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 26 package sun.misc; 27 28 /** 29 * This class contains additional constants documenting limits of the 30 * <code>double</code> type. 31 * 32 * @author Joseph D. Darcy 33 */ 34 35 public class DoubleConsts { 36 /** 37 * Don't let anyone instantiate this class. 38 */ DoubleConsts()39 private DoubleConsts() {} 40 41 public static final double POSITIVE_INFINITY = java.lang.Double.POSITIVE_INFINITY; 42 public static final double NEGATIVE_INFINITY = java.lang.Double.NEGATIVE_INFINITY; 43 public static final double NaN = java.lang.Double.NaN; 44 public static final double MAX_VALUE = java.lang.Double.MAX_VALUE; 45 public static final double MIN_VALUE = java.lang.Double.MIN_VALUE; 46 47 /** 48 * A constant holding the smallest positive normal value of type 49 * <code>double</code>, 2<sup>-1022</sup>. It is equal to the 50 * value returned by 51 * <code>Double.longBitsToDouble(0x0010000000000000L)</code>. 52 * 53 * @since 1.5 54 */ 55 public static final double MIN_NORMAL = 2.2250738585072014E-308; 56 57 58 /** 59 * The number of logical bits in the significand of a 60 * <code>double</code> number, including the implicit bit. 61 */ 62 public static final int SIGNIFICAND_WIDTH = 53; 63 64 /** 65 * Maximum exponent a finite <code>double</code> number may have. 66 * It is equal to the value returned by 67 * <code>Math.ilogb(Double.MAX_VALUE)</code>. 68 */ 69 public static final int MAX_EXPONENT = 1023; 70 71 /** 72 * Minimum exponent a normalized <code>double</code> number may 73 * have. It is equal to the value returned by 74 * <code>Math.ilogb(Double.MIN_NORMAL)</code>. 75 */ 76 public static final int MIN_EXPONENT = -1022; 77 78 /** 79 * The exponent the smallest positive <code>double</code> 80 * subnormal value would have if it could be normalized. It is 81 * equal to the value returned by 82 * <code>FpUtils.ilogb(Double.MIN_VALUE)</code>. 83 */ 84 public static final int MIN_SUB_EXPONENT = MIN_EXPONENT - 85 (SIGNIFICAND_WIDTH - 1); 86 87 /** 88 * Bias used in representing a <code>double</code> exponent. 89 */ 90 public static final int EXP_BIAS = 1023; 91 92 /** 93 * Bit mask to isolate the sign bit of a <code>double</code>. 94 */ 95 public static final long SIGN_BIT_MASK = 0x8000000000000000L; 96 97 /** 98 * Bit mask to isolate the exponent field of a 99 * <code>double</code>. 100 */ 101 public static final long EXP_BIT_MASK = 0x7FF0000000000000L; 102 103 /** 104 * Bit mask to isolate the significand field of a 105 * <code>double</code>. 106 */ 107 public static final long SIGNIF_BIT_MASK = 0x000FFFFFFFFFFFFFL; 108 109 static { 110 // verify bit masks cover all bit positions and that the bit 111 // masks are non-overlapping 112 assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0L) && 113 (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0L) && 114 ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0L) && 115 ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0L))); 116 } 117 } 118