/*

This file is copied from the Linux kernel and mildly adjusted for use in userspace

*/

#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_

#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_

#define BITOP_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))

#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)

/**

 * __set_bit - Set a bit in memory

 * @nr: the bit to set

 * @addr: the address to start counting from

 *

 * Unlike set_bit(), this function is non-atomic and may be reordered.

 * If it's called on the same region of memory simultaneously, the effect

 * may be that only one operation succeeds.

 */

static inline void set_bit(int nr, volatile unsigned long *addr)

{

	unsigned long mask = BITOP_MASK(nr);

	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);

	*p  |= mask;

}

static inline void clear_bit(int nr, volatile unsigned long *addr)

{

	unsigned long mask = BITOP_MASK(nr);

	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);

	*p &= ~mask;

}

/**

 * __change_bit - Toggle a bit in memory

 * @nr: the bit to change

 * @addr: the address to start counting from

 *

 * Unlike change_bit(), this function is non-atomic and may be reordered.

 * If it's called on the same region of memory simultaneously, the effect

 * may be that only one operation succeeds.

 */

static inline void __change_bit(int nr, volatile unsigned long *addr)

{

	unsigned long mask = BITOP_MASK(nr);

	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);

	*p ^= mask;

}

/**

 * __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(int nr, volatile unsigned long *addr)

{

	unsigned long mask = BITOP_MASK(nr);

	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);

	unsigned long old = *p;

	*p = old | mask;

	return (old & mask) != 0;

}

/**

 * __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(int nr, volatile unsigned long *addr)

{

	unsigned long mask = BITOP_MASK(nr);

	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);

	unsigned long old = *p;

	*p = old & ~mask;

	return (old & mask) != 0;

}

/* WARNING: non atomic and it can be reordered! */

static inline int __test_and_change_bit(int nr,

					    volatile unsigned long *addr)

{

	unsigned long mask = BITOP_MASK(nr);

	unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);

	unsigned long old = *p;

	*p = old ^ mask;

	return (old & mask) != 0;

}

/**

 * test_bit - Determine whether a bit is set

 * @nr: bit number to test

 * @addr: Address to start counting from

 */

static inline int test_bit(int nr, const volatile unsigned long *addr)

{

	return 1UL & (addr[BITOP_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));

}

#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */