1/*
2 * Copyright (c) 2003, 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
26package 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
35public 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.  It is equal to the
77     * value returned by <code>FpUtils.ilogb(Float.MIN_VALUE)</code>.
78     */
79    public static final int     MIN_SUB_EXPONENT = MIN_EXPONENT -
80                                                   (SIGNIFICAND_WIDTH - 1);
81
82    /**
83     * Bias used in representing a <code>float</code> exponent.
84     */
85    public static final int     EXP_BIAS        = 127;
86
87    /**
88     * Bit mask to isolate the sign bit of a <code>float</code>.
89     */
90    public static final int     SIGN_BIT_MASK   = 0x80000000;
91
92    /**
93     * Bit mask to isolate the exponent field of a
94     * <code>float</code>.
95     */
96    public static final int     EXP_BIT_MASK    = 0x7F800000;
97
98    /**
99     * Bit mask to isolate the significand field of a
100     * <code>float</code>.
101     */
102    public static final int     SIGNIF_BIT_MASK = 0x007FFFFF;
103
104    static {
105        // verify bit masks cover all bit positions and that the bit
106        // masks are non-overlapping
107        assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0) &&
108               (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0) &&
109                ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0) &&
110                ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0)));
111    }
112}
113