bitops.h

来自「Linux Kernel 2.6.9 for OMAP1710」· C头文件 代码 · 共 961 行 · 第 1/2 页

	int retval;
	__bi_flags;

	a += nr >> SZLONG_LOG;
	mask = 1 << (nr & SZLONG_MASK);
	__bi_local_irq_save(flags);
	retval = (mask & *a) != 0;
	*a |= mask;
	__bi_local_irq_restore(flags);

	return retval;
}

/*
 * __test_and_set_bit - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 *
 * This operation is non-atomic and can be reordered.
 * If two examples of this operation race, one can appear to succeed
 * but actually fail.  You must protect multiple accesses with a lock.
 */
static inline int __test_and_set_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask;
	int retval;

	a += nr >> SZLONG_LOG;
	mask = 1 << (nr & SZLONG_MASK);
	retval = (mask & *a) != 0;
	*a |= mask;

	return retval;
}

/*
 * test_and_clear_bit - Clear a bit and return its old value
 * @nr: Bit to clear
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_clear_bit(unsigned long nr,
	volatile unsigned long * addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask;
	int retval;
	__bi_flags;

	a += nr >> SZLONG_LOG;
	mask = 1 << (nr & SZLONG_MASK);
	__bi_local_irq_save(flags);
	retval = (mask & *a) != 0;
	*a &= ~mask;
	__bi_local_irq_restore(flags);

	return retval;
}

/*
 * __test_and_clear_bit - Clear a bit and return its old value
 * @nr: Bit to clear
 * @addr: Address to count from
 *
 * This operation is non-atomic and can be reordered.
 * If two examples of this operation race, one can appear to succeed
 * but actually fail.  You must protect multiple accesses with a lock.
 */
static inline int __test_and_clear_bit(unsigned long nr,
	volatile unsigned long * addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask;
	int retval;

	a += (nr >> SZLONG_LOG);
	mask = 1UL << (nr & SZLONG_MASK);
	retval = ((mask & *a) != 0);
	*a &= ~mask;

	return retval;
}

/*
 * test_and_change_bit - Change a bit and return its old value
 * @nr: Bit to change
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_change_bit(unsigned long nr,
	volatile unsigned long * addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask, retval;
	__bi_flags;

	a += nr >> SZLONG_LOG;
	mask = 1 << (nr & SZLONG_MASK);
	__bi_local_irq_save(flags);
	retval = (mask & *a) != 0;
	*a ^= mask;
	__bi_local_irq_restore(flags);

	return retval;
}

/*
 * __test_and_change_bit - Change a bit and return its old value
 * @nr: Bit to change
 * @addr: Address to count from
 *
 * This operation is non-atomic and can be reordered.
 * If two examples of this operation race, one can appear to succeed
 * but actually fail.  You must protect multiple accesses with a lock.
 */
static inline int __test_and_change_bit(unsigned long nr,
	volatile unsigned long * addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask;
	int retval;

	a += (nr >> SZLONG_LOG);
	mask = 1 << (nr & SZLONG_MASK);
	retval = (mask & *a) != 0;
	*a ^= mask;

	return retval;
}

#undef __bi_flags
#undef __bi_cli
#undef __bi_save_flags
#undef __bi_local_irq_restore

#endif /* MIPS I */

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

/*
 * ffz - find first zero in word.
 * @word: The word to search
 *
 * Undefined if no zero exists, so code should check against ~0UL first.
 */
static inline unsigned long ffz(unsigned long word)
{
	int b = 0, s;

	word = ~word;
#ifdef CONFIG_MIPS32
	s = 16; if (word << 16 != 0) s = 0; b += s; word >>= s;
	s =  8; if (word << 24 != 0) s = 0; b += s; word >>= s;
	s =  4; if (word << 28 != 0) s = 0; b += s; word >>= s;
	s =  2; if (word << 30 != 0) s = 0; b += s; word >>= s;
	s =  1; if (word << 31 != 0) s = 0; b += s;
#endif
#ifdef CONFIG_MIPS64
	s = 32; if (word << 32 != 0) s = 0; b += s; word >>= s;
	s = 16; if (word << 48 != 0) s = 0; b += s; word >>= s;
	s =  8; if (word << 56 != 0) s = 0; b += s; word >>= s;
	s =  4; if (word << 60 != 0) s = 0; b += s; word >>= s;
	s =  2; if (word << 62 != 0) s = 0; b += s; word >>= s;
	s =  1; if (word << 63 != 0) s = 0; b += s;
#endif

	return b;
}

/*
 * __ffs - find first bit in word.
 * @word: The word to search
 *
 * Undefined if no bit exists, so code should check against 0 first.
 */
static inline unsigned long __ffs(unsigned long word)
{
	return ffz(~word);
}

