1 files changed, 19 insertions, 13 deletions

diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c
index fc2eeb7cb2ea..1ef4cc344977 100644
--- a/lib/int_sqrt.c
+++ b/lib/int_sqrt.c
@@ -1,3 +1,9 @@
+/*
+ * Copyright (C) 2013 Davidlohr Bueso <davidlohr.bueso@hp.com>
+ *
+ *  Based on the shift-and-subtract algorithm for computing integer
+ *  square root from Guy L. Steele.
+ */
 
 #include <linux/kernel.h>
 #include <linux/export.h>
@@ -10,23 +16,23 @@
  */
 unsigned long int_sqrt(unsigned long x)
 {
-        unsigned long op, res, one;
+        unsigned long b, m, y = 0;
 
-        op = x;
-        res = 0;
+        if (x <= 1)
+                return x;
 
-        one = 1UL << (BITS_PER_LONG - 2);
-        while (one > op)
-                one >>= 2;
+        m = 1UL << (BITS_PER_LONG - 2);
+        while (m != 0) {
+                b = y + m;
+                y >>= 1;
 
-        while (one != 0) {
-                if (op >= res + one) {
-                        op = op - (res + one);
-                        res = res +  2 * one;
+                if (x >= b) {
+                        x -= b;
+                        y += m;
                 }
-                res /= 2;
-                one /= 4;
+                m >>= 2;
         }
-        return res;
+
+        return y;
 }
 EXPORT_SYMBOL(int_sqrt);