Bit Manipulation Functions

Files
file	ARCH-amd64/bitops_arch.h
	amd64 bit manipulation functions
file	ARCH-x86/bitops_arch.h
	x86 bit manipulation functions
file	bitops.h
	bit manipulation functions
Functions
void	l4util_set_bit (int b, volatile l4_umword_t *dest)
	Set bit in memory.
void	l4util_clear_bit (int b, volatile l4_umword_t *dest)
	Clear bit in memory.
void	l4util_complement_bit (int b, volatile l4_umword_t *dest)
	Complement bit in memory.
int	l4util_test_bit (int b, const volatile l4_umword_t *dest)
	Test bit (return value of bit).
int	l4util_bts (int b, volatile l4_umword_t *dest)
	Bit test and set.
int	l4util_btr (int b, volatile l4_umword_t *dest)
	Bit test and reset.
int	l4util_btc (int b, volatile l4_umword_t *dest)
	Bit test and complement.
int	l4util_bsr (l4_umword_t word)
	Bit scan reverse.
int	l4util_bsf (l4_umword_t word)
	Bit scan forward.
int	l4util_find_first_set_bit (const void *dest, l4_size_t size)
	Find the first set bit in a memory region.
int	l4util_find_first_zero_bit (const void *dest, l4_size_t size)
	Find the first zero bit in a memory region.

---

Function Documentation

void l4util_set_bit	(	int	b,
		volatile l4_umword_t *	dest
	)			[inline]

Set bit in memory.

Parameters:

	b	bit position
	dest	destination operand

Definition at line 74 of file ARCH-amd64/bitops_arch.h.

void l4util_clear_bit	(	int	b,
		volatile l4_umword_t *	dest
	)			[inline]

Clear bit in memory.

Parameters:

	b	bit position
	dest	destination operand

Definition at line 114 of file ARCH-amd64/bitops_arch.h.

void l4util_complement_bit	(	int	b,
		volatile l4_umword_t *	dest
	)			[inline]

Complement bit in memory.

Parameters:

	b	bit position
	dest	destination operand

Definition at line 122 of file ARCH-amd64/bitops_arch.h.

int l4util_test_bit	(	int	b,
		const volatile l4_umword_t *	dest
	)			[inline]

Test bit (return value of bit).

Parameters:

	b	bit position
	dest	destination operand

Returns:

Value of bit b.

Definition at line 183 of file ARCH-amd64/bitops_arch.h.

int l4util_bts	(	int	b,
		volatile l4_umword_t *	dest
	)			[inline]

Bit test and set.

Parameters:

	b	bit position
	dest	destination operand

Returns:

Old value of bit b.

Set the b bit of dest to 1 and return the old value.

Definition at line 192 of file ARCH-amd64/bitops_arch.h.

int l4util_btr	(	int	b,
		volatile l4_umword_t *	dest
	)			[inline]

Bit test and reset.

Parameters:

	b	bit position
	dest	destination operand

Returns:

Old value of bit b.

Reset bit b and return old value.

Definition at line 215 of file ARCH-amd64/bitops_arch.h.

int l4util_btc	(	int	b,
		volatile l4_umword_t *	dest
	)			[inline]

Bit test and complement.

Parameters:

	b	bit position
	dest	destination operand

Returns:

Old value of bit b.

Complement bit b and return old value.

Definition at line 238 of file ARCH-amd64/bitops_arch.h.

int l4util_bsr

(

l4_umword_t

word

)

[inline]

Bit scan reverse.

Parameters:

word

value (machine size)

Returns:

index of most significant set bit in word, -1 if no bit is set (word == 0)

"bit scan reverse", find most significant set bit in word (-> LOG2(word))

Definition at line 261 of file ARCH-amd64/bitops_arch.h.

int l4util_bsf

(

l4_umword_t

word

)

[inline]

Bit scan forward.

Parameters:

word

value (machine size)

Returns:

index of least significant bit set in word, -1 if no bit is set (word == 0)

"bit scan forward", find least significant bit set in word.

Definition at line 283 of file ARCH-amd64/bitops_arch.h.

int l4util_find_first_set_bit	(	const void *	dest,
		l4_size_t	size
	)			[inline]

Find the first set bit in a memory region.

Parameters:

	dest	bitstring
	size	size of string in bits (must be a multiple of 32!)

Returns:

number of the first set bit, >= size if no bit is set

Definition at line 304 of file ARCH-amd64/bitops_arch.h.

int l4util_find_first_zero_bit	(	const void *	dest,
		l4_size_t	size
	)			[inline]

Find the first zero bit in a memory region.

Parameters:

	dest	bitstring
	size	size of string in bits (must be a multiple of 32!)

Returns:

number of the first zero bit, >= size if no bit is set

Definition at line 331 of file ARCH-amd64/bitops_arch.h.