| 1 | /*
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| 2 | * Copyright (c) 2012 Adam Hraska
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | #ifndef IEEE_DOUBLE_H_
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| 30 | #define IEEE_DOUBLE_H_
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| 31 |
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| 32 | #include <stdint.h>
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| 33 | #include <stdbool.h>
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| 34 |
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| 35 | /** Represents a non-negative floating point number: significand * 2^exponent */
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| 36 | typedef struct fp_num_t_tag {
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| 37 | /** Significand (aka mantissa). */
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| 38 | uint64_t significand;
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| 39 | /** Binary exponent. */
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| 40 | int exponent;
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| 41 | } fp_num_t;
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| 42 |
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| 43 | /** Double number description according to IEEE 754. */
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| 44 | typedef struct ieee_double_t_tag {
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| 45 | /** The number is a NaN or infinity. */
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| 46 | bool is_special;
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| 47 | /** Not a number. */
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| 48 | bool is_nan;
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| 49 | bool is_negative;
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| 50 | /** The number denoted infinity. */
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| 51 | bool is_infinity;
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| 52 | /** The number could not be represented as a normalized double. */
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| 53 | bool is_denormal;
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| 54 | /**
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| 55 | * The predecessor double is closer than the successor. This happens
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| 56 | * if a normal number is of the form 2^k and it is not the smallest
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| 57 | * normal number.
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| 58 | */
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| 59 | bool is_accuracy_step;
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| 60 | /**
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| 61 | * If !is_special the double's value is:
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| 62 | * pos_val.significand * 2^pos_val.exponent
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| 63 | */
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| 64 | fp_num_t pos_val;
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| 65 | } ieee_double_t;
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| 66 |
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| 67 | extern ieee_double_t extract_ieee_double(double);
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| 68 |
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| 69 | #endif
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