DoubleConsts.java revision 10533:41dd7c59dd6f
1/* 2 * Copyright (c) 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24/** 25 * Common library for additional constants of the {@code double} type. 26 */ 27public final class DoubleConsts { 28 /** 29 * Don't let anyone instantiate this class. 30 */ 31 private DoubleConsts() {} 32 33 /** 34 * Bias used in representing a {@code double} exponent. 35 */ 36 public static final int EXP_BIAS = 1023; 37 38 /** 39 * Bit mask to isolate the exponent field of a {@code double}. 40 */ 41 public static final long EXP_BIT_MASK = 0x7FF0000000000000L; 42 43 /** 44 * Bit mask to isolate the sign bit of a {@code double}. 45 */ 46 public static final long SIGN_BIT_MASK = 0x8000000000000000L; 47 48 /** 49 * Bit mask to isolate the significand field of a {@code double}. 50 */ 51 public static final long SIGNIF_BIT_MASK = 0x000FFFFFFFFFFFFFL; 52 53 /** 54 * The number of logical bits in the significand of a 55 * {@code double} number, including the implicit bit. 56 */ 57 public static final int SIGNIFICAND_WIDTH = 53; 58 59 /** 60 * The exponent the smallest positive {@code double} 61 * subnormal value would have if it could be normalized. 62 */ 63 public static final int MIN_SUB_EXPONENT = Double.MIN_EXPONENT - 64 (SIGNIFICAND_WIDTH - 1); 65 66 static { 67 // verify bit masks cover all bit positions and that the bit 68 // masks are non-overlapping 69 assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0L) && 70 (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0L) && 71 ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0L) && 72 ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0L))); 73 } 74} 75