1 /* SPDX-License-Identifier: MIT */ 2 /* Copyright © 2026 Intel Corporation */ 3 4 #ifndef _PICK_H_ 5 #define _PICK_H_ 6 7 /* 8 * Given the first two numbers __a and __b of arbitrarily many evenly spaced 9 * numbers, pick the 0-based __index'th value. 10 * 11 * Always prefer this over _PICK() if the numbers are evenly spaced. 12 */ 13 #define _PICK_EVEN(__index, __a, __b) ((__a) + (__index) * ((__b) - (__a))) 14 15 /* 16 * Like _PICK_EVEN(), but supports 2 ranges of evenly spaced address offsets. 17 * @__c_index corresponds to the index in which the second range starts to be 18 * used. Using math interval notation, the first range is used for indexes [ 0, 19 * @__c_index), while the second range is used for [ @__c_index, ... ). Example: 20 * 21 * #define _FOO_A 0xf000 22 * #define _FOO_B 0xf004 23 * #define _FOO_C 0xf008 24 * #define _SUPER_FOO_A 0xa000 25 * #define _SUPER_FOO_B 0xa100 26 * #define FOO(x) _MMIO(_PICK_EVEN_2RANGES(x, 3, \ 27 * _FOO_A, _FOO_B, \ 28 * _SUPER_FOO_A, _SUPER_FOO_B)) 29 * 30 * This expands to: 31 * 0: 0xf000, 32 * 1: 0xf004, 33 * 2: 0xf008, 34 * 3: 0xa000, 35 * 4: 0xa100, 36 * 5: 0xa200, 37 * ... 38 */ 39 #define _PICK_EVEN_2RANGES(__index, __c_index, __a, __b, __c, __d) \ 40 (BUILD_BUG_ON_ZERO(!__is_constexpr(__c_index)) + \ 41 ((__index) < (__c_index) ? _PICK_EVEN(__index, __a, __b) : \ 42 _PICK_EVEN((__index) - (__c_index), __c, __d))) 43 44 /* 45 * Given the arbitrary numbers in varargs, pick the 0-based __index'th number. 46 * 47 * Always prefer _PICK_EVEN() over this if the numbers are evenly spaced. 48 */ 49 #define _PICK(__index, ...) (((const u32 []){ __VA_ARGS__ })[__index]) 50 51 #endif 52