1 /*
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3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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  *
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17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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23 
24 /*
25  * @test
26  * @library /test/lib
27  * @build jdk.test.lib.RandomFactory
28  * @run main MultiplicationTests
29  * @bug 5100935 8188044
30  * @summary Tests for multiplication methods (use -Dseed=X to set PRNG seed)
31  * @key randomness
32  */
33 
34 package test.java.lang.Math;
35 
36 import java.math.BigInteger;
37 import java.util.function.BiFunction;
38 import jdk.test.lib.RandomFactory;
39 
40 public class MultiplicationTests {
41     // Android-changed: Needs a public constructor in order to initialize the test on Android.
42     // private MultiplicationTests(){}
43 
44     // Number of random products to test.
45     private static final int COUNT = 1 << 16;
46 
47     // Initialize shared random number generator
48     private static java.util.Random rnd = RandomFactory.getRandom();
49 
50     // Calculate high 64 bits of 128 product using BigInteger.
multiplyHighBigInt(long x, long y)51     private static long multiplyHighBigInt(long x, long y) {
52         return BigInteger.valueOf(x).multiply(BigInteger.valueOf(y))
53             .shiftRight(64).longValue();
54     }
55 
56     // Calculate high 64 bits of unsigned 128 product using signed multiply
unsignedMultiplyHigh(long x, long y)57     private static long unsignedMultiplyHigh(long x, long y) {
58         long x0 = x & 0xffffffffL;
59         long x1 = x >>> 32;
60         long y0 = y & 0xffffffffL;
61         long y1 = y >>> 32;
62 
63         long t = x1 * y0 + ((x0 * y0) >>> 32);
64         long z0 = x0 * y1 + (t & 0xffffffffL);
65         long z1 = t >>> 32;
66 
67         return x1 * y1 + z1 + (z0 >>> 32);
68     }
69 
70     // Compare results of two functions for a pair of values
check(BiFunction<Long,Long,Long> reference, BiFunction<Long,Long,Long> multiply, long x, long y)71     private static boolean check(BiFunction<Long,Long,Long> reference,
72         BiFunction<Long,Long,Long> multiply, long x, long y) {
73         long p1 = reference.apply(x, y);
74         long p2 = multiply.apply(x, y);
75         if (p1 != p2) {
76             System.err.printf("Error - x:%d y:%d p1:%d p2:%d\n", x, y, p1, p2);
77             return false;
78         } else {
79             return true;
80         }
81     }
82 
83     // Check Math.multiplyHigh(x,y) against multiplyHighBigInt(x,y)
checkSigned(long x, long y)84     private static boolean checkSigned(long x, long y) {
85         return check((a,b) -> multiplyHighBigInt(a,b),
86             (a,b) -> Math.multiplyHigh(a, b), x, y);
87     }
88 
89     // Check Math.unsignedMultiplyHigh(x,y) against unsignedMultiplyHigh(x,y)
checkUnsigned(long x, long y)90     private static boolean checkUnsigned(long x, long y) {
91         return check((a,b) -> unsignedMultiplyHigh(a,b),
92             (a,b) -> Math.unsignedMultiplyHigh(a, b), x, y);
93     }
94 
95     // Android-added: Test functionally-equivalent StrictMath version.
96     // Check StrictMath.unsignedMultiplyHigh(x,y) against unsignedMultiplyHigh(x,y)
checkStrictMathUnsigned(long x, long y)97     private static boolean checkStrictMathUnsigned(long x, long y) {
98         return check((a,b) -> unsignedMultiplyHigh(a,b),
99                 (a,b) -> StrictMath.unsignedMultiplyHigh(a, b), x, y);
100     }
101 
test(BiFunction<Long,Long,Boolean> chk)102     private static int test(BiFunction<Long,Long,Boolean> chk) {
103         int failures = 0;
104 
105         // check some boundary cases
106         long[][] v = new long[][]{
107             {0L, 0L},
108             {-1L, 0L},
109             {0L, -1L},
110             {1L, 0L},
111             {0L, 1L},
112             {-1L, -1L},
113             {-1L, 1L},
114             {1L, -1L},
115             {1L, 1L},
116             {Long.MAX_VALUE, Long.MAX_VALUE},
117             {Long.MAX_VALUE, -Long.MAX_VALUE},
118             {-Long.MAX_VALUE, Long.MAX_VALUE},
119             {Long.MAX_VALUE, Long.MIN_VALUE},
120             {Long.MIN_VALUE, Long.MAX_VALUE},
121             {Long.MIN_VALUE, Long.MIN_VALUE}
122         };
123 
124         for (long[] xy : v) {
125             if(!chk.apply(xy[0], xy[1])) {
126                 failures++;
127             }
128         }
129 
130         // check some random values
131         for (int i = 0; i < COUNT; i++) {
132             if (!chk.apply(rnd.nextLong(), rnd.nextLong())) {
133                 failures++;
134             }
135         }
136 
137         return failures;
138     }
139 
testMultiplyHigh()140     private static int testMultiplyHigh() {
141         return test((x,y) -> checkSigned(x,y));
142     }
143 
testUnsignedMultiplyHigh()144     private static int testUnsignedMultiplyHigh() {
145         return test((x,y) -> checkUnsigned(x,y)
146                 // Android-added: Test functionally-equivalent StrictMath version.
147                 && checkStrictMathUnsigned(x,y));
148     }
149 
main(String argv[])150     public static void main(String argv[]) {
151         int failures = testMultiplyHigh() + testUnsignedMultiplyHigh();
152 
153         if (failures > 0) {
154             System.err.println("Multiplication testing encountered "
155                                + failures + " failures.");
156             throw new RuntimeException();
157         } else {
158             System.out.println("MultiplicationTests succeeded");
159         }
160     }
161 }
162