The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/sys/ieee754.h

Version: -  FREEBSD  -  FREEBSD11  -  FREEBSD10  -  FREEBSD9  -  FREEBSD92  -  FREEBSD91  -  FREEBSD90  -  FREEBSD8  -  FREEBSD82  -  FREEBSD81  -  FREEBSD80  -  FREEBSD7  -  FREEBSD74  -  FREEBSD73  -  FREEBSD72  -  FREEBSD71  -  FREEBSD70  -  FREEBSD6  -  FREEBSD64  -  FREEBSD63  -  FREEBSD62  -  FREEBSD61  -  FREEBSD60  -  FREEBSD5  -  FREEBSD55  -  FREEBSD54  -  FREEBSD53  -  FREEBSD52  -  FREEBSD51  -  FREEBSD50  -  FREEBSD4  -  FREEBSD3  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*      $NetBSD: ieee754.h,v 1.3 2003/10/27 01:11:47 kleink Exp $       */
    2 
    3 /*
    4  * Copyright (c) 1992, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * This software was developed by the Computer Systems Engineering group
    8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
    9  * contributed to Berkeley.
   10  *
   11  * All advertising materials mentioning features or use of this software
   12  * must display the following acknowledgement:
   13  *      This product includes software developed by the University of
   14  *      California, Lawrence Berkeley Laboratory.
   15  *
   16  * Redistribution and use in source and binary forms, with or without
   17  * modification, are permitted provided that the following conditions
   18  * are met:
   19  * 1. Redistributions of source code must retain the above copyright
   20  *    notice, this list of conditions and the following disclaimer.
   21  * 2. Redistributions in binary form must reproduce the above copyright
   22  *    notice, this list of conditions and the following disclaimer in the
   23  *    documentation and/or other materials provided with the distribution.
   24  * 3. Neither the name of the University nor the names of its contributors
   25  *    may be used to endorse or promote products derived from this software
   26  *    without specific prior written permission.
   27  *
   28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   38  * SUCH DAMAGE.
   39  *
   40  *      @(#)ieee.h      8.1 (Berkeley) 6/11/93
   41  */
   42 
   43 /*
   44  * NOTICE: This is not a standalone file.  To use it, #include it in
   45  * your port's ieee.h header.
   46  */
   47 
   48 #ifndef _SYS_TYPES_H_
   49 #include <sys/types.h>
   50 #endif
   51 #include <machine/endian.h>
   52 
   53 
   54 /*
   55  * <sys/ieee754.h> defines the layout of IEEE 754 floating point types.
   56  * Only single-precision and double-precision types are defined here;
   57  * extended types, if available, are defined in the machine-dependent
   58  * header.
   59  */
   60 
   61 /*
   62  * Define the number of bits in each fraction and exponent.
   63  *
   64  *                   k           k+1
   65  * Note that  1.0 x 2  == 0.1 x 2      and that denorms are represented
   66  *
   67  *                                        (-exp_bias+1)
   68  * as fractions that look like 0.fffff x 2             .  This means that
   69  *
   70  *                       -126
   71  * the number 0.10000 x 2    , for instance, is the same as the normalized
   72  *
   73  *              -127                       -128
   74  * float 1.0 x 2    .  Thus, to represent 2    , we need one leading zero
   75  *
   76  *                                -129
   77  * in the fraction; to represent 2    , we need two, and so on.  This
   78  *
   79  *                                                   (-exp_bias-fracbits+1)
   80  * implies that the smallest denormalized number is 2
   81  *
   82  * for whichever format we are talking about: for single precision, for
   83  *
   84  *                                              -126            -149
   85  * instance, we get .00000000000000000000001 x 2    , or 1.0 x 2    , and
   86  *
   87  * -149 == -127 - 23 + 1.
   88  */
   89 #define SNG_EXPBITS     8
   90 #define SNG_FRACBITS    23
   91 
   92 #define DBL_EXPBITS     11
   93 #define DBL_FRACBITS    52
   94 
   95 struct ieee_single {
   96 #if _BYTE_ORDER == _BIG_ENDIAN
   97         u_int   sng_sign:1;
   98         u_int   sng_exp:8;
   99         u_int   sng_frac:23;
  100 #else
  101         u_int   sng_frac:23;
  102         u_int   sng_exp:8;
  103         u_int   sng_sign:1;
  104 #endif
  105 };
  106 
  107 struct ieee_double {
  108 #if _BYTE_ORDER == _BIG_ENDIAN
  109         u_int   dbl_sign:1;
  110         u_int   dbl_exp:11;
  111         u_int   dbl_frach:20;
  112         u_int   dbl_fracl;
  113 #else
  114         u_int   dbl_fracl;
  115         u_int   dbl_frach:20;
  116         u_int   dbl_exp:11;
  117         u_int   dbl_sign:1;
  118 #endif
  119 };
  120 
  121 /*
  122  * Floats whose exponent is in [1..INFNAN) (of whatever type) are
  123  * `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
  124  * Floats whose exponent is zero are either zero (iff all fraction
  125  * bits are zero) or subnormal values.
  126  *
  127  * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
  128  * high fraction; if the bit is set, it is a `quiet NaN'.
  129  */
  130 #define SNG_EXP_INFNAN  255
  131 #define DBL_EXP_INFNAN  2047
  132 
  133 #if 0
  134 #define SNG_QUIETNAN    (1 << 22)
  135 #define DBL_QUIETNAN    (1 << 19)
  136 #endif
  137 
  138 /*
  139  * Exponent biases.
  140  */
  141 #define SNG_EXP_BIAS    127
  142 #define DBL_EXP_BIAS    1023
  143 
  144 /*
  145  * Convenience data structures.
  146  */
  147 union ieee_single_u {
  148         float                   sngu_f;
  149         struct ieee_single      sngu_sng;
  150 };
  151 
  152 union ieee_double_u {
  153         double                  dblu_d;
  154         struct ieee_double      dblu_dbl;
  155 };

Cache object: d7586575d06e97aab730ff16d61dd32f


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.