include/qemu/bitops.h - third_party/qemu - Git at Google

 /*
  * Bitops Module
  *
  * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
  *
  * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
  *
  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
  * See the COPYING.LIB file in the top-level directory.
  */

 #ifndef BITOPS_H
 #define BITOPS_H


 #include "host-utils.h"
 #include "atomic.h"

 #define BITS_PER_BYTE           CHAR_BIT
 #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)

 #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 BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))

 #define MAKE_64BIT_MASK(shift, length) \
     (((~0ULL) >> (64 - (length))) << (shift))

 /**
  * set_bit - Set a bit in memory
  * @nr: the bit to set
  * @addr: the address to start counting from
  */
 static inline void set_bit(long nr, unsigned long *addr)
 {
     unsigned long mask = BIT_MASK(nr);
     unsigned long *p = addr + BIT_WORD(nr);

     *p  |= mask;
 }

 /**
  * set_bit_atomic - Set a bit in memory atomically
  * @nr: the bit to set
  * @addr: the address to start counting from
  */
 static inline void set_bit_atomic(long nr, unsigned long *addr)
 {
     unsigned long mask = BIT_MASK(nr);
     unsigned long *p = addr + BIT_WORD(nr);

     atomic_or(p, mask);
 }

 /**
  * clear_bit - Clears a bit in memory
  * @nr: Bit to clear
  * @addr: Address to start counting from
  */
 static inline void clear_bit(long nr, unsigned long *addr)
 {
     unsigned long mask = BIT_MASK(nr);
     unsigned long *p = addr + BIT_WORD(nr);

     *p &= ~mask;
 }

 /**
  * change_bit - Toggle a bit in memory
  * @nr: Bit to change
  * @addr: Address to start counting from
  */
 static inline void change_bit(long nr, unsigned long *addr)
 {
     unsigned long mask = BIT_MASK(nr);
     unsigned long *p = addr + BIT_WORD(nr);

     *p ^= mask;
 }

 /**
  * test_and_set_bit - Set a bit and return its old value
  * @nr: Bit to set
  * @addr: Address to count from
  */
 static inline int test_and_set_bit(long nr, unsigned long *addr)
 {
     unsigned long mask = BIT_MASK(nr);
     unsigned long *p = addr + BIT_WORD(nr);
     unsigned long old = *p;

     *p = old | mask;
     return (old & mask) != 0;
 }

 /**
  * test_and_clear_bit - Clear a bit and return its old value
  * @nr: Bit to clear
  * @addr: Address to count from
  */
 static inline int test_and_clear_bit(long nr, unsigned long *addr)
 {
     unsigned long mask = BIT_MASK(nr);
     unsigned long *p = addr + BIT_WORD(nr);
     unsigned long old = *p;

     *p = old & ~mask;
     return (old & mask) != 0;
 }

 /**
  * test_and_change_bit - Change a bit and return its old value
  * @nr: Bit to change
  * @addr: Address to count from
  */
 static inline int test_and_change_bit(long nr, unsigned long *addr)
 {
     unsigned long mask = BIT_MASK(nr);
     unsigned long *p = addr + BIT_WORD(nr);
     unsigned long old = *p;

     *p = old ^ mask;
     return (old & mask) != 0;
 }

 /**
  * test_bit - Determine whether a bit is set
  * @nr: bit number to test
  * @addr: Address to start counting from
  */
 static inline int test_bit(long nr, const unsigned long *addr)
 {
     return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
 }

 /**
  * 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.
  */
 unsigned long find_last_bit(const unsigned long *addr,
                             unsigned long size);

 /**
  * find_next_bit - find the next set bit in a memory region
  * @addr: The address to base the search on
  * @offset: The bitnumber to start searching at
  * @size: The bitmap size in bits
  */
 unsigned long find_next_bit(const unsigned long *addr,
                             unsigned long size,
                             unsigned long offset);

 /**
  * find_next_zero_bit - find the next cleared bit in a memory region
  * @addr: The address to base the search on
  * @offset: The bitnumber to start searching at
  * @size: The bitmap size in bits
  */

 unsigned long find_next_zero_bit(const unsigned long *addr,
                                  unsigned long size,
                                  unsigned long offset);

