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 float} type. 31 * 32 * @author Joseph D. Darcy 33 */ 34 35 public class FloatConsts { 36 /** 37 * Don't let anyone instantiate this class. 38 */ FloatConsts()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} 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} subnormal 76 * value would have if it could be normalized. 77 */ 78 public static final int MIN_SUB_EXPONENT = Float.MIN_EXPONENT - 79 (SIGNIFICAND_WIDTH - 1); 80 81 /** 82 * Bias used in representing a {@code float} exponent. 83 */ 84 public static final int EXP_BIAS = 127; 85 86 /** 87 * Bit mask to isolate the sign bit of a {@code float}. 88 */ 89 public static final int SIGN_BIT_MASK = 0x80000000; 90 91 /** 92 * Bit mask to isolate the exponent field of a 93 * {@code float}. 94 */ 95 public static final int EXP_BIT_MASK = 0x7F800000; 96 97 /** 98 * Bit mask to isolate the significand field of a 99 * {@code float}. 100 */ 101 public static final int SIGNIF_BIT_MASK = 0x007FFFFF; 102 103 static { 104 // verify bit masks cover all bit positions and that the bit 105 // masks are non-overlapping 106 assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0) && 107 (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0) && 108 ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0) && 109 ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0))); 110 } 111 } 112