1 /*
 2  * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
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22  */
23 package org.openjdk.bench.valhalla.ackermann;
24 
25 import org.openjdk.jmh.annotations.Benchmark;
26 import org.openjdk.jmh.annotations.OperationsPerInvocation;
27 
28 public class Identity extends AckermannBase {
29 
30     private static IdentityLong ack_identity(IdentityLong x, IdentityLong y) {
31         return x.value() == 0 ?
32                 IdentityLong.valueOf(y.value() + 1) :
33                 (y.value() == 0 ?
34                         ack_identity(IdentityLong.valueOf(x.value() - 1), IdentityLong.valueOf(1)) :
35                         ack_identity(IdentityLong.valueOf(x.value() - 1), ack_identity(x, IdentityLong.valueOf(y.value() - 1))));
36     }
37 
38     @Benchmark
39     @OperationsPerInvocation(OPI)
40     public long ackermann() {
41         return ack_identity(IdentityLong.valueOf(X1), IdentityLong.valueOf(Y1)).value()
42                 + ack_identity(IdentityLong.valueOf(X2), IdentityLong.valueOf(Y2)).value()
43                 + ack_identity(IdentityLong.valueOf(X3), IdentityLong.valueOf(Y3)).value();
44     }
45 
46     public static class IdentityLong {
47 
48         public final long v0;
49 
50         public IdentityLong(long v0) {
51             this.v0 = v0;
52         }
53 
54         public long value() {
55             return v0;
56         }
57 
58         public static IdentityLong valueOf(long value) {
59             return new IdentityLong(value);
60         }
61 
62     }
63 
64 }