 /**
  * find_first_bit - find the first 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.
  */
 static inline unsigned long find_first_bit(const unsigned long *addr,
                                            unsigned long size)
 {
     unsigned long result, tmp;

     for (result = 0; result < size; result += BITS_PER_LONG) {
         tmp = *addr++;
         if (tmp) {
             result += ctzl(tmp);
             return result < size ? result : size;
         }
     }
     /* Not found */
     return size;
 }

 /**
  * find_first_zero_bit - find the first cleared 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 cleared bit.
  */
 static inline unsigned long find_first_zero_bit(const unsigned long *addr,
                                                 unsigned long size)
 {
     return find_next_zero_bit(addr, size, 0);
 }

 /**
  * rol8 - rotate an 8-bit value left
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint8_t rol8(uint8_t word, unsigned int shift)
 {
     return (word << shift) | (word >> ((8 - shift) & 7));
 }

 /**
  * ror8 - rotate an 8-bit value right
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint8_t ror8(uint8_t word, unsigned int shift)
 {
     return (word >> shift) | (word << ((8 - shift) & 7));
 }

 /**
  * rol16 - rotate a 16-bit value left
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint16_t rol16(uint16_t word, unsigned int shift)
 {
     return (word << shift) | (word >> ((16 - shift) & 15));
 }

 /**
  * ror16 - rotate a 16-bit value right
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint16_t ror16(uint16_t word, unsigned int shift)
 {
     return (word >> shift) | (word << ((16 - shift) & 15));
 }

 /**
  * rol32 - rotate a 32-bit value left
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint32_t rol32(uint32_t word, unsigned int shift)
 {
     return (word << shift) | (word >> ((32 - shift) & 31));
 }

 /**
  * ror32 - rotate a 32-bit value right
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint32_t ror32(uint32_t word, unsigned int shift)
 {
     return (word >> shift) | (word << ((32 - shift) & 31));
 }

 /**
  * rol64 - rotate a 64-bit value left
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint64_t rol64(uint64_t word, unsigned int shift)
 {
     return (word << shift) | (word >> ((64 - shift) & 63));
 }

 /**
  * ror64 - rotate a 64-bit value right
  * @word: value to rotate
  * @shift: bits to roll
  */
 static inline uint64_t ror64(uint64_t word, unsigned int shift)
 {
     return (word >> shift) | (word << ((64 - shift) & 63));
 }

 /**
  * extract32:
  * @value: the value to extract the bit field from
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  *
  * Extract from the 32 bit input @value the bit field specified by the
  * @start and @length parameters, and return it. The bit field must
  * lie entirely within the 32 bit word. It is valid to request that
  * all 32 bits are returned (ie @length 32 and @start 0).
  *
  * Returns: the value of the bit field extracted from the input value.
  */
 static inline uint32_t extract32(uint32_t value, int start, int length)
 {
     assert(start >= 0 && length > 0 && length <= 32 - start);
     return (value >> start) & (~0U >> (32 - length));
 }

 /**
  * extract8:
  * @value: the value to extract the bit field from
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  *
  * Extract from the 8 bit input @value the bit field specified by the
  * @start and @length parameters, and return it. The bit field must
  * lie entirely within the 8 bit word. It is valid to request that
  * all 8 bits are returned (ie @length 8 and @start 0).
  *
  * Returns: the value of the bit field extracted from the input value.
  */
 static inline uint8_t extract8(uint8_t value, int start, int length)
 {
     assert(start >= 0 && length > 0 && length <= 8 - start);
     return extract32(value, start, length);
 }

 /**
  * extract16:
  * @value: the value to extract the bit field from
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  *
  * Extract from the 16 bit input @value the bit field specified by the
  * @start and @length parameters, and return it. The bit field must
  * lie entirely within the 16 bit word. It is valid to request that
  * all 16 bits are returned (ie @length 16 and @start 0).
  *
  * Returns: the value of the bit field extracted from the input value.
  */
 static inline uint16_t extract16(uint16_t value, int start, int length)
 {
     assert(start >= 0 && length > 0 && length <= 16 - start);
     return extract32(value, start, length);
 }

