#ifndef _LINUX_MATH64_H
  #define _LINUX_MATH64_H
  
  #include <linux/types.h>
  #include <asm/div64.h>
  
  #if BITS_PER_LONG == 64

  #define div64_long(x, y) div64_s64((x), (y))
  #define div64_ul(x, y)   div64_u64((x), (y))

  /**
   * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder
   *
   * This is commonly provided by 32bit archs to provide an optimized 64bit
   * divide.
   */
  static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
  {
  	*remainder = dividend % divisor;
  	return dividend / divisor;
  }
  
  /**
   * div_s64_rem - signed 64bit divide with 32bit divisor with remainder
   */
  static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
  {
  	*remainder = dividend % divisor;
  	return dividend / divisor;
  }

  /**

   * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder
   */
  static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder)
  {
  	*remainder = dividend % divisor;
  	return dividend / divisor;
  }
  
  /**

   * div64_u64 - unsigned 64bit divide with 64bit divisor
   */
  static inline u64 div64_u64(u64 dividend, u64 divisor)
  {
  	return dividend / divisor;
  }

  /**
   * div64_s64 - signed 64bit divide with 64bit divisor
   */
  static inline s64 div64_s64(s64 dividend, s64 divisor)
  {
  	return dividend / divisor;
  }

  #elif BITS_PER_LONG == 32

  #define div64_long(x, y) div_s64((x), (y))
  #define div64_ul(x, y)   div_u64((x), (y))

  #ifndef div_u64_rem
  static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
  {
  	*remainder = do_div(dividend, divisor);
  	return dividend;
  }
  #endif
  
  #ifndef div_s64_rem
  extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder);
  #endif

  #ifndef div64_u64_rem
  extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder);
  #endif

  #ifndef div64_u64

  extern u64 div64_u64(u64 dividend, u64 divisor);

  #endif

  #ifndef div64_s64
  extern s64 div64_s64(s64 dividend, s64 divisor);
  #endif

  #endif /* BITS_PER_LONG */
  
  /**
   * div_u64 - unsigned 64bit divide with 32bit divisor
   *
   * This is the most common 64bit divide and should be used if possible,
   * as many 32bit archs can optimize this variant better than a full 64bit
   * divide.
   */
  #ifndef div_u64
  static inline u64 div_u64(u64 dividend, u32 divisor)
  {
  	u32 remainder;
  	return div_u64_rem(dividend, divisor, &remainder);
  }
  #endif
  
  /**
   * div_s64 - signed 64bit divide with 32bit divisor
   */
  #ifndef div_s64
  static inline s64 div_s64(s64 dividend, s32 divisor)
  {
  	s32 remainder;
  	return div_s64_rem(dividend, divisor, &remainder);
  }
  #endif

  u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);

  static __always_inline u32
  __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
  {
  	u32 ret = 0;
  
  	while (dividend >= divisor) {
  		/* The following asm() prevents the compiler from
  		   optimising this loop into a modulo operation.  */
  		asm("" : "+rm"(dividend));
  
  		dividend -= divisor;
  		ret++;
  	}
  
  	*remainder = dividend;
  
  	return ret;
  }

  #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
  
  #ifndef mul_u64_u32_shr
  static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
  {
  	return (u64)(((unsigned __int128)a * mul) >> shift);
  }
  #endif /* mul_u64_u32_shr */

  #ifndef mul_u64_u64_shr
  static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
  {
  	return (u64)(((unsigned __int128)a * mul) >> shift);
  }
  #endif /* mul_u64_u64_shr */

  #else
  
  #ifndef mul_u64_u32_shr
  static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
  {
  	u32 ah, al;
  	u64 ret;
  
  	al = a;
  	ah = a >> 32;
  
  	ret = ((u64)al * mul) >> shift;
  	if (ah)
  		ret += ((u64)ah * mul) << (32 - shift);
  
  	return ret;
  }
  #endif /* mul_u64_u32_shr */

  #ifndef mul_u64_u64_shr
  static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
  {
  	union {
  		u64 ll;
  		struct {
  #ifdef __BIG_ENDIAN
  			u32 high, low;
  #else
  			u32 low, high;
  #endif
  		} l;
  	} rl, rm, rn, rh, a0, b0;
  	u64 c;
  
  	a0.ll = a;
  	b0.ll = b;
  
  	rl.ll = (u64)a0.l.low * b0.l.low;
  	rm.ll = (u64)a0.l.low * b0.l.high;
  	rn.ll = (u64)a0.l.high * b0.l.low;
  	rh.ll = (u64)a0.l.high * b0.l.high;
  
  	/*
  	 * Each of these lines computes a 64-bit intermediate result into "c",
  	 * starting at bits 32-95.  The low 32-bits go into the result of the
  	 * multiplication, the high 32-bits are carried into the next step.
  	 */
  	rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low;
  	rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low;
  	rh.l.high = (c >> 32) + rh.l.high;
  
  	/*
  	 * The 128-bit result of the multiplication is in rl.ll and rh.ll,
  	 * shift it right and throw away the high part of the result.
  	 */
  	if (shift == 0)
  		return rl.ll;
  	if (shift < 64)
  		return (rl.ll >> shift) | (rh.ll << (64 - shift));
  	return rh.ll >> (shift & 63);
  }
  #endif /* mul_u64_u64_shr */

  #endif

  #ifndef mul_u64_u32_div
  static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
  {
  	union {
  		u64 ll;
  		struct {
  #ifdef __BIG_ENDIAN
  			u32 high, low;
  #else
  			u32 low, high;
  #endif
  		} l;
  	} u, rl, rh;
  
  	u.ll = a;
  	rl.ll = (u64)u.l.low * mul;
  	rh.ll = (u64)u.l.high * mul + rl.l.high;
  
  	/* Bits 32-63 of the result will be in rh.l.low. */
  	rl.l.high = do_div(rh.ll, divisor);
  
  	/* Bits 0-31 of the result will be in rl.l.low.	*/
  	do_div(rl.ll, divisor);
  
  	rl.l.high = rh.l.low;
  	return rl.ll;
  }
  #endif /* mul_u64_u32_div */

  #endif /* _LINUX_MATH64_H */