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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * particular file as subject to the "Classpath" exception as provided
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package jdk.internal.math;

import static java.lang.Float.MIN_EXPONENT;
import static java.lang.Float.PRECISION;
import static java.lang.Float.SIZE;

/**
 * This class contains additional constants documenting limits of the
 * {@code float} type.
 *
 * @author Joseph D. Darcy
 */

public class FloatConsts {
    /**
     * Don't let anyone instantiate this class.
     */
    private FloatConsts() {}

    public static final float POSITIVE_INFINITY = java.lang.Float.POSITIVE_INFINITY;
    public static final float NEGATIVE_INFINITY = java.lang.Float.NEGATIVE_INFINITY;
    public static final float NaN = java.lang.Float.NaN;
    public static final float MAX_VALUE = java.lang.Float.MAX_VALUE;
    public static final float MIN_VALUE = java.lang.Float.MIN_VALUE;

    /**
     * A constant holding the smallest positive normal value of type
     * <code>float</code>, 2<sup>-126</sup>.  It is equal to the value
     * returned by <code>Float.intBitsToFloat(0x00800000)</code>.
     */
    public static final float   MIN_NORMAL      = 1.17549435E-38f;

    /**
     * The number of logical bits in the significand of a
     * {@code float} number, including the implicit bit.
     */
    public static final int SIGNIFICAND_WIDTH = PRECISION;

    /**
     * Maximum exponent a finite <code>float</code> number may have.
     * It is equal to the value returned by
     * <code>Math.ilogb(Float.MAX_VALUE)</code>.
     */
    public static final int     MAX_EXPONENT    = 127;

    /**
     * Minimum exponent a normalized <code>float</code> number may
     * have.  It is equal to the value returned by
     * <code>Math.ilogb(Float.MIN_NORMAL)</code>.
     */
    public static final int     MIN_EXPONENT    = -126;

    /**
     * The exponent the smallest positive {@code float}
     * subnormal value would have if it could be normalized.
     */
    public static final int MIN_SUB_EXPONENT =
            MIN_EXPONENT - (SIGNIFICAND_WIDTH - 1); // -149

    /**
     * Bias used in representing a {@code float} exponent.
     */
    public static final int EXP_BIAS =
            (1 << (SIZE - SIGNIFICAND_WIDTH - 1)) - 1; // 127

    /**
     * Bit mask to isolate the sign bit of a {@code float}.
     */
    public static final int SIGN_BIT_MASK = 1 << (SIZE - 1);

    /**
     * Bit mask to isolate the exponent field of a {@code float}.
     */
    public static final int EXP_BIT_MASK =
            ((1 << (SIZE - SIGNIFICAND_WIDTH)) - 1) << (SIGNIFICAND_WIDTH - 1);

    /**
     * Bit mask to isolate the significand field of a {@code float}.
     */
    public static final int SIGNIF_BIT_MASK = (1 << (SIGNIFICAND_WIDTH - 1)) - 1;

    /**
     * Bit mask to isolate the magnitude bits (combined exponent and
     * significand fields) of a {@code float}.
     */
    public static final int MAG_BIT_MASK = EXP_BIT_MASK | SIGNIF_BIT_MASK;

    static {
        // verify bit masks cover all bit positions and that the bit
        // masks are non-overlapping
        assert(((SIGN_BIT_MASK | EXP_BIT_MASK | SIGNIF_BIT_MASK) == ~0) &&
               (((SIGN_BIT_MASK & EXP_BIT_MASK) == 0) &&
                ((SIGN_BIT_MASK & SIGNIF_BIT_MASK) == 0) &&
                ((EXP_BIT_MASK & SIGNIF_BIT_MASK) == 0)) &&
                ((SIGN_BIT_MASK | MAG_BIT_MASK) == ~0));
    }
}