 /**
  * extract64:
  * @value: the value to extract the bit field from
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  *
  * Extract from the 64 bit input @value the bit field specified by the
  * @start and @length parameters, and return it. The bit field must
  * lie entirely within the 64 bit word. It is valid to request that
  * all 64 bits are returned (ie @length 64 and @start 0).
  *
  * Returns: the value of the bit field extracted from the input value.
  */
 static inline uint64_t extract64(uint64_t value, int start, int length)
 {
     assert(start >= 0 && length > 0 && length <= 64 - start);
     return (value >> start) & (~0ULL >> (64 - length));
 }

 /**
  * sextract32:
  * @value: the value to extract the bit field from
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  *
  * Extract from the 32 bit input @value the bit field specified by the
  * @start and @length parameters, and return it, sign extended to
  * an int32_t (ie with the most significant bit of the field propagated
  * to all the upper bits of the return value). The bit field must lie
  * entirely within the 32 bit word. It is valid to request that
  * all 32 bits are returned (ie @length 32 and @start 0).
  *
  * Returns: the sign extended value of the bit field extracted from the
  * input value.
  */
 static inline int32_t sextract32(uint32_t value, int start, int length)
 {
     assert(start >= 0 && length > 0 && length <= 32 - start);
     /* Note that this implementation relies on right shift of signed
      * integers being an arithmetic shift.
      */
     return ((int32_t)(value << (32 - length - start))) >> (32 - length);
 }

 /**
  * sextract64:
  * @value: the value to extract the bit field from
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  *
  * Extract from the 64 bit input @value the bit field specified by the
  * @start and @length parameters, and return it, sign extended to
  * an int64_t (ie with the most significant bit of the field propagated
  * to all the upper bits of the return value). The bit field must lie
  * entirely within the 64 bit word. It is valid to request that
  * all 64 bits are returned (ie @length 64 and @start 0).
  *
  * Returns: the sign extended value of the bit field extracted from the
  * input value.
  */
 static inline int64_t sextract64(uint64_t value, int start, int length)
 {
     assert(start >= 0 && length > 0 && length <= 64 - start);
     /* Note that this implementation relies on right shift of signed
      * integers being an arithmetic shift.
      */
     return ((int64_t)(value << (64 - length - start))) >> (64 - length);
 }

 /**
  * deposit32:
  * @value: initial value to insert bit field into
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  * @fieldval: the value to insert into the bit field
  *
  * Deposit @fieldval into the 32 bit @value at the bit field specified
  * by the @start and @length parameters, and return the modified
  * @value. Bits of @value outside the bit field are not modified.
  * Bits of @fieldval above the least significant @length bits are
  * ignored. The bit field must lie entirely within the 32 bit word.
  * It is valid to request that all 32 bits are modified (ie @length
  * 32 and @start 0).
  *
  * Returns: the modified @value.
  */
 static inline uint32_t deposit32(uint32_t value, int start, int length,
                                  uint32_t fieldval)
 {
     uint32_t mask;
     assert(start >= 0 && length > 0 && length <= 32 - start);
     mask = (~0U >> (32 - length)) << start;
     return (value & ~mask) | ((fieldval << start) & mask);
 }

 /**
  * deposit64:
  * @value: initial value to insert bit field into
  * @start: the lowest bit in the bit field (numbered from 0)
  * @length: the length of the bit field
  * @fieldval: the value to insert into the bit field
  *
  * Deposit @fieldval into the 64 bit @value at the bit field specified
  * by the @start and @length parameters, and return the modified
  * @value. Bits of @value outside the bit field are not modified.
  * Bits of @fieldval above the least significant @length bits are
  * ignored. The bit field must lie entirely within the 64 bit word.
  * It is valid to request that all 64 bits are modified (ie @length
  * 64 and @start 0).
  *
  * Returns: the modified @value.
  */
 static inline uint64_t deposit64(uint64_t value, int start, int length,
                                  uint64_t fieldval)
 {
     uint64_t mask;
     assert(start >= 0 && length > 0 && length <= 64 - start);
     mask = (~0ULL >> (64 - length)) << start;
     return (value & ~mask) | ((fieldval << start) & mask);
 }

