forked from auracaster/openocd
Walter Ji
e30828a276
This patch ports FIELD_{GET,PREP,FIT} macros and related macro
from FreeBSD, referenced file:
- `src/tree/sys/compat/linuxkpi/common/include/linux/bitfield.h`
Checkpatch-ignore: MACRO_ARG_REUSE
Change-Id: I6fdf4514d3f95d62fadf7654409a4878d470a600
Signed-off-by: Walter Ji <walter.ji@oss.cipunited.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8171
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/*
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* Copyright (c) 2020-2024 The FreeBSD Foundation
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*
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* This software was developed by Björn Zeeb under sponsorship from
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* the FreeBSD Foundation.
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*/
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#ifndef OPENOCD_HELPER_BITFIELD_H
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#define OPENOCD_HELPER_BITFIELD_H
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/**
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* These macros come from FreeBSD, check source on
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* https://cgit.freebsd.org/src/tree/sys/compat/linuxkpi/common/include/linux/bitfield.h
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* Which does not include example usages of them.
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*/
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#define __bf_shf(x) (__builtin_ffsll(x) - 1)
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/**
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* FIELD_FIT(_mask, _value) - Check if a value fits in the specified bitfield mask
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* @_mask: Bitfield mask
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* @_value: Value to check
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*
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* This macro checks whether a given value fits within the range defined by the
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* specified bitfield mask. It ensures that no bits outside the mask are set.
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*
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* Return: true if the value fits, false otherwise.
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*/
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#define FIELD_FIT(_mask, _value) \
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(!(((typeof(_mask))(_value) << __bf_shf(_mask)) & ~(_mask)))
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/**
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* FIELD_PREP(_mask, _value) - Prepare a value for insertion into a bitfield
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* @_mask: Bitfield mask
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* @_value: Value to insert
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*
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* This macro prepares a value for insertion into a bitfield by shifting the
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* value into the position defined by the mask and applying the mask.
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*
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* Return: The prepared bitfield value.
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*/
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#define FIELD_PREP(_mask, _value) \
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(((typeof(_mask))(_value) << __bf_shf(_mask)) & (_mask))
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/**
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* FIELD_GET(_mask, _value) - Extract a value from a bitfield
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* @_mask: Bitfield mask
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* @_value: Bitfield value to extract from
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*
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* This macro extracts a value from a bitfield by masking and shifting the
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* relevant bits down to the least significant position.
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*
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* Return: The extracted value.
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*/
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#define FIELD_GET(_mask, _value) \
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((typeof(_mask))(((_value) & (_mask)) >> __bf_shf(_mask)))
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#endif /* OPENOCD_HELPER_BITFIELD_H */
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