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Diffstat (limited to 'src/include/base3.h')
-rw-r--r-- | src/include/base3.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/include/base3.h b/src/include/base3.h new file mode 100644 index 0000000000..e92cc8bae7 --- /dev/null +++ b/src/include/base3.h @@ -0,0 +1,48 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2014 Google Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef __SRC_INCLUDE_BASE3_H__ +#define __SRC_INCLUDE_BASE3_H__ + +/* We translate a floating pin (Z) as the ternary digit 2. */ +#define Z 2 + +/* + * This provides a variadic macro BASE3() that can be used to translate a set of + * pin states into its base-3 integer representation, even in the context of a + * static initializer. You can call it with any number of up to 6 arguments, + * e.g. BASE3(1, Z) -> 5 or BASE3(0, Z, 1, 0) -> 21. Just don't look too closely + * at how the sausage is made. (Pay extra attention to typos when expanding it!) + */ +#define _BASE3_IMPL_1(arg0, arg1, arg2, arg3, arg4, arg5) arg0 +#define _BASE3_IMPL_2(arg0, arg1, arg2, arg3, arg4, arg5) \ + (arg1 + (3 * _BASE3_IMPL_1(arg0, arg1, arg2, arg3, arg4, arg5))) +#define _BASE3_IMPL_3(arg0, arg1, arg2, arg3, arg4, arg5) \ + (arg2 + (3 * _BASE3_IMPL_2(arg0, arg1, arg2, arg3, arg4, arg5))) +#define _BASE3_IMPL_4(arg0, arg1, arg2, arg3, arg4, arg5) \ + (arg3 + (3 * _BASE3_IMPL_3(arg0, arg1, arg2, arg3, arg4, arg5))) +#define _BASE3_IMPL_5(arg0, arg1, arg2, arg3, arg4, arg5) \ + (arg4 + (3 * _BASE3_IMPL_4(arg0, arg1, arg2, arg3, arg4, arg5))) +#define _BASE3_IMPL_6(arg0, arg1, arg2, arg3, arg4, arg5) \ + (arg5 + (3 * _BASE3_IMPL_5(arg0, arg1, arg2, arg3, arg4, arg5))) +#define _BASE3_IMPL(arg0, arg1, arg2, arg3, arg4, arg5, NARGS, ...) \ + _BASE3_IMPL##NARGS(arg0, arg1, arg2, arg3, arg4, arg5) +#define BASE3(...) _BASE3_IMPL(__VA_ARGS__, _6, _5, _4, _3, _2, _1) + +#endif /* __SRC_INCLUDE_BASE3_H__ */ |