 /**
  * half_shuffle32:
  * @x: 32-bit value (of which only the bottom 16 bits are of interest)
  *
  * Given an input value::
  *
  *   xxxx xxxx xxxx xxxx ABCD EFGH IJKL MNOP
  *
  * return the value where the bottom 16 bits are spread out into
  * the odd bits in the word, and the even bits are zeroed::
  *
  *   0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N 0O0P
  *
  * Any bits set in the top half of the input are ignored.
  *
  * Returns: the shuffled bits.
  */
 static inline uint32_t half_shuffle32(uint32_t x)
 {
     /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
      * It ignores any bits set in the top half of the input.
      */
     x = ((x & 0xFF00) << 8) | (x & 0x00FF);
     x = ((x << 4) | x) & 0x0F0F0F0F;
     x = ((x << 2) | x) & 0x33333333;
     x = ((x << 1) | x) & 0x55555555;
     return x;
 }

 /**
  * half_shuffle64:
  * @x: 64-bit value (of which only the bottom 32 bits are of interest)
  *
  * Given an input value::
  *
  *   xxxx xxxx xxxx .... xxxx xxxx ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
  *
  * return the value where the bottom 32 bits are spread out into
  * the odd bits in the word, and the even bits are zeroed::
  *
  *   0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N .... 0U0V 0W0X 0Y0Z 0a0b 0c0d 0e0f
  *
  * Any bits set in the top half of the input are ignored.
  *
  * Returns: the shuffled bits.
  */
 static inline uint64_t half_shuffle64(uint64_t x)
 {
     /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
      * It ignores any bits set in the top half of the input.
      */
     x = ((x & 0xFFFF0000ULL) << 16) | (x & 0xFFFF);
     x = ((x << 8) | x) & 0x00FF00FF00FF00FFULL;
     x = ((x << 4) | x) & 0x0F0F0F0F0F0F0F0FULL;
     x = ((x << 2) | x) & 0x3333333333333333ULL;
     x = ((x << 1) | x) & 0x5555555555555555ULL;
     return x;
 }

 /**
  * half_unshuffle32:
  * @x: 32-bit value (of which only the odd bits are of interest)
  *
  * Given an input value::
  *
  *   xAxB xCxD xExF xGxH xIxJ xKxL xMxN xOxP
  *
  * return the value where all the odd bits are compressed down
  * into the low half of the word, and the high half is zeroed::
  *
  *   0000 0000 0000 0000 ABCD EFGH IJKL MNOP
  *
  * Any even bits set in the input are ignored.
  *
  * Returns: the unshuffled bits.
  */
 static inline uint32_t half_unshuffle32(uint32_t x)
 {
     /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
      * where it is called an inverse half shuffle.
      */
     x &= 0x55555555;
     x = ((x >> 1) | x) & 0x33333333;
     x = ((x >> 2) | x) & 0x0F0F0F0F;
     x = ((x >> 4) | x) & 0x00FF00FF;
     x = ((x >> 8) | x) & 0x0000FFFF;
     return x;
 }

 /**
  * half_unshuffle64:
  * @x: 64-bit value (of which only the odd bits are of interest)
  *
  * Given an input value::
  *
  *   xAxB xCxD xExF xGxH xIxJ xKxL xMxN .... xUxV xWxX xYxZ xaxb xcxd xexf
  *
  * return the value where all the odd bits are compressed down
  * into the low half of the word, and the high half is zeroed::
  *
  *   0000 0000 0000 .... 0000 0000 ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
  *
  * Any even bits set in the input are ignored.
  *
  * Returns: the unshuffled bits.
  */
 static inline uint64_t half_unshuffle64(uint64_t x)
 {
     /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
      * where it is called an inverse half shuffle.
      */
     x &= 0x5555555555555555ULL;
     x = ((x >> 1) | x) & 0x3333333333333333ULL;
     x = ((x >> 2) | x) & 0x0F0F0F0F0F0F0F0FULL;
     x = ((x >> 4) | x) & 0x00FF00FF00FF00FFULL;
     x = ((x >> 8) | x) & 0x0000FFFF0000FFFFULL;
     x = ((x >> 16) | x) & 0x00000000FFFFFFFFULL;
     return x;
 }

