bitfield.h File Reference

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Macros
#define	__bf_shf(x)   (__builtin_ffsll(x) - 1)
	These macros come from FreeBSD, check source on https://cgit.freebsd.org/src/tree/sys/compat/linuxkpi/common/include/linux/bitfield.h Which does not include example usages of them. More...
#define	FIELD_FIT(_mask, _value)    (!(((typeof(_mask))(_value) << __bf_shf(_mask)) & ~(_mask)))
	FIELD_FIT(_mask, _value) - Check if a value fits in the specified bitfield mask @_mask: Bitfield mask @_value: Value to check. More...
#define	FIELD_GET(_mask, _value)    ((typeof(_mask))(((_value) & (_mask)) >> __bf_shf(_mask)))
	FIELD_GET(_mask, _value) - Extract a value from a bitfield @_mask: Bitfield mask @_value: Bitfield value to extract from. More...
#define	FIELD_PREP(_mask, _value)    (((typeof(_mask))(_value) << __bf_shf(_mask)) & (_mask))
	FIELD_PREP(_mask, _value) - Prepare a value for insertion into a bitfield @_mask: Bitfield mask @_value: Value to insert. More...

Macro Definition Documentation

__bf_shf

#define __bf_shf

(

x

)

(__builtin_ffsll(x) - 1)

These macros come from FreeBSD, check source on https://cgit.freebsd.org/src/tree/sys/compat/linuxkpi/common/include/linux/bitfield.h Which does not include example usages of them.

Definition at line 19 of file bitfield.h.

FIELD_FIT

#define FIELD_FIT	(		_mask,
			_value
	)		(!(((typeof(_mask))(_value) << __bf_shf(_mask)) & ~(_mask)))

FIELD_FIT(_mask, _value) - Check if a value fits in the specified bitfield mask @_mask: Bitfield mask @_value: Value to check.

This macro checks whether a given value fits within the range defined by the specified bitfield mask. It ensures that no bits outside the mask are set.

Return: true if the value fits, false otherwise.

Definition at line 31 of file bitfield.h.

FIELD_GET

#define FIELD_GET	(		_mask,
			_value
	)		((typeof(_mask))(((_value) & (_mask)) >> __bf_shf(_mask)))

FIELD_GET(_mask, _value) - Extract a value from a bitfield @_mask: Bitfield mask @_value: Bitfield value to extract from.

This macro extracts a value from a bitfield by masking and shifting the relevant bits down to the least significant position.

Return: The extracted value.

Definition at line 57 of file bitfield.h.

FIELD_PREP

#define FIELD_PREP	(		_mask,
			_value
	)		(((typeof(_mask))(_value) << __bf_shf(_mask)) & (_mask))

FIELD_PREP(_mask, _value) - Prepare a value for insertion into a bitfield @_mask: Bitfield mask @_value: Value to insert.

This macro prepares a value for insertion into a bitfield by shifting the value into the position defined by the mask and applying the mask.

Return: The prepared bitfield value.

Definition at line 44 of file bitfield.h.