regfield.h File Reference

Macros to help dealing with register fields. More...

#include <sys/cdefs.h>

Go to the source code of this file.

Macros
#define	BIT(bit)
	Create a mask with a bit set.
#define	GENMASK(h, l)
	Create a mask with a range of bits set.
#define	FIELD_GET(var, field)
	Extract a field value from a variable.
#define	FIELD_PREP(field, value)
	Prepare a field with a given value.

Detailed Description

Macros to help dealing with register fields.

Author

Paul Cercueil

Macro Definition Documentation

BIT

#define BIT

(

bit

)

Value:

(1u << (bit))

Create a mask with a bit set.

Parameters

bit	The bit to set (from 0 to 31)

Returns

A 32-bit mask with the corresponding bit set

FIELD_GET

#define FIELD_GET	(		var,
			field )

Value:

        (((var) & (field)) >> __builtin_ctz(field))

Extract a field value from a variable.

Parameters

var	The 32-bit variable containing the field
field	A 32-bit mask that corresponds to the field

Returns

The value of the field (shifted)

FIELD_PREP

#define FIELD_PREP	(		field,
			value )

Value:

        (((value) << __builtin_ctz(field)) & (field))

Prepare a field with a given value.

Parameters

field	A 32-bit mask that corresponds to the field
value	The value to be put in the field

GENMASK

#define GENMASK	(		h,
			l )

Value:

((0xffffffff << (l)) & (0xffffffff >> (31 - (h))))

Create a mask with a range of bits set.

Parameters

h	The high bit of the range to set, included
l	The low bit of the range to set, included

Returns

A 32-bit mask with the corresponding bits set