 #endif
	/*
	* Bitops Module
	*
	* Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
	*
	* Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
	*
	* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
	* See the COPYING.LIB file in the top-level directory.
	*/

	#ifndef BITOPS_H
	#define BITOPS_H


	#include "host-utils.h"
	#include "atomic.h"

	#define BITS_PER_BYTE CHAR_BIT
	#define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE)

	#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 BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))

	#define MAKE_64BIT_MASK(shift, length) \
	(((~0ULL) >> (64 - (length))) << (shift))

	/**
	* set_bit - Set a bit in memory
	* @nr: the bit to set
	* @addr: the address to start counting from
	*/
	static inline void set_bit(long nr, unsigned long *addr)
	{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = addr + BIT_WORD(nr);

	*p \|= mask;
	}

	/**
	* set_bit_atomic - Set a bit in memory atomically
	* @nr: the bit to set
	* @addr: the address to start counting from
	*/
	static inline void set_bit_atomic(long nr, unsigned long *addr)
	{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = addr + BIT_WORD(nr);

	atomic_or(p, mask);
	}

	/**
	* clear_bit - Clears a bit in memory
	* @nr: Bit to clear
	* @addr: Address to start counting from
	*/
	static inline void clear_bit(long nr, unsigned long *addr)
	{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = addr + BIT_WORD(nr);

	*p &= ~mask;
	}

	/**
	* change_bit - Toggle a bit in memory
	* @nr: Bit to change
	* @addr: Address to start counting from
	*/
	static inline void change_bit(long nr, unsigned long *addr)
	{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = addr + BIT_WORD(nr);

	*p ^= mask;
	}

	/**
	* test_and_set_bit - Set a bit and return its old value
	* @nr: Bit to set
	* @addr: Address to count from
	*/
	static inline int test_and_set_bit(long nr, unsigned long *addr)
	{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = addr + BIT_WORD(nr);
	unsigned long old = *p;

	*p = old \| mask;
	return (old & mask) != 0;
	}

	/**
	* test_and_clear_bit - Clear a bit and return its old value
	* @nr: Bit to clear
	* @addr: Address to count from
	*/
	static inline int test_and_clear_bit(long nr, unsigned long *addr)
	{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = addr + BIT_WORD(nr);
	unsigned long old = *p;

	*p = old & ~mask;
	return (old & mask) != 0;
	}

	/**
	* test_and_change_bit - Change a bit and return its old value
	* @nr: Bit to change
	* @addr: Address to count from
	*/
	static inline int test_and_change_bit(long nr, unsigned long *addr)
	{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = addr + BIT_WORD(nr);
	unsigned long old = *p;

	*p = old ^ mask;
	return (old & mask) != 0;
	}

	/**
	* test_bit - Determine whether a bit is set
	* @nr: bit number to test
	* @addr: Address to start counting from
	*/
	static inline int test_bit(long nr, const unsigned long *addr)
	{
	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
	}

	/**
	* 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.
	*/
	unsigned long find_last_bit(const unsigned long *addr,
	unsigned long size);

	/**
	* find_next_bit - find the next set bit in a memory region
	* @addr: The address to base the search on
	* @offset: The bitnumber to start searching at
	* @size: The bitmap size in bits
	*/
	unsigned long find_next_bit(const unsigned long *addr,
	unsigned long size,
	unsigned long offset);

	/**
	* find_next_zero_bit - find the next cleared bit in a memory region
	* @addr: The address to base the search on
	* @offset: The bitnumber to start searching at
	* @size: The bitmap size in bits
	*/

	unsigned long find_next_zero_bit(const unsigned long *addr,
	unsigned long size,
	unsigned long offset);

	/**
	* find_first_bit - find the first 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.
	*/
	static inline unsigned long find_first_bit(const unsigned long *addr,
	unsigned long size)
	{
	unsigned long result, tmp;

	for (result = 0; result < size; result += BITS_PER_LONG) {
	tmp = *addr++;
	if (tmp) {
	result += ctzl(tmp);
	return result < size ? result : size;
	}
	}
	/* Not found */
	return size;
	}

