#ifndef _LINUX_BITOPS_H
  #define _LINUX_BITOPS_H
  #include <asm/types.h>
  
  #ifdef	__KERNEL__
  #define BIT(nr)			(1UL << (nr))
  #define BIT_ULL(nr)		(1ULL << (nr))
  #define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
  #define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
  #define BIT_ULL_MASK(nr)	(1ULL << ((nr) % BITS_PER_LONG_LONG))
  #define BIT_ULL_WORD(nr)	((nr) / BITS_PER_LONG_LONG)
  #define BITS_PER_BYTE		8
  #define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  #endif
  
  /*
   * Create a contiguous bitmask starting at bit position @l and ending at
   * position @h. For example
   * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
   */
  #define GENMASK(h, l) \
  	(((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
  
  #define GENMASK_ULL(h, l) \
  	(((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
  
  extern unsigned int __sw_hweight8(unsigned int w);
  extern unsigned int __sw_hweight16(unsigned int w);
  extern unsigned int __sw_hweight32(unsigned int w);
  extern unsigned long __sw_hweight64(__u64 w);
  
  /*
   * Include this here because some architectures need generic_ffs/fls in
   * scope
   */
  #include <asm/bitops.h>
  
  #define for_each_set_bit(bit, addr, size) \
  	for ((bit) = find_first_bit((addr), (size));		\
  	     (bit) < (size);					\
  	     (bit) = find_next_bit((addr), (size), (bit) + 1))
  
  /* same as for_each_set_bit() but use bit as value to start with */
  #define for_each_set_bit_from(bit, addr, size) \
  	for ((bit) = find_next_bit((addr), (size), (bit));	\
  	     (bit) < (size);					\
  	     (bit) = find_next_bit((addr), (size), (bit) + 1))
  
  #define for_each_clear_bit(bit, addr, size) \
  	for ((bit) = find_first_zero_bit((addr), (size));	\
  	     (bit) < (size);					\
  	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  
  /* same as for_each_clear_bit() but use bit as value to start with */
  #define for_each_clear_bit_from(bit, addr, size) \
  	for ((bit) = find_next_zero_bit((addr), (size), (bit));	\
  	     (bit) < (size);					\
  	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  
  static __inline__ int get_bitmask_order(unsigned int count)
  {
  	int order;
  
  	order = fls(count);
  	return order;	/* We could be slightly more clever with -1 here... */
  }
  
  static __inline__ int get_count_order(unsigned int count)
  {
  	int order;
  
  	order = fls(count) - 1;
  	if (count & (count - 1))
  		order++;
  	return order;
  }
  
  static inline unsigned long hweight_long(unsigned long w)
  {
  	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  }
  
  /**
   * rol64 - rotate a 64-bit value left
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u64 rol64(__u64 word, unsigned int shift)
  {
  	return (word << shift) | (word >> (64 - shift));
  }
  
  /**
   * ror64 - rotate a 64-bit value right
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u64 ror64(__u64 word, unsigned int shift)
  {
  	return (word >> shift) | (word << (64 - shift));
  }
  
  /**
   * rol32 - rotate a 32-bit value left
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u32 rol32(__u32 word, unsigned int shift)
  {
  	return (word << shift) | (word >> (32 - shift));
  }
  
  /**
   * ror32 - rotate a 32-bit value right
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u32 ror32(__u32 word, unsigned int shift)
  {
  	return (word >> shift) | (word << (32 - shift));
  }
  
  /**
   * rol16 - rotate a 16-bit value left
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u16 rol16(__u16 word, unsigned int shift)
  {
  	return (word << shift) | (word >> (16 - shift));
  }
  
  /**
   * ror16 - rotate a 16-bit value right
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u16 ror16(__u16 word, unsigned int shift)
  {
  	return (word >> shift) | (word << (16 - shift));
  }
  
  /**
   * rol8 - rotate an 8-bit value left
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u8 rol8(__u8 word, unsigned int shift)
  {
  	return (word << shift) | (word >> (8 - shift));
  }
  
  /**
   * ror8 - rotate an 8-bit value right
   * @word: value to rotate
   * @shift: bits to roll
   */
  static inline __u8 ror8(__u8 word, unsigned int shift)
  {
  	return (word >> shift) | (word << (8 - shift));
  }
  
  /**
   * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
   * @value: value to sign extend
   * @index: 0 based bit index (0<=index<32) to sign bit
   */
  static inline __s32 sign_extend32(__u32 value, int index)
  {
  	__u8 shift = 31 - index;
  	return (__s32)(value << shift) >> shift;
  }
  
  static inline unsigned fls_long(unsigned long l)
  {
  	if (sizeof(l) == 4)
  		return fls(l);
  	return fls64(l);
  }
  
  /**
   * __ffs64 - find first set bit in a 64 bit word
   * @word: The 64 bit word
   *
   * On 64 bit arches this is a synomyn for __ffs
   * The result is not defined if no bits are set, so check that @word
   * is non-zero before calling this.
   */
  static inline unsigned long __ffs64(u64 word)
  {
  #if BITS_PER_LONG == 32
  	if (((u32)word) == 0UL)
  		return __ffs((u32)(word >> 32)) + 32;
  #elif BITS_PER_LONG != 64
  #error BITS_PER_LONG not 32 or 64
  #endif
  	return __ffs((unsigned long)word);
  }
  
  #ifdef __KERNEL__
  
  #ifndef set_mask_bits
  #define set_mask_bits(ptr, _mask, _bits)	\
  ({								\
  	const typeof(*ptr) mask = (_mask), bits = (_bits);	\
  	typeof(*ptr) old, new;					\
  								\
  	do {							\
  		old = ACCESS_ONCE(*ptr);			\
  		new = (old & ~mask) | bits;			\
  	} while (cmpxchg(ptr, old, new) != old);		\
  								\
  	new;							\
  })
  #endif
  
  #ifndef find_last_bit
  /**
   * find_last_bit - find the last set bit in a memory region
   * @addr: The address to start the search at
   * @size: The maximum size to search
   *
   * Returns the bit number of the first set bit, or size.
   */
  extern unsigned long find_last_bit(const unsigned long *addr,
  				   unsigned long size);
  #endif
  
  #endif /* __KERNEL__ */
  #endif