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ieee.h revision 1.10 
      1 /* $NetBSD: ieee.h,v 1.10 2014/01/29 01:34:44 matt Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Matt Thomas of 3am Software Foundry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * ieee.h defines the machine-dependent layout of the machine's IEEE
     34  * floating point.  It does *not* define (yet?) any of the rounding
     35  * mode bits, exceptions, and so forth.
     36  */
     37 
     38 #ifndef _ARM_IEEE_H_
     39 #define _ARM_IEEE_H_
     40 
     41 #include <sys/ieee754.h>
     42 
     43 #if 0
     44 #define	SNG_QUIETNAN	(1 << 22)
     45 #define	DBL_QUIETNAN	(1 << 19)
     46 #endif
     47 
     48 #ifdef __ARM_PCS_AAPCS64
     49 
     50 /*
     51  * The AArch64 architecture defines the following IEEE 754 compliant
     52  * 128-bit extended-precision format.
     53  */
     54 
     55 #define	EXT_EXPBITS	15
     56 #define EXT_FRACHBITS	48
     57 #define	EXT_FRACLBITS	64
     58 #define	EXT_FRACBITS	(EXT_FRACLBITS + EXT_FRACHBITS)
     59 
     60 #define	EXT_TO_ARRAY32(u, a) do {				\
     61 	(a)[0] = (uint32_t)((u).extu_ext.ext_fracl >>  0);	\
     62 	(a)[1] = (uint32_t)((u).extu_ext.ext_fracl >> 32);	\
     63 	(a)[2] = (uint32_t)((u).extu_ext.ext_frach >>  0);	\
     64 	(a)[3] = (uint32_t)((u).extu_ext.ext_frach >> 32);	\
     65 } while(/*CONSTCOND*/0)
     66 
     67 struct ieee_ext {
     68 #ifdef __AARCH64EB__
     69 	uint64_t	ext_sign:1;
     70 	uint64_t	ext_exp:EXT_EXPBITS;
     71 	uint64_t	ext_frach:EXT_FRACHBITS;
     72 	uint64_t	ext_fracl;
     73 #else
     74 	uint64_t	ext_fracl;
     75 	uint64_t	ext_frach:EXT_FRACHBITS;
     76 	uint64_t	ext_exp:EXT_EXPBITS;
     77 	uint64_t	ext_sign:1;
     78 #endif
     79 };
     80 
     81 /*
     82  * Floats whose exponent is in [1..INFNAN) (of whatever type) are
     83  * `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
     84  * Floats whose exponent is zero are either zero (iff all fraction
     85  * bits are zero) or subnormal values.
     86  *
     87  * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
     88  * high fraction; if the bit is set, it is a `quiet NaN'.
     89  */
     90 #define	EXT_EXP_INFNAN	0x7fff
     91 #define	EXT_EXP_INF	0x7fff
     92 #define	EXT_EXP_NAN	0x7fff
     93 
     94 #if 0
     95 #define	EXT_QUIETNAN	(1 << 15)
     96 #endif
     97 
     98 /*
     99  * Exponent biases.
    100  */
    101 #define	EXT_EXP_BIAS	16383
    102 
    103 /*
    104  * Convenience data structures.
    105  */
    106 union ieee_ext_u {
    107 	long double		extu_ld;
    108 	struct ieee_ext		extu_ext;
    109 };
    110 
    111 #define extu_exp	extu_ext.ext_exp
    112 #define extu_sign	extu_ext.ext_sign
    113 #define extu_fracl	extu_ext.ext_fracl
    114 #define extu_frach	extu_ext.ext_frach
    115 
    116 #define LDBL_IMPLICIT_NBIT	1	/* our NBIT is implicit */
    117 
    118 #endif /* __ARM_PCS_AAPCS64 */
    119 
    120 #endif /* !_ARM_IEEE_H_ */
    121