1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 3 #ifndef __SRC_INCLUDE_BASE3_H__ 4 #define __SRC_INCLUDE_BASE3_H__ 5 6 /* We translate a floating pin (Z) as the ternary digit 2. */ 7 #define Z 2 8 9 /* 10 * This provides a variadic macro BASE3() that can be used to translate a set of 11 * pin states into its base-3 integer representation, even in the context of a 12 * static initializer. You can call it with any number of up to 6 arguments, 13 * e.g. BASE3(1, Z) -> 5 or BASE3(0, Z, 1, 0) -> 21. Just don't look too closely 14 * at how the sausage is made. (Pay extra attention to typos when expanding it!) 15 */ 16 #define _BASE3_IMPL_1(arg0, arg1, arg2, arg3, arg4, arg5) arg0 17 #define _BASE3_IMPL_2(arg0, arg1, arg2, arg3, arg4, arg5) \ 18 (arg1 + (3 * _BASE3_IMPL_1(arg0, arg1, arg2, arg3, arg4, arg5))) 19 #define _BASE3_IMPL_3(arg0, arg1, arg2, arg3, arg4, arg5) \ 20 (arg2 + (3 * _BASE3_IMPL_2(arg0, arg1, arg2, arg3, arg4, arg5))) 21 #define _BASE3_IMPL_4(arg0, arg1, arg2, arg3, arg4, arg5) \ 22 (arg3 + (3 * _BASE3_IMPL_3(arg0, arg1, arg2, arg3, arg4, arg5))) 23 #define _BASE3_IMPL_5(arg0, arg1, arg2, arg3, arg4, arg5) \ 24 (arg4 + (3 * _BASE3_IMPL_4(arg0, arg1, arg2, arg3, arg4, arg5))) 25 #define _BASE3_IMPL_6(arg0, arg1, arg2, arg3, arg4, arg5) \ 26 (arg5 + (3 * _BASE3_IMPL_5(arg0, arg1, arg2, arg3, arg4, arg5))) 27 #define _BASE3_IMPL(arg0, arg1, arg2, arg3, arg4, arg5, NARGS, ...) \ 28 _BASE3_IMPL##NARGS(arg0, arg1, arg2, arg3, arg4, arg5) 29 #define BASE3(...) _BASE3_IMPL(__VA_ARGS__, _6, _5, _4, _3, _2, _1) 30 31 #endif /* __SRC_INCLUDE_BASE3_H__ */ 32