mirror of https://github.com/torvalds/linux.git
52 lines
1.6 KiB
C
52 lines
1.6 KiB
C
/* SPDX-License-Identifier: MIT */
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/* Copyright © 2026 Intel Corporation */
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#ifndef _PICK_H_
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#define _PICK_H_
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/*
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* Given the first two numbers __a and __b of arbitrarily many evenly spaced
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* numbers, pick the 0-based __index'th value.
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*
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* Always prefer this over _PICK() if the numbers are evenly spaced.
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*/
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#define _PICK_EVEN(__index, __a, __b) ((__a) + (__index) * ((__b) - (__a)))
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/*
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* Like _PICK_EVEN(), but supports 2 ranges of evenly spaced address offsets.
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* @__c_index corresponds to the index in which the second range starts to be
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* used. Using math interval notation, the first range is used for indexes [ 0,
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* @__c_index), while the second range is used for [ @__c_index, ... ). Example:
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*
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* #define _FOO_A 0xf000
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* #define _FOO_B 0xf004
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* #define _FOO_C 0xf008
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* #define _SUPER_FOO_A 0xa000
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* #define _SUPER_FOO_B 0xa100
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* #define FOO(x) _MMIO(_PICK_EVEN_2RANGES(x, 3, \
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* _FOO_A, _FOO_B, \
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* _SUPER_FOO_A, _SUPER_FOO_B))
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*
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* This expands to:
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* 0: 0xf000,
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* 1: 0xf004,
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* 2: 0xf008,
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* 3: 0xa000,
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* 4: 0xa100,
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* 5: 0xa200,
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* ...
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*/
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#define _PICK_EVEN_2RANGES(__index, __c_index, __a, __b, __c, __d) \
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(BUILD_BUG_ON_ZERO(!__is_constexpr(__c_index)) + \
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((__index) < (__c_index) ? _PICK_EVEN(__index, __a, __b) : \
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_PICK_EVEN((__index) - (__c_index), __c, __d)))
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/*
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* Given the arbitrary numbers in varargs, pick the 0-based __index'th number.
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*
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* Always prefer _PICK_EVEN() over this if the numbers are evenly spaced.
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*/
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#define _PICK(__index, ...) (((const u32 []){ __VA_ARGS__ })[__index])
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#endif
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