/*
 * fls: find last bit set.
 */

#define fls(x) generic_fls(x)

/*
 * find_next_zero_bit - find the first zero bit in a memory region
 * @addr: The address to base the search on
 * @offset: The bitnumber to start searching at
 * @size: The maximum size to search
 */
static inline unsigned long find_next_zero_bit(const unsigned long *addr,
	unsigned long size, unsigned long offset)
{
	const unsigned long *p = addr + (offset >> SZLONG_LOG);
	unsigned long result = offset & ~SZLONG_MASK;
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= SZLONG_MASK;
	if (offset) {
		tmp = *(p++);
		tmp |= ~0UL >> (_MIPS_SZLONG-offset);
		if (size < _MIPS_SZLONG)
			goto found_first;
		if (~tmp)
			goto found_middle;
		size -= _MIPS_SZLONG;
		result += _MIPS_SZLONG;
	}
	while (size & ~SZLONG_MASK) {
		if (~(tmp = *(p++)))
			goto found_middle;
		result += _MIPS_SZLONG;
		size -= _MIPS_SZLONG;
	}
	if (!size)
		return result;
	tmp = *p;

found_first:
	tmp |= ~0UL << size;
	if (tmp == ~0UL)		/* Are any bits zero? */
		return result + size;	/* Nope. */
found_middle:
	return result + ffz(tmp);
}

#define find_first_zero_bit(addr, size) \
	find_next_zero_bit((addr), (size), 0)

/*
 * 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 maximum size to search
 */
static inline unsigned long find_next_bit(const unsigned long *addr,
	unsigned long size, unsigned long offset)
{
	const unsigned long *p = addr + (offset >> SZLONG_LOG);
	unsigned long result = offset & ~SZLONG_MASK;
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= SZLONG_MASK;
	if (offset) {
		tmp = *(p++);
		tmp &= ~0UL << offset;
		if (size < _MIPS_SZLONG)
			goto found_first;
		if (tmp)
			goto found_middle;
		size -= _MIPS_SZLONG;
		result += _MIPS_SZLONG;
	}
	while (size & ~SZLONG_MASK) {
		if ((tmp = *(p++)))
			goto found_middle;
		result += _MIPS_SZLONG;
		size -= _MIPS_SZLONG;
	}
	if (!size)
		return result;
	tmp = *p;

found_first:
	tmp &= ~0UL >> (_MIPS_SZLONG - size);
	if (tmp == 0UL)			/* Are any bits set? */
		return result + size;	/* Nope. */
found_middle:
	return result + __ffs(tmp);
}

/*
 * 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, not the number of the byte
 * containing a bit.
 */
#define find_first_bit(addr, size) \
	find_next_bit((addr), (size), 0)

#ifdef __KERNEL__

/*
 * Every architecture must define this function. It's the fastest
 * way of searching a 140-bit bitmap where the first 100 bits are
 * unlikely to be set. It's guaranteed that at least one of the 140
 * bits is cleared.
 */
static inline int sched_find_first_bit(const unsigned long *b)
{
#ifdef CONFIG_MIPS32
	if (unlikely(b[0]))
		return __ffs(b[0]);
	if (unlikely(b[1]))
		return __ffs(b[1]) + 32;
	if (unlikely(b[2]))
		return __ffs(b[2]) + 64;
	if (b[3])
		return __ffs(b[3]) + 96;
	return __ffs(b[4]) + 128;
#endif
#ifdef CONFIG_MIPS64
	if (unlikely(b[0]))
		return __ffs(b[0]);
	if (unlikely(b[1]))
		return __ffs(b[1]) + 64;
	return __ffs(b[2]) + 128;
#endif
}

/*
 * ffs - find first bit set
 * @x: the word to search
 *
 * This is defined the same way as
 * the libc and compiler builtin ffs routines, therefore
 * differs in spirit from the above ffz (man ffs).
 */

