bitops.h

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#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

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);
}

static inline __u64 rol64(__u64 word, unsigned int shift)
{
    return (word << shift) | (word >> (64 - shift));
}

static inline __u64 ror64(__u64 word, unsigned int shift)
{
    return (word >> shift) | (word << (64 - shift));
}

static inline __u32 rol32(__u32 word, unsigned int shift)
{
    return (word << shift) | (word >> (32 - shift));
}

static inline __u32 ror32(__u32 word, unsigned int shift)
{
    return (word >> shift) | (word << (32 - shift));
}

static inline __u16 rol16(__u16 word, unsigned int shift)
{
    return (word << shift) | (word >> (16 - shift));
}

static inline __u16 ror16(__u16 word, unsigned int shift)
{
    return (word >> shift) | (word << (16 - shift));
}

static inline __u8 rol8(__u8 word, unsigned int shift)
{
    return (word << shift) | (word >> (8 - shift));
}

static inline __u8 ror8(__u8 word, unsigned int shift)
{
    return (word >> shift) | (word << (8 - shift));
}

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);
}

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 find_last_bit

extern unsigned long find_last_bit(const unsigned long *addr,
                   unsigned long size);
#endif

#endif /* __KERNEL__ */
#endif