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-rw-r--r--tools/include/linux/log2.h26
1 files changed, 26 insertions, 0 deletions
diff --git a/tools/include/linux/log2.h b/tools/include/linux/log2.h
new file mode 100644
index 00000000000..141b7665d84
--- /dev/null
+++ b/tools/include/linux/log2.h
@@ -0,0 +1,26 @@
+/* Integer base 2 logarithm calculation
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _TOOLS_LINUX_LOG2_H
+#define _TOOLS_LINUX_LOG2_H
+
+/*
+ * 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));
+}
+
+#endif /* _TOOLS_LINUX_LOG2_H */