1 /*

     2  * Copyright (c) 2003, 2014, 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.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.misc;

    27 

    28 /**

    29  * This class contains additional constants documenting limits of the

    30  * <code>float</code> type.

    31  *

    32  * @author Joseph D. Darcy

    33  */

    34 

    35 public class FloatConsts {

    36     /**

    37      * Don't let anyone instantiate this class.

    38      */

    39     private FloatConsts() {}

    40 

    41     public static final float POSITIVE_INFINITY = java.lang.Float.POSITIVE_INFINITY;

    42     public static final float NEGATIVE_INFINITY = java.lang.Float.NEGATIVE_INFINITY;

    43     public static final float NaN = java.lang.Float.NaN;

    44     public static final float MAX_VALUE = java.lang.Float.MAX_VALUE;

    45     public static final float MIN_VALUE = java.lang.Float.MIN_VALUE;

    46 

    47     /**

    48      * A constant holding the smallest positive normal value of type

    49      * <code>float</code>, 2<sup>-126</sup>.  It is equal to the value

    50      * returned by <code>Float.intBitsToFloat(0x00800000)</code>.

    51      */

    52     public static final float   MIN_NORMAL      = 1.17549435E-38f;

    53 

    54     /**

    55      * The number of logical bits in the significand of a

    56      * <code>float</code> number, including the implicit bit.

    57      */

    58     public static final int SIGNIFICAND_WIDTH   = 24;

    59 

    60     /**

    61      * Maximum exponent a finite <code>float</code> number may have.

    62      * It is equal to the value returned by

    63      * <code>Math.ilogb(Float.MAX_VALUE)</code>.

    64      */

    65     public static final int     MAX_EXPONENT    = 127;

    66 

    67     /**

    68      * Minimum exponent a normalized <code>float</code> number may

    69      * have.  It is equal to the value returned by

    70      * <code>Math.ilogb(Float.MIN_NORMAL)</code>.

    71      */

    72     public static final int     MIN_EXPONENT    = -126;

    73 

    74     /**

    75      * The exponent the smallest positive <code>float</code> subnormal

    76      * value would have if it could be normalized.

    77      */

    78     public static final int     MIN_SUB_EXPONENT = MIN_EXPONENT -

    79                                                    (SIGNIFICAND_WIDTH - 1);

    80 

    81     /**

    82      * Bias used in representing a <code>float</code> exponent.

    83      */

    84     public static final int     EXP_BIAS        = 127;

    85 

    86     /**

    87      * Bit mask to isolate the sign bit of a <code>float</code>.

    88      */

    89     public static final int     SIGN_BIT_MASK   = 0x80000000;

    90 

    91     /**

    92      * Bit mask to isolate the exponent field of a

    93      * <code>float</code>.

    94      */

    95     public static final int     EXP_BIT_MASK    = 0x7F800000;

    96 

    97     /**

    98      * Bit mask to isolate the significand field of a

    99      * <code>float</code>.

   100      */

   101     public static final int     SIGNIF_BIT_MASK = 0x007FFFFF;

   102 

   103     static {

   104         // verify bit masks cover all bit positions and that the bit

   105         // masks are non-overlapping

   106         assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0) &&

   107                (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0) &&

   108                 ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0) &&

   109                 ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0)));

   110     }

   111 }