/*

 * Copyright (c) 2016, 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

 * @bug 8148175

 * @run main/othervm/timeout=300 -Xbatch -Xmx128m PreserveFPRegistersTest

 */

public class PreserveFPRegistersTest {

    public static void main(String... args) throws InterruptedException {

        new PreserveFPRegistersTest().go();

    }

    public final Object[][] storage;

    /**

     * Number of objects per region.

     */

    public final int K = 10;

    /**

     * Length of object array: sizeOf(Object[N]) ~= regionSize / K .

     */

    public final int N;

    /**

     * How many regions involved into testing.

     */

    public final int regionCount;

    PreserveFPRegistersTest() {

        long regionSize = 1_000_000; //WB.g1RegionSize();

        Runtime rt = Runtime.getRuntime();

        long used = rt.totalMemory() - rt.freeMemory();

        long totalFree = rt.maxMemory() - used;

        regionCount = (int) ( (totalFree / regionSize) * 0.9);

        int refSize = 4;

        N = (int) ((regionSize / K ) / refSize) - 5;

        storage = new Object[regionCount * K][];

        for (int i = 0; i < storage.length; i++) {

            storage[i] = new Object[N];

        }

    }

    public void go() throws InterruptedException {

        final float FINAL = getValue();

        for (int to = 0; to < regionCount; to++) {

            Object celebrity = storage[to * K];

            for (int from = 0; from < regionCount; from++) {

                for (int rn = 0; rn != 100; rn++) {

                    storage[getY(to, from, rn)][getX(to, from, rn)] = celebrity;

                }

                if (FINAL != getValue()) {

                    throw new AssertionError("Final value has changed: " + FINAL + " != " + getValue());

                }

            }

        }

        System.out.println("TEST PASSED");

    }

    public float getValue() {

        return 6;

    }

    private int getX(int to, int from, int rn) {

        return (rn*regionCount + to) % N;

    }

    private int getY(int to, int from, int rn) {

        return ((rn*regionCount + to) / N + from * K) % (regionCount*K) ;

    }

}