| From | Alejandro Colomar <> | Subject | [PATCH v2 18/20] linux/power_of_2.h: Add __IS_POWER_OF_2(n) and __IS_POWER_OF_2_OR_0(n) macros | Date | Sat, 20 Nov 2021 14:01:02 +0100 |
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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> --- include/linux/power_of_2.h | 10 ++++++++++ 1 file changed, 10 insertions(+) create mode 100644 include/linux/power_of_2.h
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 */ -- 2.33.1
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