xref: /illumos-gate/usr/src/lib/libc/port/fp/fpparts.h (revision 1da57d55)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * Macros to pull apart parts of single and  double precision
32  * floating point numbers in IEEE format
33  * Be sure to include /usr/include/values.h before including
34  * this file to get the required definition of _IEEE
35  */
36 
37 #if _IEEE
38 #if defined(__sparc)
39 /* byte order with high order bits at lowest address */
40 
41 /* double precision */
42 typedef  union {
43 	struct {
44 		unsigned  sign	:1;
45 		unsigned  exp	:11;
46 		unsigned  hi	:20;
47 		unsigned  lo	:32;
48 	} fparts;
49 	struct {
50 		unsigned  sign	:1;
51 		unsigned  exp	:11;
52 		unsigned  qnan_bit	:1;
53 		unsigned  hi	:19;
54 		unsigned  lo	:32;
55 	} nparts;
56 	struct {
57 		unsigned hi;
58 		unsigned lo;
59 	} fwords;
60 	double	d;
61 } _dval;
62 
63 /* single precision */
64 typedef  union {
65 	struct {
66 		unsigned sign	:1;
67 		unsigned exp	:8;
68 		unsigned fract	:23;
69 	} fparts;
70 	struct {
71 		unsigned sign	:1;
72 		unsigned exp	:8;
73 		unsigned qnan_bit	:1;
74 		unsigned fract	:22;
75 	} nparts;
76 	unsigned long	fword;
77 	float	f;
78 } _fval;
79 
80 
81 #elif defined(__i386) || defined(__amd64)
82 /* byte order with low order bits at lowest address */
83 
84 /* double precision */
85 typedef  union {
86 	struct {
87 		unsigned  lo	:32;
88 		unsigned  hi	:20;
89 		unsigned  exp	:11;
90 		unsigned  sign	:1;
91 	} fparts;
92 	struct {
93 		unsigned  lo	:32;
94 		unsigned  hi	:19;
95 		unsigned  qnan_bit	:1;
96 		unsigned  exp	:11;
97 		unsigned  sign	:1;
98 	} nparts;
99 	struct {
100 		unsigned  lo	:32;
101 		unsigned  hi	:32;
102 	} fwords;
103 	double	d;
104 } _dval;
105 
106 /* single precision */
107 typedef  union {
108 	struct {
109 		unsigned fract	:23;
110 		unsigned exp	:8;
111 		unsigned sign	:1;
112 	} fparts;
113 	struct {
114 		unsigned fract	:22;
115 		unsigned qnan_bit	:1;
116 		unsigned exp	:8;
117 		unsigned sign	:1;
118 	} nparts;
119 	unsigned long	fword;
120 	float	f;
121 } _fval;
122 #endif
123 
124 /* parts of a double precision floating point number */
125 #define	SIGNBIT(X)	(((_dval *)&(X))->fparts.sign)
126 #define	EXPONENT(X)	(((_dval *)&(X))->fparts.exp)
127 
128 #define	HIFRACTION(X)	(((_dval *)&(X))->fparts.hi)
129 #define	LOFRACTION(X)	(((_dval *)&(X))->fparts.lo)
130 #define	QNANBIT(X)	(((_dval *)&(X))->nparts.qnan_bit)
131 #define	HIWORD(X)	(((_dval *)&(X))->fwords.hi)
132 #define	LOWORD(X)	(((_dval *)&(X))->fwords.lo)
133 
134 #define	MAXEXP	0x7ff /* maximum exponent of double */
135 #define	ISMAXEXP(X)	((EXPONENT(X)) == MAXEXP)
136 
137 /* macros used to create quiet NaNs as return values */
138 #define	SETQNAN(X)	((((_dval *)&(X))->nparts.qnan_bit) = 0x1)
139 #define	HIQNAN(X)	((HIWORD(X)) = 0x7ff80000)
140 #define	LOQNAN(X)	((((_dval *)&(X))->fwords.lo) = 0x0)
141 
142 /* macros used to extract parts of single precision values */
143 #define	FSIGNBIT(X)	(((_fval *)&(X))->fparts.sign)
144 #define	FEXPONENT(X)	(((_fval *)&(X))->fparts.exp)
145 #define	FFRACTION(X)	(((_fval *)&(X))->fparts.fract)
146 
147 #define	FWORD(X)	(((_fval *)&(X))->fword)
148 #define	FQNANBIT(X)	(((_fval *)&(X))->nparts.qnan_bit)
149 #define	MAXEXPF	255 /* maximum exponent of single */
150 #define	FISMAXEXP(X)	((FEXPONENT(X)) == MAXEXPF)
151 
152 #endif  /* _IEEE */
153