1 /*
   2  * Copyright (c) 2005, 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
  21  * questions.
  22  */
  23 
  24 /*
  25  * @test
  26  * @bug 5037596
  27  * @summary Verify bitwise conversion works for non-canonical NaN values
  28  * @author Joseph D. Darcy
  29  */
  30 
  31 import static java.lang.Float.*;
  32 import static sun.misc.FloatConsts.*;
  33 
  34 public class BitwiseConversion {
  35     static int testNanCase(int x) {
  36         int errors  = 0;
  37         // Strip out sign and exponent bits
  38         int y = x & SIGNIF_BIT_MASK;
  39 
  40         float values[] = {
  41             intBitsToFloat(EXP_BIT_MASK | y),
  42             intBitsToFloat(SIGN_BIT_MASK | EXP_BIT_MASK | y)
  43         };
  44 
  45         for(float value: values) {
  46             if (!isNaN(value)) {
  47                 throw new RuntimeException("Invalid input " + y +
  48                                            "yielded non-NaN" + value);
  49             }
  50             int converted = floatToIntBits(value);
  51             if (converted != 0x7fc00000) {
  52                 errors++;
  53                 System.err.format("Non-canoncial NaN bits returned: %x%n",
  54                                   converted);
  55             }
  56         }
  57         return errors;
  58     }
  59 
  60     public static void main(String... argv) {
  61         int errors = 0;
  62 
  63         for (int i = 0; i < SIGNIFICAND_WIDTH-1; i++) {
  64             errors += testNanCase(1<<i);
  65         }
  66 
  67         if (floatToIntBits(Float.POSITIVE_INFINITY)
  68                 != 0x7F800000) {
  69             errors++;
  70             System.err.println("Bad conversion for +infinity.");
  71         }
  72 
  73         if (floatToIntBits(Float.NEGATIVE_INFINITY)
  74                 != 0xFF800000) {
  75             errors++;
  76             System.err.println("Bad conversion for -infinity.");
  77         }
  78 
  79         if (errors > 0)
  80             throw new RuntimeException();
  81     }
  82 }