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author | Alejandro Colomar <alx.manpages@gmail.com> | 2021-11-19 21:50:29 +0100 |
---|---|---|
committer | Alejandro Colomar <alx.manpages@gmail.com> | 2021-11-20 13:22:21 +0100 |
commit | e2469fced9f3d786a42ce90082ffd977f5e613ee (patch) | |
tree | 95189cdb70706840700d1cde2947c40ec35a3c86 | |
parent | 44eae19045a2fc77b17c7bd047b652e3a72a6c7b (diff) |
linux/power_of_2.h: Add __IS_POWER_OF_2(n) and __IS_POWER_OF_2_OR_0(n) macros
Tested:
$ cat pow2.c
#include <stdio.h>
#define is_power_of_2_or_0(n) (((n) & ((n) - 1)) == 0)
#define is_power_of_2(n) (is_power_of_2_or_0(n) && ((n) != 0))
int main(void)
{
printf("%i, %i, %i\n", 8, is_power_of_2_or_0(8), is_power_of_2(8));
printf("%i, %i, %i\n", 7, is_power_of_2_or_0(7), is_power_of_2(7));
printf("%i, %i, %i\n", 6, is_power_of_2_or_0(6), is_power_of_2(6));
printf("%i, %i, %i\n", 5, is_power_of_2_or_0(5), is_power_of_2(5));
printf("%i, %i, %i\n", 4, is_power_of_2_or_0(4), is_power_of_2(4));
printf("%i, %i, %i\n", 3, is_power_of_2_or_0(3), is_power_of_2(3));
printf("%i, %i, %i\n", 2, is_power_of_2_or_0(2), is_power_of_2(2));
printf("%i, %i, %i\n", 1, is_power_of_2_or_0(1), is_power_of_2(1));
printf("%i, %i, %i\n", 0, is_power_of_2_or_0(0), is_power_of_2(0));
}
$ cc pow2.c
$ ./a.out
8, 1, 1
7, 0, 0
6, 0, 0
5, 0, 0
4, 1, 1
3, 0, 0
2, 1, 1
1, 1, 1
0, 1, 0
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
-rw-r--r-- | include/linux/power_of_2.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/power_of_2.h b/include/linux/power_of_2.h new file mode 100644 index 000000000000..812fe86eefcd --- /dev/null +++ b/include/linux/power_of_2.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_POWER_OF_2_H +#define _LINUX_POWER_OF_2_H + + +#define __IS_POWER_OF_2_OR_0(n) (((n) & ((n) - 1)) == 0) +#define __IS_POWER_OF_2(n) (__IS_POWER_OF_2_OR_0(n) && ((n) != 0)) + + +#endif /* _LINUX_POWER_OF_2_H */ |