bitops: add ilog2()

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

include/bitops.h

@@ -0,0 +1,3 @@
+#pragma once
+
+unsigned ilog2(unsigned n);

source/bitops.c

@@ -0,0 +1,11 @@
+#include <bitops.h>
+
+unsigned ilog2(unsigned n)
+{
+	unsigned ret = 0;
+
+	while (n >>= 1)
+		++ret;
+
+	return ret;
+}