	/**
	* find_first_zero_bit - find the first cleared 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 cleared bit.
	*/
	static inline unsigned long find_first_zero_bit(const unsigned long *addr,
	unsigned long size)
	{
	return find_next_zero_bit(addr, size, 0);
	}

	/**
	* rol8 - rotate an 8-bit value left
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint8_t rol8(uint8_t word, unsigned int shift)
	{
	return (word << shift) \| (word >> ((8 - shift) & 7));
	}

	/**
	* ror8 - rotate an 8-bit value right
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint8_t ror8(uint8_t word, unsigned int shift)
	{
	return (word >> shift) \| (word << ((8 - shift) & 7));
	}

	/**
	* rol16 - rotate a 16-bit value left
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint16_t rol16(uint16_t word, unsigned int shift)
	{
	return (word << shift) \| (word >> ((16 - shift) & 15));
	}

	/**
	* ror16 - rotate a 16-bit value right
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint16_t ror16(uint16_t word, unsigned int shift)
	{
	return (word >> shift) \| (word << ((16 - shift) & 15));
	}

	/**
	* rol32 - rotate a 32-bit value left
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint32_t rol32(uint32_t word, unsigned int shift)
	{
	return (word << shift) \| (word >> ((32 - shift) & 31));
	}

	/**
	* ror32 - rotate a 32-bit value right
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint32_t ror32(uint32_t word, unsigned int shift)
	{
	return (word >> shift) \| (word << ((32 - shift) & 31));
	}

	/**
	* rol64 - rotate a 64-bit value left
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint64_t rol64(uint64_t word, unsigned int shift)
	{
	return (word << shift) \| (word >> ((64 - shift) & 63));
	}

	/**
	* ror64 - rotate a 64-bit value right
	* @word: value to rotate
	* @shift: bits to roll
	*/
	static inline uint64_t ror64(uint64_t word, unsigned int shift)
	{
	return (word >> shift) \| (word << ((64 - shift) & 63));
	}

	/**
	* extract32:
	* @value: the value to extract the bit field from
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	*
	* Extract from the 32 bit input @value the bit field specified by the
	* @start and @length parameters, and return it. The bit field must
	* lie entirely within the 32 bit word. It is valid to request that
	* all 32 bits are returned (ie @length 32 and @start 0).
	*
	* Returns: the value of the bit field extracted from the input value.
	*/
	static inline uint32_t extract32(uint32_t value, int start, int length)
	{
	assert(start >= 0 && length > 0 && length <= 32 - start);
	return (value >> start) & (~0U >> (32 - length));
	}

	/**
	* extract8:
	* @value: the value to extract the bit field from
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	*
	* Extract from the 8 bit input @value the bit field specified by the
	* @start and @length parameters, and return it. The bit field must
	* lie entirely within the 8 bit word. It is valid to request that
	* all 8 bits are returned (ie @length 8 and @start 0).
	*
	* Returns: the value of the bit field extracted from the input value.
	*/
	static inline uint8_t extract8(uint8_t value, int start, int length)
	{
	assert(start >= 0 && length > 0 && length <= 8 - start);
	return extract32(value, start, length);
	}

	/**
	* extract16:
	* @value: the value to extract the bit field from
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	*
	* Extract from the 16 bit input @value the bit field specified by the
	* @start and @length parameters, and return it. The bit field must
	* lie entirely within the 16 bit word. It is valid to request that
	* all 16 bits are returned (ie @length 16 and @start 0).
	*
	* Returns: the value of the bit field extracted from the input value.
	*/
	static inline uint16_t extract16(uint16_t value, int start, int length)
	{
	assert(start >= 0 && length > 0 && length <= 16 - start);
	return extract32(value, start, length);
	}

