test/micro/org/openjdk/bench/java/math/BigIntegers.java

*** 43,60 ****
  @BenchmarkMode(Mode.AverageTime)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  @State(Scope.Thread)
  public class BigIntegers {
  
!     private BigInteger[] hugeArray, largeArray, smallArray;
      public String[] dummyStringArray;
      public Object[] dummyArr;
      private static final int TESTSIZE = 1000;
  
      @Setup
      public void setup() {
          Random r = new Random(1123);
  
          hugeArray = new BigInteger[TESTSIZE]; /*
           * Huge numbers larger than
           * MAX_LONG
           */
--- 43,61 ----
  @BenchmarkMode(Mode.AverageTime)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  @State(Scope.Thread)
  public class BigIntegers {
  
!     private BigInteger[] hugeArray, largeArray, smallArray, shiftArray;
      public String[] dummyStringArray;
      public Object[] dummyArr;
      private static final int TESTSIZE = 1000;
  
      @Setup
      public void setup() {
          Random r = new Random(1123);
+         int numbits = r.nextInt(16384);
  
          hugeArray = new BigInteger[TESTSIZE]; /*
           * Huge numbers larger than
           * MAX_LONG
           */
*** 65,74 ****
--- 66,79 ----
           */
          smallArray = new BigInteger[TESTSIZE]; /*
           * Small number less than
           * MAX_INT
           */
+         shiftArray = new BigInteger[TESTSIZE]; /*
+          * Each array entry is atmost 16k bits
+          * in size
+          */
  
          dummyStringArray = new String[TESTSIZE];
          dummyArr = new Object[TESTSIZE];
  
          for (int i = 0; i < TESTSIZE; i++) {
*** 76,85 ****
--- 81,91 ----
  
              hugeArray[i] = new BigInteger("" + ((long) value + (long) Integer.MAX_VALUE)
                      + ((long) value + (long) Integer.MAX_VALUE));
              largeArray[i] = new BigInteger("" + ((long) value + (long) Integer.MAX_VALUE));
              smallArray[i] = new BigInteger("" + ((long) value / 1000));
+             shiftArray[i] = new BigInteger(numbits, r);
          }
      }
  
      /** Test BigInteger.toString() with huge numbers larger than MAX_LONG */
      @Benchmark
*** 135,140 ****
--- 141,180 ----
              }
              tmp = tmp.add(s);
          }
          bh.consume(tmp);
      }
+ 
+     /** Invokes the shiftLeft method of BigInteger with different values. */
+     @Benchmark
+     @OperationsPerInvocation(TESTSIZE)
+     public void testLeftShift(Blackhole bh) {
+         Random rand = new Random();
+         int shift = rand.nextInt(30) + 1;
+         BigInteger tmp = null;
+         for (BigInteger s : shiftArray) {
+             if (tmp == null) {
+                 tmp = s;
+                 continue;
+             }
+             tmp = tmp.shiftLeft(shift);
+         }
+         bh.consume(tmp);
+     }
+ 
+     /** Invokes the shiftRight method of BigInteger with different values. */
+     @Benchmark
+     @OperationsPerInvocation(TESTSIZE)
+     public void testRightShift(Blackhole bh) {
+         Random rand = new Random();
+         int shift = rand.nextInt(30) + 1;
+         BigInteger tmp = null;
+         for (BigInteger s : shiftArray) {
+             if (tmp == null) {
+                 tmp = s;
+                 continue;
+             }
+             tmp = tmp.shiftRight(shift);
+         }
+         bh.consume(tmp);
+     }
  }