--- a/jdk/src/java.base/share/classes/java/lang/Math.java	Fri May 20 21:44:03 2016 +0100
+++ b/jdk/src/java.base/share/classes/java/lang/Math.java	Fri May 20 14:41:41 2016 -0700
@@ -1060,6 +1060,53 @@
     }
 
     /**
+     * Returns the exact mathematical product of the arguments.
+     *
+     * @param x the first value
+     * @param y the second value
+     * @return the result
+     */
+    public static long multiplyFull(int x, int y) {
+        return (long)x * (long)y;
+    }
+
+    /**
+     * Returns as a {@code long} the most significant 64 bits of the 128-bit
+     * product of two 64-bit factors.
+     *
+     * @param x the first value
+     * @param y the second value
+     * @return the result
+     */
+    public static long multiplyHigh(long x, long y) {
+        if (x < 0 || y < 0) {
+            // Use technique from section 8-2 of Henry S. Warren, Jr.,
+            // Hacker's Delight (2nd ed.) (Addison Wesley, 2013), 173-174.
+            long x1 = x >> 32;
+            long x2 = x & 0xFFFFFFFFL;
+            long y1 = y >> 32;
+            long y2 = y & 0xFFFFFFFFL;
+            long z2 = x2 * y2;
+            long t = x1 * y2 + (z2 >>> 32);
+            long z1 = t & 0xFFFFFFFFL;
+            long z0 = t >> 32;
+            z1 += x2 * y1;
+            return x1 * y1 + z0 + (z1 >> 32);
+        } else {
+            // Use Karatsuba technique with two base 2^32 digits.
+            long x1 = x >>> 32;
+            long y1 = y >>> 32;
+            long x2 = x & 0xFFFFFFFFL;
+            long y2 = y & 0xFFFFFFFFL;
+            long A = x1 * y1;
+            long B = x2 * y2;
+            long C = (x1 + x2) * (y1 + y2);
+            long K = C - A - B;
+            return (((B >>> 32) + K) >>> 32) + A;
+        }
+    }
+
+    /**
      * Returns the largest (closest to positive infinity)
      * {@code int} value that is less than or equal to the algebraic quotient.
      * There is one special case, if the dividend is the