include/asm-generic/bitops/ops.h

#ifndef _ASM_GENERIC_BITOPS_OPS_H_
#define _ASM_GENERIC_BITOPS_OPS_H_

#include <asm/types.h>

/**
 * __set_bit - Set a bit in memory
 * @nr: the bit to set
 * @addr: the address to start counting from
 */
static inline void __set_bit(int nr, volatile unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);

	*p  |= mask;
}

static inline void __clear_bit(int nr, volatile unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);

	*p &= ~mask;
}

/**
 * __change_bit - Toggle a bit in memory
 * @nr: the bit to change
 * @addr: the address to start counting from
 */
static inline void __change_bit(int nr, volatile unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_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
 */
static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_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
 */
static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
	unsigned long old = *p;

	*p = old & ~mask;
	return (old & mask) != 0;
}

static inline int __test_and_change_bit(int nr,
					    volatile unsigned long *addr)
{
	unsigned long mask = BIT_MASK(nr);
	unsigned long *p = ((unsigned long *)addr) + BIT_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[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
}

#endif /* _ASM_GENERIC_BITOPS_OPS_H_ */