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/*
* Copyright (c) 2016, 2021, 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 8188044
* @summary Tests for multiplication methods (use -Dseed=X to set PRNG seed)
* @key randomness
*/
import java.math.BigInteger;
import java.util.function.BiFunction;
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();
}
// Calculate high 64 bits of unsigned 128 product using signed multiply
private static long unsignedMultiplyHigh(long x, long y) {
long x0 = x & 0xffffffffL;
long x1 = x >>> 32;
long y0 = y & 0xffffffffL;
long y1 = y >>> 32;
long t = x1 * y0 + ((x0 * y0) >>> 32);
long z0 = x0 * y1 + (t & 0xffffffffL);
long z1 = t >>> 32;
return x1 * y1 + z1 + (z0 >>> 32);
}
// Compare results of two functions for a pair of values
private static boolean check(BiFunction<Long,Long,Long> reference,
BiFunction<Long,Long,Long> multiply, long x, long y) {
long p1 = reference.apply(x, y);
long p2 = multiply.apply(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;
}
}
// Check Math.multiplyHigh(x,y) against multiplyHighBigInt(x,y)
private static boolean checkSigned(long x, long y) {
return check((a,b) -> multiplyHighBigInt(a,b),
(a,b) -> Math.multiplyHigh(a, b), x, y);
}
// Check Math.unsignedMultiplyHigh(x,y) against unsignedMultiplyHigh(x,y)
private static boolean checkUnsigned(long x, long y) {
return check((a,b) -> unsignedMultiplyHigh(a,b),
(a,b) -> Math.unsignedMultiplyHigh(a, b), x, y);
}
private static int test(BiFunction<Long,Long,Boolean> chk) {
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(!chk.apply(xy[0], xy[1])) {
failures++;
}
}
// check some random values
for (int i = 0; i < COUNT; i++) {
if (!chk.apply(rnd.nextLong(), rnd.nextLong())) {
failures++;
}
}
return failures;
}
private static int testMultiplyHigh() {
return test((x,y) -> checkSigned(x,y));
}
private static int testUnsignedMultiplyHigh() {
return test((x,y) -> checkUnsigned(x,y));
}
public static void main(String argv[]) {
int failures = testMultiplyHigh() + testUnsignedMultiplyHigh();
if (failures > 0) {
System.err.println("Multiplication testing encountered "
+ failures + " failures.");
throw new RuntimeException();
} else {
System.out.println("MultiplicationTests succeeded");
}
}
}
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