/******************************************************************************
* Copyright (c) 2009 - 2015 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*****************************************************************************/
package data.causality;
/**
* Causality test case 14 from
* http://www.cs.umd.edu/~pugh/java/memoryModel/CausalityTestCases.html
*
* <pre>
* Initially, a = b = y = 0, y is volatile
*
* Thread 1:
* r1 = a
* if (r1 == 0)
* y = 1
* else
* b = 1
*
* Thread 2:
* do {
* r2 = y
* r3 = b
* } while (r2 + r3 == 0);
* a = 1;
*
* Behavior in question: r1 == r3 = 1; r2 = 0
*
* Decision: Disallowed In all sequentially consistent executions, r1 = 0 and
* the program is correctly synchronized. Since the program is correctly
* synchronized in all SC executions, no non-sc behaviors are allowed.
* </pre>
*
*
* @author etorlak
*/
public final class Test14 {
static int a = 0, b = 0;
static volatile int y = 0;
public static final void thread1() {
final int r1 = a;
if (r1 == 0)
y = 1;
else
b = 1;
assert r1==1;
}
public static final void thread2() {
int r2, r3;
do {
r2 = y;
r3 = b;
} while (r2 + r3 == 0);
a = 1;
assert r2==0;
assert r3==1;
}
}