| /* |
| * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test |
| * @library /test/lib |
| * @build jdk.test.lib.RandomFactory |
| * @run main MultiplicationTests |
| * @bug 5100935 |
| * @summary Tests for multiplication methods (use -Dseed=X to set PRNG seed) |
| * @key randomness |
| */ |
| |
| import java.math.BigInteger; |
| import jdk.test.lib.RandomFactory; |
| |
| public class MultiplicationTests { |
| private MultiplicationTests(){} |
| |
| // Number of random products to test. |
| private static final int COUNT = 1 << 16; |
| |
| // Initialize shared random number generator |
| private static java.util.Random rnd = RandomFactory.getRandom(); |
| |
| // Calculate high 64 bits of 128 product using BigInteger. |
| private static long multiplyHighBigInt(long x, long y) { |
| return BigInteger.valueOf(x).multiply(BigInteger.valueOf(y)) |
| .shiftRight(64).longValue(); |
| } |
| |
| // Check Math.multiplyHigh(x,y) against multiplyHighBigInt(x,y) |
| private static boolean check(long x, long y) { |
| long p1 = multiplyHighBigInt(x, y); |
| long p2 = Math.multiplyHigh(x, y); |
| if (p1 != p2) { |
| System.err.printf("Error - x:%d y:%d p1:%d p2:%d\n", x, y, p1, p2); |
| return false; |
| } else { |
| return true; |
| } |
| } |
| |
| private static int testMultiplyHigh() { |
| int failures = 0; |
| |
| // check some boundary cases |
| long[][] v = new long[][]{ |
| {0L, 0L}, |
| {-1L, 0L}, |
| {0L, -1L}, |
| {1L, 0L}, |
| {0L, 1L}, |
| {-1L, -1L}, |
| {-1L, 1L}, |
| {1L, -1L}, |
| {1L, 1L}, |
| {Long.MAX_VALUE, Long.MAX_VALUE}, |
| {Long.MAX_VALUE, -Long.MAX_VALUE}, |
| {-Long.MAX_VALUE, Long.MAX_VALUE}, |
| {Long.MAX_VALUE, Long.MIN_VALUE}, |
| {Long.MIN_VALUE, Long.MAX_VALUE}, |
| {Long.MIN_VALUE, Long.MIN_VALUE} |
| }; |
| |
| for (long[] xy : v) { |
| if(!check(xy[0], xy[1])) { |
| failures++; |
| } |
| } |
| |
| // check some random values |
| for (int i = 0; i < COUNT; i++) { |
| if (!check(rnd.nextLong(), rnd.nextLong())) { |
| failures++; |
| } |
| } |
| |
| return failures; |
| } |
| |
| public static void main(String argv[]) { |
| int failures = testMultiplyHigh(); |
| |
| if (failures > 0) { |
| System.err.println("Multiplication testing encountered " |
| + failures + " failures."); |
| throw new RuntimeException(); |
| } else { |
| System.out.println("MultiplicationTests succeeded"); |
| } |
| } |
| } |