root/include/linux/bitops.h

INCLUDED FROM

DEFINITIONS

1. get_bitmask_order
2. get_count_order
3. hweight_long
4. rol32
5. ror32
6. rol16
7. ror16
8. rol8
9. ror8
10. fls_long

#ifndef _LINUX_BITOPS_H
#define _LINUX_BITOPS_H
#include <asm/types.h>

#ifdef  __KERNEL__
#define BIT(nr)                 (1UL << (nr))
#define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
#define BITS_PER_BYTE           8
#define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
#endif

/*
 * Include this here because some architectures need generic_ffs/fls in
 * scope
 */
#include <asm/bitops.h>

#define for_each_bit(bit, addr, size) \
        for ((bit) = find_first_bit((addr), (size)); \
             (bit) < (size); \
             (bit) = find_next_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);
}

/**
 * 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));
}

static inline unsigned fls_long(unsigned long l)
{
        if (sizeof(l) == 4)
                return fls(l);
        return fls64(l);
}

#ifdef __KERNEL__
#ifdef CONFIG_GENERIC_FIND_FIRST_BIT

/**
 * 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.
 */
extern unsigned long find_first_bit(const unsigned long *addr,
                                    unsigned long 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.
 */
extern unsigned long find_first_zero_bit(const unsigned long *addr,
                                         unsigned long size);

#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */

#ifdef CONFIG_GENERIC_FIND_NEXT_BIT

/**
 * 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
 */
extern 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
 */

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

#endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
#endif /* __KERNEL__ */
#endif