val4);
      }
      dst = (uint32_t*)dst4;
      if (n & 2) {
          _mm_storel_epi64((__m128i*)dst, val4);
          dst += 2;
      }
      if (n & 1) {
          *dst = val;
      }
  }
  
  #elif defined(SK_ARM_HAS_NEON)
  
  static void memset16(uint16_t* dst, uint16_t value, int n) {
      uint16x8_t   v8  = vdupq_n_u16(value);
      uint16x8x4_t v32 = {{ v8, v8, v8, v8 }};
  
      while (n >= 32) {
          vst4q_u16(dst, v32);  // This swizzles, but we don't care: all lanes are the same, value.
          dst += 32;
          n   -= 32;
      }
      switch (n / 8) {
          case 3: vst1q_u16(dst, v8); dst += 8;
          case 2: vst1q_u16(dst, v8); dst += 8;
          case 1: vst1q_u16(dst, v8); dst += 8;
      }
      if (n & 4) {
          vst1_u16(dst, vget_low_u16(v8));
          dst += 4;
      }
      switch (n & 3) {
          case 3: *dst++ = value;
          case 2: *dst++ = value;
          case 1: *dst   = value;
      }
  }
  
  static void memset32(uint32_t* dst, uint32_t value, int n) {
      uint32x4_t   v4  = vdupq_n_u32(value);
      uint32x4x4_t v16 = {{ v4, v4, v4, v4 }};
  
      while (n >= 16) {
          vst4q_u32(dst, v16);  // This swizzles, but we don't care: all lanes are the same, value.
          dst += 16;
          n   -= 16;
      }
      switch (n / 4) {
          case 3: vst1q_u32(dst, v4); dst += 4;
          case 2: vst1q_u32(dst, v4); dst += 4;
          case 1: vst1q_u32(dst, v4); dst += 4;
      }
      if (n & 2) {
          vst1_u32(dst, vget_low_u32(v4));
          dst += 2;
      }
      if (n & 1) {
          *dst = value;
      }
  }
  
  #else // Neither NEON nor SSE2.
  
  static void memset16(uint16_t* dst, uint16_t val, int n) { while (n --> 0) { *dst++ = val; } }
  static void memset32(uint32_t* dst, uint32_t val, int n) { while (n --> 0) { *dst++ = val; } }
  
  #endif
  
  }  // namespace SK_OPTS_NS
  
  #endif//SkUtils_opts_DEFINED
  