diff --git a/Makefile b/Makefile
index 60acaea..4d229a0 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,7 @@ CFLAGS += -Iinclude
 CFLAGS += -Wall -Wundef -Wextra -Wshadow -Wimplicit-function-declaration
 CFLAGS += -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes
 
+obj-y += source/bitops.o
 obj-y += source/bitset.o
 obj-y += source/main.o
 obj-y += source/shell/cmd.o
diff --git a/include/bitops.h b/include/bitops.h
new file mode 100644
index 0000000..abee5a9
--- /dev/null
+++ b/include/bitops.h
@@ -0,0 +1,3 @@
+#pragma once
+
+unsigned ilog2(unsigned n);
diff --git a/source/bitops.c b/source/bitops.c
new file mode 100644
index 0000000..59048e2
--- /dev/null
+++ b/source/bitops.c
@@ -0,0 +1,11 @@
+#include <bitops.h>
+
+unsigned ilog2(unsigned n)
+{
+	unsigned ret = 0;
+
+	while (n >>= 1)
+		++ret;
+
+	return ret;
+}