| Angel Pons | 32859fc | 2020-04-02 23:48:27 +0200 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
| Julius Werner | 886d29b | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 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__ */ |