Re: [PATCH] Add "is_power_of_2" checking to log2.h.

Robert P. J. Day wrote:

  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 <[email protected]>

 /*
+ *  Determine whether some value is a power of two, where zero is
+ * *not* considered a power of two.
+ */

Why the qualifier? Zero *is* not a power of 2, is it?

+
+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))

--
SUSE Labs, Novell Inc.

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