linux/include/linux/bitfield.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2014 Felix Fietkau <[email protected]>
 * Copyright (C) 2004 - 2009 Ivo van Doorn <[email protected]>
 */

#ifndef _LINUX_BITFIELD_H
#define _LINUX_BITFIELD_H

#include <linux/build_bug.h>
#include <asm/byteorder.h>

/*
 * Bitfield access macros
 *
 * FIELD_{GET,PREP} macros take as first parameter shifted mask
 * from which they extract the base mask and shift amount.
 * Mask must be a compilation time constant.
 *
 * Example:
 *
 *  #include <linux/bitfield.h>
 *  #include <linux/bits.h>
 *
 *  #define REG_FIELD_A  GENMASK(6, 0)
 *  #define REG_FIELD_B  BIT(7)
 *  #define REG_FIELD_C  GENMASK(15, 8)
 *  #define REG_FIELD_D  GENMASK(31, 16)
 *
 * Get:
 *  a = FIELD_GET(REG_FIELD_A, reg);
 *  b = FIELD_GET(REG_FIELD_B, reg);
 *
 * Set:
 *  reg = FIELD_PREP(REG_FIELD_A, 1) |
 *	  FIELD_PREP(REG_FIELD_B, 0) |
 *	  FIELD_PREP(REG_FIELD_C, c) |
 *	  FIELD_PREP(REG_FIELD_D, 0x40);
 *
 * Modify:
 *  reg &= ~REG_FIELD_C;
 *  reg |= FIELD_PREP(REG_FIELD_C, c);
 */

#define __bf_shf(x) …

#define __scalar_type_to_unsigned_cases(type) …

#define __unsigned_scalar_typeof(x) …

#define __bf_cast_unsigned(type, x) …

#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) …

/**
 * FIELD_MAX() - produce the maximum value representable by a field
 * @_mask: shifted mask defining the field's length and position
 *
 * FIELD_MAX() returns the maximum value that can be held in the field
 * specified by @_mask.
 */
#define FIELD_MAX(_mask) …

/**
 * FIELD_FIT() - check if value fits in the field
 * @_mask: shifted mask defining the field's length and position
 * @_val:  value to test against the field
 *
 * Return: true if @_val can fit inside @_mask, false if @_val is too big.
 */
#define FIELD_FIT(_mask, _val) …

/**
 * FIELD_PREP() - prepare a bitfield element
 * @_mask: shifted mask defining the field's length and position
 * @_val:  value to put in the field
 *
 * FIELD_PREP() masks and shifts up the value.  The result should
 * be combined with other fields of the bitfield using logical OR.
 */
#define FIELD_PREP(_mask, _val) …

#define __BF_CHECK_POW2(n) …

/**
 * FIELD_PREP_CONST() - prepare a constant bitfield element
 * @_mask: shifted mask defining the field's length and position
 * @_val:  value to put in the field
 *
 * FIELD_PREP_CONST() masks and shifts up the value.  The result should
 * be combined with other fields of the bitfield using logical OR.
 *
 * Unlike FIELD_PREP() this is a constant expression and can therefore
 * be used in initializers. Error checking is less comfortable for this
 * version, and non-constant masks cannot be used.
 */
#define FIELD_PREP_CONST(_mask, _val) …

/**
 * FIELD_GET() - extract a bitfield element
 * @_mask: shifted mask defining the field's length and position
 * @_reg:  value of entire bitfield
 *
 * FIELD_GET() extracts the field specified by @_mask from the
 * bitfield passed in as @_reg by masking and shifting it down.
 */
#define FIELD_GET(_mask, _reg) …

extern void __compiletime_error("value doesn't fit into mask")
__field_overflow(void);
extern void __compiletime_error("bad bitfield mask")
__bad_mask(void);
static __always_inline u64 field_multiplier(u64 field)
{ … }
static __always_inline u64 field_mask(u64 field)
{ … }
#define field_max(field) …
#define ____MAKE_OP …
#define __MAKE_OP …
____MAKE_OP(u8,u8,,)
__MAKE_OP
__MAKE_OP
__MAKE_OP
#undef __MAKE_OP
#undef ____MAKE_OP

#endif