include/bitops.h

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#ifndef BITOPS_H_INCLUDED
#define BITOPS_H_INCLUDED

#include <stdbool.h>
#include <types.h>
#include <assert.h>

#define bit_mask(nr)    (1 << ((nr) & (BITS_PER_LONG - 1)))

#define bit_word(nr)    ((nr) / BITS_PER_LONG)

#include <arch/bitops.h>

static inline void set_bit(unsigned int nr, unsigned long *bitmap)
{
        bitmap[bit_word(nr)] |= bit_mask(nr);
}

static inline void clear_bit(unsigned int nr, unsigned long *bitmap)
{
        bitmap[bit_word(nr)] &= ~bit_mask(nr);
}

static inline void toggle_bit(unsigned int nr, unsigned long *bitmap)
{
        bitmap[bit_word(nr)] ^= bit_mask(nr);
}

static inline bool test_bit(unsigned int nr, unsigned long *bitmap)
{
        return 1UL & (bitmap[bit_word(nr)] >> (nr & (BITS_PER_LONG - 1)));
}

#ifndef extract_aligned_bitfield

static inline uint32_t extract_aligned_bitfield(
                unsigned int start,
                unsigned int length,
                const uint32_t *bitmap)
{
        uint32_t tmp;

        tmp = bitmap[bit_word(start)] >> (start & (BITS_PER_LONG - 1));
        return tmp & ((1 << length) - 1);
}
#endif

static inline uint32_t extract_bitfield(
                unsigned int start,
                unsigned int length,
                const uint32_t *bitmap)
{
        assert(length <= BITS_PER_LONG);

        if (bit_word(start) == bit_word(start + length)) {
                return extract_aligned_bitfield(start, length, bitmap);
        } else {
                unsigned int length_first;
                uint32_t bf_first;
                uint32_t bf_second;

                length_first = BITS_PER_LONG - (start & (BITS_PER_LONG - 1));
                bf_first = extract_aligned_bitfield(start,
                                length_first, bitmap);
                bf_second = extract_aligned_bitfield(start + length_first,
                                length - length_first, bitmap);

                return bf_first | (bf_second << length_first);
        }
}

#endif /* BITOPS_H_INCLUDED */

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