| Julius Werner | 886d29b | 2014-09-24 15:40:49 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This file is part of the coreboot project. |
| 3 | * |
| 4 | * Copyright 2014 Google Inc. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; version 2 of the License. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | |
| 20 | #ifndef __SRC_INCLUDE_BASE3_H__ |
| 21 | #define __SRC_INCLUDE_BASE3_H__ |
| 22 | |
| 23 | /* We translate a floating pin (Z) as the ternary digit 2. */ |
| 24 | #define Z 2 |
| 25 | |
| 26 | /* |
| 27 | * This provides a variadic macro BASE3() that can be used to translate a set of |
| 28 | * pin states into its base-3 integer representation, even in the context of a |
| 29 | * static initializer. You can call it with any number of up to 6 arguments, |
| 30 | * e.g. BASE3(1, Z) -> 5 or BASE3(0, Z, 1, 0) -> 21. Just don't look too closely |
| 31 | * at how the sausage is made. (Pay extra attention to typos when expanding it!) |
| 32 | */ |
| 33 | #define _BASE3_IMPL_1(arg0, arg1, arg2, arg3, arg4, arg5) arg0 |
| 34 | #define _BASE3_IMPL_2(arg0, arg1, arg2, arg3, arg4, arg5) \ |
| 35 | (arg1 + (3 * _BASE3_IMPL_1(arg0, arg1, arg2, arg3, arg4, arg5))) |
| 36 | #define _BASE3_IMPL_3(arg0, arg1, arg2, arg3, arg4, arg5) \ |
| 37 | (arg2 + (3 * _BASE3_IMPL_2(arg0, arg1, arg2, arg3, arg4, arg5))) |
| 38 | #define _BASE3_IMPL_4(arg0, arg1, arg2, arg3, arg4, arg5) \ |
| 39 | (arg3 + (3 * _BASE3_IMPL_3(arg0, arg1, arg2, arg3, arg4, arg5))) |
| 40 | #define _BASE3_IMPL_5(arg0, arg1, arg2, arg3, arg4, arg5) \ |
| 41 | (arg4 + (3 * _BASE3_IMPL_4(arg0, arg1, arg2, arg3, arg4, arg5))) |
| 42 | #define _BASE3_IMPL_6(arg0, arg1, arg2, arg3, arg4, arg5) \ |
| 43 | (arg5 + (3 * _BASE3_IMPL_5(arg0, arg1, arg2, arg3, arg4, arg5))) |
| 44 | #define _BASE3_IMPL(arg0, arg1, arg2, arg3, arg4, arg5, NARGS, ...) \ |
| 45 | _BASE3_IMPL##NARGS(arg0, arg1, arg2, arg3, arg4, arg5) |
| 46 | #define BASE3(...) _BASE3_IMPL(__VA_ARGS__, _6, _5, _4, _3, _2, _1) |
| 47 | |
| 48 | #endif /* __SRC_INCLUDE_BASE3_H__ */ |