	/**
	* extract64:
	* @value: the value to extract the bit field from
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	*
	* Extract from the 64 bit input @value the bit field specified by the
	* @start and @length parameters, and return it. The bit field must
	* lie entirely within the 64 bit word. It is valid to request that
	* all 64 bits are returned (ie @length 64 and @start 0).
	*
	* Returns: the value of the bit field extracted from the input value.
	*/
	static inline uint64_t extract64(uint64_t value, int start, int length)
	{
	assert(start >= 0 && length > 0 && length <= 64 - start);
	return (value >> start) & (~0ULL >> (64 - length));
	}

	/**
	* sextract32:
	* @value: the value to extract the bit field from
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	*
	* Extract from the 32 bit input @value the bit field specified by the
	* @start and @length parameters, and return it, sign extended to
	* an int32_t (ie with the most significant bit of the field propagated
	* to all the upper bits of the return value). The bit field must lie
	* entirely within the 32 bit word. It is valid to request that
	* all 32 bits are returned (ie @length 32 and @start 0).
	*
	* Returns: the sign extended value of the bit field extracted from the
	* input value.
	*/
	static inline int32_t sextract32(uint32_t value, int start, int length)
	{
	assert(start >= 0 && length > 0 && length <= 32 - start);
	/* Note that this implementation relies on right shift of signed
	* integers being an arithmetic shift.
	*/
	return ((int32_t)(value << (32 - length - start))) >> (32 - length);
	}

	/**
	* sextract64:
	* @value: the value to extract the bit field from
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	*
	* Extract from the 64 bit input @value the bit field specified by the
	* @start and @length parameters, and return it, sign extended to
	* an int64_t (ie with the most significant bit of the field propagated
	* to all the upper bits of the return value). The bit field must lie
	* entirely within the 64 bit word. It is valid to request that
	* all 64 bits are returned (ie @length 64 and @start 0).
	*
	* Returns: the sign extended value of the bit field extracted from the
	* input value.
	*/
	static inline int64_t sextract64(uint64_t value, int start, int length)
	{
	assert(start >= 0 && length > 0 && length <= 64 - start);
	/* Note that this implementation relies on right shift of signed
	* integers being an arithmetic shift.
	*/
	return ((int64_t)(value << (64 - length - start))) >> (64 - length);
	}

	/**
	* deposit32:
	* @value: initial value to insert bit field into
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	* @fieldval: the value to insert into the bit field
	*
	* Deposit @fieldval into the 32 bit @value at the bit field specified
	* by the @start and @length parameters, and return the modified
	* @value. Bits of @value outside the bit field are not modified.
	* Bits of @fieldval above the least significant @length bits are
	* ignored. The bit field must lie entirely within the 32 bit word.
	* It is valid to request that all 32 bits are modified (ie @length
	* 32 and @start 0).
	*
	* Returns: the modified @value.
	*/
	static inline uint32_t deposit32(uint32_t value, int start, int length,
	uint32_t fieldval)
	{
	uint32_t mask;
	assert(start >= 0 && length > 0 && length <= 32 - start);
	mask = (~0U >> (32 - length)) << start;
	return (value & ~mask) \| ((fieldval << start) & mask);
	}

	/**
	* deposit64:
	* @value: initial value to insert bit field into
	* @start: the lowest bit in the bit field (numbered from 0)
	* @length: the length of the bit field
	* @fieldval: the value to insert into the bit field
	*
	* Deposit @fieldval into the 64 bit @value at the bit field specified
	* by the @start and @length parameters, and return the modified
	* @value. Bits of @value outside the bit field are not modified.
	* Bits of @fieldval above the least significant @length bits are
	* ignored. The bit field must lie entirely within the 64 bit word.
	* It is valid to request that all 64 bits are modified (ie @length
	* 64 and @start 0).
	*
	* Returns: the modified @value.
	*/
	static inline uint64_t deposit64(uint64_t value, int start, int length,
	uint64_t fieldval)
	{
	uint64_t mask;
	assert(start >= 0 && length > 0 && length <= 64 - start);
	mask = (~0ULL >> (64 - length)) << start;
	return (value & ~mask) \| ((fieldval << start) & mask);
	}

