| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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. 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 | } |