219 lines
6.5 KiB
C
219 lines
6.5 KiB
C
/* $NetBSD: ieee754.h,v 1.16 2016/06/03 15:15:22 dholland Exp $ */
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/*
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This software was developed by the Computer Systems Engineering group
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* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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* contributed to Berkeley.
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*
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* All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Lawrence Berkeley Laboratory.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ieee.h 8.1 (Berkeley) 6/11/93
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*/
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#ifndef _SYS_IEEE754_H_
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#define _SYS_IEEE754_H_
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/*
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* NOTICE: This is not a standalone file. To use it, #include it in
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* your port's ieee.h header.
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*/
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#include <machine/endian.h>
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/*
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* <sys/ieee754.h> defines the layout of IEEE 754 floating point types.
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* Only single-precision and double-precision types are defined here;
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* 128-bit long doubles are define here IFF __HAVE_LONG_DOUBLE equals 128.
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* Otherwise extended types, if available, are defined in the machine-dependent
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* header.
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*/
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/*
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* Define the number of bits in each fraction and exponent.
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*
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* k k+1
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* Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
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*
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* (-exp_bias+1)
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* as fractions that look like 0.fffff x 2 . This means that
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*
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* -126
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* the number 0.10000 x 2 , for instance, is the same as the normalized
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*
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* -127 -128
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* float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
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*
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* -129
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* in the fraction; to represent 2 , we need two, and so on. This
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*
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* (-exp_bias-fracbits+1)
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* implies that the smallest denormalized number is 2
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*
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* for whichever format we are talking about: for single precision, for
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*
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* -126 -149
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* instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
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*
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* -149 == -127 - 23 + 1.
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*/
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#define SNG_EXPBITS 8
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#define SNG_FRACBITS 23
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struct ieee_single {
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#if _BYTE_ORDER == _BIG_ENDIAN
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unsigned int sng_sign:1;
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unsigned int sng_exp:SNG_EXPBITS;
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unsigned int sng_frac:SNG_FRACBITS;
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#else
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unsigned int sng_frac:SNG_FRACBITS;
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unsigned int sng_exp:SNG_EXPBITS;
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unsigned int sng_sign:1;
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#endif
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};
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#define DBL_EXPBITS 11
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#define DBL_FRACHBITS 20
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#define DBL_FRACLBITS 32
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#define DBL_FRACBITS (DBL_FRACHBITS + DBL_FRACLBITS)
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struct ieee_double {
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#if _BYTE_ORDER == _BIG_ENDIAN
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unsigned int dbl_sign:1;
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unsigned int dbl_exp:DBL_EXPBITS;
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unsigned int dbl_frach:DBL_FRACHBITS;
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unsigned int dbl_fracl:DBL_FRACLBITS;
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#else
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unsigned int dbl_fracl:DBL_FRACLBITS;
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unsigned int dbl_frach:DBL_FRACHBITS;
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unsigned int dbl_exp:DBL_EXPBITS;
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unsigned int dbl_sign:1;
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#endif
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};
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#if __HAVE_LONG_DOUBLE + 0 == 128
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#define EXT_EXPBITS 15
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#define EXT_FRACHBITS 48
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#define EXT_FRACLBITS 64
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#define EXT_FRACBITS (EXT_FRACLBITS + EXT_FRACHBITS)
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#define EXT_TO_ARRAY32(u, a) do { \
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(a)[0] = (uint32_t)((u).extu_ext.ext_fracl >> 0); \
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(a)[1] = (uint32_t)((u).extu_ext.ext_fracl >> 32); \
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(a)[2] = (uint32_t)((u).extu_ext.ext_frach >> 0); \
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(a)[3] = (uint32_t)((u).extu_ext.ext_frach >> 32); \
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} while(/*CONSTCOND*/0)
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struct ieee_ext {
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#if _BYTE_ORDER == _BIG_ENDIAN
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uint64_t ext_sign:1;
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uint64_t ext_exp:EXT_EXPBITS;
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uint64_t ext_frach:EXT_FRACHBITS;
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uint64_t ext_fracl;
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#else
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uint64_t ext_fracl;
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uint64_t ext_frach:EXT_FRACHBITS;
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uint64_t ext_exp:EXT_EXPBITS;
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uint64_t ext_sign:1;
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#endif
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};
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#endif /* __HAVE_LONG_DOUBLE == 128 */
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/*
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* Floats whose exponent is in [1..INFNAN) (of whatever type) are
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* `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
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* Floats whose exponent is zero are either zero (iff all fraction
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* bits are zero) or subnormal values.
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*
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* At least one `signalling NaN' and one `quiet NaN' value must be
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* implemented. It is left to the architecture to specify how to
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* distinguish between these.
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*/
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#define SNG_EXP_INFNAN 255
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#define DBL_EXP_INFNAN 2047
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#if __HAVE_LONG_DOUBLE + 0 == 128
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#define EXT_EXP_INFNAN 0x7fff
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#endif
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/*
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* Exponent biases.
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*/
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#define SNG_EXP_BIAS 127
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#define DBL_EXP_BIAS 1023
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#if __HAVE_LONG_DOUBLE + 0 == 128
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#define EXT_EXP_BIAS 16383
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#endif
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/*
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* Convenience data structures.
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*/
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union ieee_single_u {
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float sngu_f;
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struct ieee_single sngu_sng;
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};
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#define sngu_sign sngu_sng.sng_sign
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#define sngu_exp sngu_sng.sng_exp
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#define sngu_frac sngu_sng.sng_frac
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#define SNGU_ZEROFRAC_P(u) ((u).sngu_frac != 0)
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union ieee_double_u {
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double dblu_d;
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struct ieee_double dblu_dbl;
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};
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#define dblu_sign dblu_dbl.dbl_sign
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#define dblu_exp dblu_dbl.dbl_exp
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#define dblu_frach dblu_dbl.dbl_frach
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#define dblu_fracl dblu_dbl.dbl_fracl
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#define DBLU_ZEROFRAC_P(u) (((u).dblu_frach|(u).dblu_fracl) != 0)
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#if __HAVE_LONG_DOUBLE + 0 == 128
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union ieee_ext_u {
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long double extu_ld;
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struct ieee_ext extu_ext;
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};
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#define extu_exp extu_ext.ext_exp
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#define extu_sign extu_ext.ext_sign
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#define extu_fracl extu_ext.ext_fracl
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#define extu_frach extu_ext.ext_frach
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#define EXTU_ZEROFRAC_P(u) (((u).extu_frach|(u).extu_fracl) != 0)
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#ifndef LDBL_NBIT
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#define LDBL_IMPLICIT_NBIT 1 /* our NBIT is implicit */
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#endif
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#endif /* __HAVE_LONG_DOUBLE */
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#endif /* _SYS_IEEE754_H_ */
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