166 lines
4.8 KiB
C
166 lines
4.8 KiB
C
/* $NetBSD: ieee754.h,v 1.4 2003/10/27 02:30:26 simonb Exp $ */
|
|
|
|
/*-
|
|
* SPDX-License-Identifier: BSD-3-Clause
|
|
*
|
|
* Copyright (c) 1992, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This software was developed by the Computer Systems Engineering group
|
|
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
|
|
* contributed to Berkeley.
|
|
*
|
|
* All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Lawrence Berkeley Laboratory.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. 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.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
|
|
*
|
|
* @(#)ieee.h 8.1 (Berkeley) 6/11/93
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* NOTICE: This is not a standalone file. To use it, #include it in
|
|
* your port's ieee.h header.
|
|
*/
|
|
|
|
#include <machine/endian.h>
|
|
|
|
/*
|
|
* <sys/ieee754.h> defines the layout of IEEE 754 floating point types.
|
|
* Only single-precision and double-precision types are defined here;
|
|
* extended types, if available, are defined in the machine-dependent
|
|
* header.
|
|
*/
|
|
|
|
/*
|
|
* Define the number of bits in each fraction and exponent.
|
|
*
|
|
* k k+1
|
|
* Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
|
|
*
|
|
* (-exp_bias+1)
|
|
* as fractions that look like 0.fffff x 2 . This means that
|
|
*
|
|
* -126
|
|
* the number 0.10000 x 2 , for instance, is the same as the normalized
|
|
*
|
|
* -127 -128
|
|
* float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
|
|
*
|
|
* -129
|
|
* in the fraction; to represent 2 , we need two, and so on. This
|
|
*
|
|
* (-exp_bias-fracbits+1)
|
|
* implies that the smallest denormalized number is 2
|
|
*
|
|
* for whichever format we are talking about: for single precision, for
|
|
*
|
|
* -126 -149
|
|
* instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
|
|
*
|
|
* -149 == -127 - 23 + 1.
|
|
*/
|
|
#define SNG_EXPBITS 8
|
|
#define SNG_FRACBITS 23
|
|
|
|
#define DBL_EXPBITS 11
|
|
#define DBL_FRACBITS 52
|
|
|
|
#if defined(__VFP_FP__) || defined(__ARM_EABI__)
|
|
#define _IEEE_WORD_ORDER _BYTE_ORDER
|
|
#else
|
|
#define _IEEE_WORD_ORDER _BIG_ENDIAN
|
|
#endif
|
|
|
|
struct ieee_single {
|
|
#if _BYTE_ORDER == _BIG_ENDIAN
|
|
u_int sng_sign:1;
|
|
u_int sng_exp:8;
|
|
u_int sng_frac:23;
|
|
#else
|
|
u_int sng_frac:23;
|
|
u_int sng_exp:8;
|
|
u_int sng_sign:1;
|
|
#endif
|
|
};
|
|
|
|
struct ieee_double {
|
|
#if _BYTE_ORDER == _BIG_ENDIAN
|
|
u_int dbl_sign:1;
|
|
u_int dbl_exp:11;
|
|
u_int dbl_frach:20;
|
|
u_int dbl_fracl;
|
|
#else
|
|
#if _IEEE_WORD_ORDER == _LITTLE_ENDIAN
|
|
u_int dbl_fracl;
|
|
#endif
|
|
u_int dbl_frach:20;
|
|
u_int dbl_exp:11;
|
|
u_int dbl_sign:1;
|
|
#if _IEEE_WORD_ORDER == _BIG_ENDIAN
|
|
u_int dbl_fracl;
|
|
#endif
|
|
#endif
|
|
};
|
|
|
|
/*
|
|
* Floats whose exponent is in [1..INFNAN) (of whatever type) are
|
|
* `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
|
|
* Floats whose exponent is zero are either zero (iff all fraction
|
|
* bits are zero) or subnormal values.
|
|
*
|
|
* A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
|
|
* high fraction; if the bit is set, it is a `quiet NaN'.
|
|
*/
|
|
#define SNG_EXP_INFNAN 255
|
|
#define DBL_EXP_INFNAN 2047
|
|
|
|
#if 0
|
|
#define SNG_QUIETNAN (1 << 22)
|
|
#define DBL_QUIETNAN (1 << 19)
|
|
#endif
|
|
|
|
/*
|
|
* Exponent biases.
|
|
*/
|
|
#define SNG_EXP_BIAS 127
|
|
#define DBL_EXP_BIAS 1023
|
|
|
|
/*
|
|
* Convenience data structures.
|
|
*/
|
|
union ieee_single_u {
|
|
float sngu_f;
|
|
struct ieee_single sngu_sng;
|
|
};
|
|
|
|
union ieee_double_u {
|
|
double dblu_d;
|
|
struct ieee_double dblu_dbl;
|
|
};
|