summaryrefslogtreecommitdiffstats
path: root/lib/int_sqrt.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/int_sqrt.c')
-rw-r--r--lib/int_sqrt.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c
new file mode 100644
index 000000000000..a5d2cdc5684c
--- /dev/null
+++ b/lib/int_sqrt.c
@@ -0,0 +1,32 @@
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+/**
+ * int_sqrt - rough approximation to sqrt
+ * @x: integer of which to calculate the sqrt
+ *
+ * A very rough approximation to the sqrt() function.
+ */
+unsigned long int_sqrt(unsigned long x)
+{
+ unsigned long op, res, one;
+
+ op = x;
+ res = 0;
+
+ one = 1 << 30;
+ while (one > op)
+ one >>= 2;
+
+ while (one != 0) {
+ if (op >= res + one) {
+ op = op - (res + one);
+ res = res + 2 * one;
+ }
+ res /= 2;
+ one /= 4;
+ }
+ return res;
+}
+EXPORT_SYMBOL(int_sqrt);