#define ffs(x) generic_ffs(x)

/*
 * hweightN - returns the hamming weight of a N-bit word
 * @x: the word to weigh
 *
 * The Hamming Weight of a number is the total number of bits set in it.
 */

#define hweight64(x)	generic_hweight64(x)
#define hweight32(x)	generic_hweight32(x)
#define hweight16(x)	generic_hweight16(x)
#define hweight8(x)	generic_hweight8(x)

static inline int __test_and_set_le_bit(unsigned long nr, unsigned long *addr)
{
	unsigned char	*ADDR = (unsigned char *) addr;
	int		mask, retval;

	ADDR += nr >> 3;
	mask = 1 << (nr & 0x07);
	retval = (mask & *ADDR) != 0;
	*ADDR |= mask;

	return retval;
}

static inline int __test_and_clear_le_bit(unsigned long nr, unsigned long *addr)
{
	unsigned char	*ADDR = (unsigned char *) addr;
	int		mask, retval;

	ADDR += nr >> 3;
	mask = 1 << (nr & 0x07);
	retval = (mask & *ADDR) != 0;
	*ADDR &= ~mask;

	return retval;
}

static inline int test_le_bit(unsigned long nr, const unsigned long * addr)
{
	const unsigned char	*ADDR = (const unsigned char *) addr;
	int			mask;

	ADDR += nr >> 3;
	mask = 1 << (nr & 0x07);

	return ((mask & *ADDR) != 0);
}

static inline unsigned long find_next_zero_le_bit(unsigned long *addr,
	unsigned long size, unsigned long offset)
{
	unsigned long *p = ((unsigned long *) addr) + (offset >> SZLONG_LOG);
	unsigned long result = offset & ~SZLONG_MASK;
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= SZLONG_MASK;
	if (offset) {
		tmp = cpu_to_lelongp(p++);
		tmp |= ~0UL >> (_MIPS_SZLONG-offset); /* bug or feature ? */
		if (size < _MIPS_SZLONG)
			goto found_first;
		if (~tmp)
			goto found_middle;
		size -= _MIPS_SZLONG;
		result += _MIPS_SZLONG;
	}
	while (size & ~SZLONG_MASK) {
		if (~(tmp = cpu_to_lelongp(p++)))
			goto found_middle;
		result += _MIPS_SZLONG;
		size -= _MIPS_SZLONG;
	}
	if (!size)
		return result;
	tmp = cpu_to_lelongp(p);

found_first:
	tmp |= ~0UL << size;
	if (tmp == ~0UL)		/* Are any bits zero? */
		return result + size;	/* Nope. */

found_middle:
	return result + ffz(tmp);
}

#define find_first_zero_le_bit(addr, size) \
	find_next_zero_le_bit((addr), (size), 0)

#define ext2_set_bit(nr,addr) \
	__test_and_set_le_bit((nr),(unsigned long*)addr)
#define ext2_clear_bit(nr, addr) \
	__test_and_clear_le_bit((nr),(unsigned long*)addr)
 #define ext2_set_bit_atomic(lock, nr, addr)		\
({							\
	int ret;					\
	spin_lock(lock);				\
	ret = ext2_set_bit((nr), (addr));		\
	spin_unlock(lock);				\
	ret;						\
})

#define ext2_clear_bit_atomic(lock, nr, addr)		\
({							\
	int ret;					\
	spin_lock(lock);				\
	ret = ext2_clear_bit((nr), (addr));		\
	spin_unlock(lock);				\
	ret;						\
})
#define ext2_test_bit(nr, addr)	test_le_bit((nr),(unsigned long*)addr)
#define ext2_find_first_zero_bit(addr, size) \
	find_first_zero_le_bit((unsigned long*)addr, size)
#define ext2_find_next_zero_bit(addr, size, off) \
	find_next_zero_le_bit((unsigned long*)addr, size, off)

/*
 * Bitmap functions for the minix filesystem.
 *
 * FIXME: These assume that Minix uses the native byte/bitorder.
 * This limits the Minix filesystem's value for data exchange very much.
 */
#define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
#define minix_set_bit(nr,addr) set_bit(nr,addr)
#define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
#define minix_test_bit(nr,addr) test_bit(nr,addr)
#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)

#endif /* __KERNEL__ */

#endif /* _ASM_BITOPS_H */