summary refs log tree commit diff
path: root/lib/int_sqrt.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/int_sqrt.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
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);