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root/uspace/lib/c/include/ieee_double.h

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/*
 * Copyright (c) 2012 Adam Hraska
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef IEEE_DOUBLE_H_
#define IEEE_DOUBLE_H_

#include <stdint.h>
#include <stdbool.h>

/** Represents a non-negative floating point number: significand * 2^exponent */
typedef struct fp_num_t_tag {
        /** Significand (aka mantissa). */
        uint64_t significand;
        /** Binary exponent. */
        int exponent;
} fp_num_t;

/** Double number description according to IEEE 754. */
typedef struct ieee_double_t_tag {
        /** The number is a NaN or infinity. */
        bool is_special;
        /** Not a number. */
        bool is_nan;
        bool is_negative;
        /** The number denoted infinity. */
        bool is_infinity;
        /** The number could not be represented as a normalized double. */
        bool is_denormal;
        /**
         * The predecessor double is closer than the successor. This happens
         * if a normal number is of the form 2^k and it is not the smallest
         * normal number.
         */
        bool is_accuracy_step;
        /**
         * If !is_special the double's value is:
         *   pos_val.significand * 2^pos_val.exponent
         */
        fp_num_t pos_val;
} ieee_double_t;

extern ieee_double_t extract_ieee_double(double);

#endif

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