bitops.h

来自「linux 内核源代码」· C头文件 代码 · 共 156 行

#ifndef __ASM_SH_BITOPS_H
#define __ASM_SH_BITOPS_H

#ifdef __KERNEL__

#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif

#include <asm/system.h>
/* For __swab32 */
#include <asm/byteorder.h>

static inline void set_bit(int nr, volatile void * addr)
{
	int	mask;
	volatile unsigned int *a = addr;
	unsigned long flags;

	a += nr >> 5;
	mask = 1 << (nr & 0x1f);
	local_irq_save(flags);
	*a |= mask;
	local_irq_restore(flags);
}

/*
 * clear_bit() doesn't provide any barrier for the compiler.
 */
#define smp_mb__before_clear_bit()	barrier()
#define smp_mb__after_clear_bit()	barrier()
static inline void clear_bit(int nr, volatile void * addr)
{
	int	mask;
	volatile unsigned int *a = addr;
	unsigned long flags;

	a += nr >> 5;
	mask = 1 << (nr & 0x1f);
	local_irq_save(flags);
	*a &= ~mask;
	local_irq_restore(flags);
}

static inline void change_bit(int nr, volatile void * addr)
{
	int	mask;
	volatile unsigned int *a = addr;
	unsigned long flags;

	a += nr >> 5;
	mask = 1 << (nr & 0x1f);
	local_irq_save(flags);
	*a ^= mask;
	local_irq_restore(flags);
}

static inline int test_and_set_bit(int nr, volatile void * addr)
{
	int	mask, retval;
	volatile unsigned int *a = addr;
	unsigned long flags;

	a += nr >> 5;
	mask = 1 << (nr & 0x1f);
	local_irq_save(flags);
	retval = (mask & *a) != 0;
	*a |= mask;
	local_irq_restore(flags);

	return retval;
}

static inline int test_and_clear_bit(int nr, volatile void * addr)
{
	int	mask, retval;
	volatile unsigned int *a = addr;
	unsigned long flags;

	a += nr >> 5;
	mask = 1 << (nr & 0x1f);
	local_irq_save(flags);
	retval = (mask & *a) != 0;
	*a &= ~mask;
	local_irq_restore(flags);

	return retval;
}

static inline int test_and_change_bit(int nr, volatile void * addr)
{
	int	mask, retval;
	volatile unsigned int *a = addr;
	unsigned long flags;

	a += nr >> 5;
	mask = 1 << (nr & 0x1f);
	local_irq_save(flags);
	retval = (mask & *a) != 0;
	*a ^= mask;
	local_irq_restore(flags);

	return retval;
}

#include <asm-generic/bitops/non-atomic.h>

static inline unsigned long ffz(unsigned long word)
{
	unsigned long result;

	__asm__("1:\n\t"
		"shlr	%1\n\t"
		"bt/s	1b\n\t"
		" add	#1, %0"
		: "=r" (result), "=r" (word)
		: "0" (~0L), "1" (word)
		: "t");
	return result;
}

/**
 * __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)
{
	unsigned long result;

	__asm__("1:\n\t"
		"shlr	%1\n\t"
		"bf/s	1b\n\t"
		" add	#1, %0"
		: "=r" (result), "=r" (word)
		: "0" (~0L), "1" (word)
		: "t");
	return result;
}

#include <asm-generic/bitops/find.h>
#include <asm-generic/bitops/ffs.h>
#include <asm-generic/bitops/hweight.h>
#include <asm-generic/bitops/lock.h>
#include <asm-generic/bitops/sched.h>
#include <asm-generic/bitops/ext2-non-atomic.h>
#include <asm-generic/bitops/ext2-atomic.h>
#include <asm-generic/bitops/minix.h>
#include <asm-generic/bitops/fls.h>
#include <asm-generic/bitops/fls64.h>

#endif /* __KERNEL__ */

#endif /* __ASM_SH_BITOPS_H */