root/include/linux/bitops.h

INCLUDED FROM

DEFINITIONS

1. get_bitmask_order
2. get_count_order
3. hweight_long
4. rol64
5. ror64
6. rol32
7. ror32
8. rol16
9. ror16
10. rol8
11. ror8
12. sign_extend32
13. fls_long
14. __ffs64

#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