1 /* 2 * Copyright (c) 2003, 2016, 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 jdk.internal.math; 27 28 /** 29 * This class contains additional constants documenting limits of the 30 * {@code double} type. 31 * 32 * @author Joseph D. Darcy 33 */ 34 35 public class DoubleConsts { 36 /** 37 * Don't let anyone instantiate this class. 38 */ 39 private DoubleConsts() {} 40 41 /** 42 * The number of logical bits in the significand of a 43 * {@code double} number, including the implicit bit. 44 */ 45 public static final int SIGNIFICAND_WIDTH = 53; 46 47 /** 48 * The exponent the smallest positive {@code double} 49 * subnormal value would have if it could be normalized.. 50 */ 51 public static final int MIN_SUB_EXPONENT = Double.MIN_EXPONENT - 52 (SIGNIFICAND_WIDTH - 1); 53 54 /** 55 * Bias used in representing a {@code double} exponent. 56 */ 57 public static final int EXP_BIAS = 1023; 58 59 /** 60 * Bit mask to isolate the sign bit of a {@code double}. 61 */ 62 public static final long SIGN_BIT_MASK = 0x8000000000000000L; 63 64 /** 65 * Bit mask to isolate the exponent field of a 66 * {@code double}. 67 */ 68 public static final long EXP_BIT_MASK = 0x7FF0000000000000L; 69 70 /** 71 * Bit mask to isolate the significand field of a 72 * {@code double}. 73 */ 74 public static final long SIGNIF_BIT_MASK = 0x000FFFFFFFFFFFFFL; 75 76 static { 77 // verify bit masks cover all bit positions and that the bit 78 // masks are non-overlapping 79 assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0L) && 80 (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0L) && 81 ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0L) && 82 ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0L))); 83 } 84 }