diff options
| author |   Robert P. J. Day <rpjday@mindspring.com> | 2007-01-30 06:06:00 -0500 |
|---|---|---|
| committer |   Paul Mackerras <paulus@samba.org> | 2007-02-07 14:03:19 +1100 |
| commit | 63c2f782e8f6aafbc11b14b2cb291b3dc9fc217d (patch) | |
| tree | cbcd1f138a886529ec62a21c5dd4b2c87581058d /include/linux/log2.h | |
| parent | [POWERPC] MPIC: support more than 256 sources (diff) | |
| download | linux-dev-63c2f782e8f6aafbc11b14b2cb291b3dc9fc217d.tar.xz linux-dev-63c2f782e8f6aafbc11b14b2cb291b3dc9fc217d.zip | |
[POWERPC] Add "is_power_of_2" checking to log2.h.
Add the inline function "is_power_of_2()" to log2.h, where the value
zero is *not* considered to be a power of two.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'include/linux/log2.h')
| -rw-r--r-- | include/linux/log2.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/log2.h b/include/linux/log2.h index d02e1a547a7e..99922bedfcc9 100644 --- a/include/linux/log2.h +++ b/include/linux/log2.h @@ -44,6 +44,17 @@ int __ilog2_u64(u64 n) #endif /* + * Determine whether some value is a power of two, where zero is + * *not* considered a power of two. + */ + +static inline __attribute__((const)) +bool is_power_of_2(unsigned long n) +{ + return (n != 0 && ((n & (n - 1)) == 0)); +} + +/* * round up to nearest power of two */ static inline __attribute__((const)) |