size_t neon_count_16(const char16_t *input, size_t length) {
  size_t count{0};
  size_t pos{0};
  uint16x8_t low  = vmovq_n_u16(0xDC00);
  uint16x8_t high = vmovq_n_u16(0xDFFF);
  
  while(pos + 8 < length) {
    size_t next_stop = pos + (length - pos > 0xFFFFF ? 0xFFFFF : length - pos);
    uint16x8_t counter = vdupq_n_u16(0);
    for(;pos + 8 < next_stop; pos += 8) {
      uint16x8_t in = vld1q_u16(reinterpret_cast<const uint16_t*>(input + pos));
      counter = vsubq_s16(counter,vorrq_u16(vcgtq_u16(in,high), vcltq_u16(in,low)));
    }
    count += vpaddd_u64(vpaddlq_u32(vpaddlq_u16(counter)));
  }
  return count + scalar::utf16::count_code_points(input + pos, length - pos);

}