	/**
	* half_shuffle32:
	* @x: 32-bit value (of which only the bottom 16 bits are of interest)
	*
	* Given an input value::
	*
	* xxxx xxxx xxxx xxxx ABCD EFGH IJKL MNOP
	*
	* return the value where the bottom 16 bits are spread out into
	* the odd bits in the word, and the even bits are zeroed::
	*
	* 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N 0O0P
	*
	* Any bits set in the top half of the input are ignored.
	*
	* Returns: the shuffled bits.
	*/
	static inline uint32_t half_shuffle32(uint32_t x)
	{
	/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
	* It ignores any bits set in the top half of the input.
	*/
	x = ((x & 0xFF00) << 8) \| (x & 0x00FF);
	x = ((x << 4) \| x) & 0x0F0F0F0F;
	x = ((x << 2) \| x) & 0x33333333;
	x = ((x << 1) \| x) & 0x55555555;
	return x;
	}

	/**
	* half_shuffle64:
	* @x: 64-bit value (of which only the bottom 32 bits are of interest)
	*
	* Given an input value::
	*
	* xxxx xxxx xxxx .... xxxx xxxx ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
	*
	* return the value where the bottom 32 bits are spread out into
	* the odd bits in the word, and the even bits are zeroed::
	*
	* 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N .... 0U0V 0W0X 0Y0Z 0a0b 0c0d 0e0f
	*
	* Any bits set in the top half of the input are ignored.
	*
	* Returns: the shuffled bits.
	*/
	static inline uint64_t half_shuffle64(uint64_t x)
	{
	/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
	* It ignores any bits set in the top half of the input.
	*/
	x = ((x & 0xFFFF0000ULL) << 16) \| (x & 0xFFFF);
	x = ((x << 8) \| x) & 0x00FF00FF00FF00FFULL;
	x = ((x << 4) \| x) & 0x0F0F0F0F0F0F0F0FULL;
	x = ((x << 2) \| x) & 0x3333333333333333ULL;
	x = ((x << 1) \| x) & 0x5555555555555555ULL;
	return x;
	}

	/**
	* half_unshuffle32:
	* @x: 32-bit value (of which only the odd bits are of interest)
	*
	* Given an input value::
	*
	* xAxB xCxD xExF xGxH xIxJ xKxL xMxN xOxP
	*
	* return the value where all the odd bits are compressed down
	* into the low half of the word, and the high half is zeroed::
	*
	* 0000 0000 0000 0000 ABCD EFGH IJKL MNOP
	*
	* Any even bits set in the input are ignored.
	*
	* Returns: the unshuffled bits.
	*/
	static inline uint32_t half_unshuffle32(uint32_t x)
	{
	/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
	* where it is called an inverse half shuffle.
	*/
	x &= 0x55555555;
	x = ((x >> 1) \| x) & 0x33333333;
	x = ((x >> 2) \| x) & 0x0F0F0F0F;
	x = ((x >> 4) \| x) & 0x00FF00FF;
	x = ((x >> 8) \| x) & 0x0000FFFF;
	return x;
	}

	/**
	* half_unshuffle64:
	* @x: 64-bit value (of which only the odd bits are of interest)
	*
	* Given an input value::
	*
	* xAxB xCxD xExF xGxH xIxJ xKxL xMxN .... xUxV xWxX xYxZ xaxb xcxd xexf
	*
	* return the value where all the odd bits are compressed down
	* into the low half of the word, and the high half is zeroed::
	*
	* 0000 0000 0000 .... 0000 0000 ABCD EFGH IJKL MNOP QRST UVWX YZab cdef
	*
	* Any even bits set in the input are ignored.
	*
	* Returns: the unshuffled bits.
	*/
	static inline uint64_t half_unshuffle64(uint64_t x)
	{
	/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits".
	* where it is called an inverse half shuffle.
	*/
	x &= 0x5555555555555555ULL;
	x = ((x >> 1) \| x) & 0x3333333333333333ULL;
	x = ((x >> 2) \| x) & 0x0F0F0F0F0F0F0F0FULL;
	x = ((x >> 4) \| x) & 0x00FF00FF00FF00FFULL;
	x = ((x >> 8) \| x) & 0x0000FFFF0000FFFFULL;
	x = ((x >> 16) \| x) & 0x00000000FFFFFFFFULL;
	return x;
	}

	#endif