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1/* Supplemental information about the floating-point formats.
2 Copyright (C) 2007 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2007.
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3, or (at your option)
8 any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18
19#ifndef _FLOATPLUS_H
20#define _FLOATPLUS_H
21
22#include <float.h>
23#include <limits.h>
24
25/* Number of bits in the mantissa of a floating-point number, including the
26 "hidden bit". */
27#if FLT_RADIX == 2
28# define FLT_MANT_BIT FLT_MANT_DIG
29# define DBL_MANT_BIT DBL_MANT_DIG
30# define LDBL_MANT_BIT LDBL_MANT_DIG
31#elif FLT_RADIX == 4
32# define FLT_MANT_BIT (FLT_MANT_DIG * 2)
33# define DBL_MANT_BIT (DBL_MANT_DIG * 2)
34# define LDBL_MANT_BIT (LDBL_MANT_DIG * 2)
35#elif FLT_RADIX == 16
36# define FLT_MANT_BIT (FLT_MANT_DIG * 4)
37# define DBL_MANT_BIT (DBL_MANT_DIG * 4)
38# define LDBL_MANT_BIT (LDBL_MANT_DIG * 4)
39#endif
40
41/* Bit mask that can be used to mask the exponent, as an unsigned number. */
42#define FLT_EXP_MASK ((FLT_MAX_EXP - FLT_MIN_EXP) | 7)
43#define DBL_EXP_MASK ((DBL_MAX_EXP - DBL_MIN_EXP) | 7)
44#define LDBL_EXP_MASK ((LDBL_MAX_EXP - LDBL_MIN_EXP) | 7)
45
46/* Number of bits used for the exponent of a floating-point number, including
47 the exponent's sign. */
48#define FLT_EXP_BIT \
49 (FLT_EXP_MASK < 0x100 ? 8 : \
50 FLT_EXP_MASK < 0x200 ? 9 : \
51 FLT_EXP_MASK < 0x400 ? 10 : \
52 FLT_EXP_MASK < 0x800 ? 11 : \
53 FLT_EXP_MASK < 0x1000 ? 12 : \
54 FLT_EXP_MASK < 0x2000 ? 13 : \
55 FLT_EXP_MASK < 0x4000 ? 14 : \
56 FLT_EXP_MASK < 0x8000 ? 15 : \
57 FLT_EXP_MASK < 0x10000 ? 16 : \
58 FLT_EXP_MASK < 0x20000 ? 17 : \
59 FLT_EXP_MASK < 0x40000 ? 18 : \
60 FLT_EXP_MASK < 0x80000 ? 19 : \
61 FLT_EXP_MASK < 0x100000 ? 20 : \
62 FLT_EXP_MASK < 0x200000 ? 21 : \
63 FLT_EXP_MASK < 0x400000 ? 22 : \
64 FLT_EXP_MASK < 0x800000 ? 23 : \
65 FLT_EXP_MASK < 0x1000000 ? 24 : \
66 FLT_EXP_MASK < 0x2000000 ? 25 : \
67 FLT_EXP_MASK < 0x4000000 ? 26 : \
68 FLT_EXP_MASK < 0x8000000 ? 27 : \
69 FLT_EXP_MASK < 0x10000000 ? 28 : \
70 FLT_EXP_MASK < 0x20000000 ? 29 : \
71 FLT_EXP_MASK < 0x40000000 ? 30 : \
72 FLT_EXP_MASK <= 0x7fffffff ? 31 : \
73 32)
74#define DBL_EXP_BIT \
75 (DBL_EXP_MASK < 0x100 ? 8 : \
76 DBL_EXP_MASK < 0x200 ? 9 : \
77 DBL_EXP_MASK < 0x400 ? 10 : \
78 DBL_EXP_MASK < 0x800 ? 11 : \
79 DBL_EXP_MASK < 0x1000 ? 12 : \
80 DBL_EXP_MASK < 0x2000 ? 13 : \
81 DBL_EXP_MASK < 0x4000 ? 14 : \
82 DBL_EXP_MASK < 0x8000 ? 15 : \
83 DBL_EXP_MASK < 0x10000 ? 16 : \
84 DBL_EXP_MASK < 0x20000 ? 17 : \
85 DBL_EXP_MASK < 0x40000 ? 18 : \
86 DBL_EXP_MASK < 0x80000 ? 19 : \
87 DBL_EXP_MASK < 0x100000 ? 20 : \
88 DBL_EXP_MASK < 0x200000 ? 21 : \
89 DBL_EXP_MASK < 0x400000 ? 22 : \
90 DBL_EXP_MASK < 0x800000 ? 23 : \
91 DBL_EXP_MASK < 0x1000000 ? 24 : \
92 DBL_EXP_MASK < 0x2000000 ? 25 : \
93 DBL_EXP_MASK < 0x4000000 ? 26 : \
94 DBL_EXP_MASK < 0x8000000 ? 27 : \
95 DBL_EXP_MASK < 0x10000000 ? 28 : \
96 DBL_EXP_MASK < 0x20000000 ? 29 : \
97 DBL_EXP_MASK < 0x40000000 ? 30 : \
98 DBL_EXP_MASK <= 0x7fffffff ? 31 : \
99 32)
100#define LDBL_EXP_BIT \
101 (LDBL_EXP_MASK < 0x100 ? 8 : \
102 LDBL_EXP_MASK < 0x200 ? 9 : \
103 LDBL_EXP_MASK < 0x400 ? 10 : \
104 LDBL_EXP_MASK < 0x800 ? 11 : \
105 LDBL_EXP_MASK < 0x1000 ? 12 : \
106 LDBL_EXP_MASK < 0x2000 ? 13 : \
107 LDBL_EXP_MASK < 0x4000 ? 14 : \
108 LDBL_EXP_MASK < 0x8000 ? 15 : \
109 LDBL_EXP_MASK < 0x10000 ? 16 : \
110 LDBL_EXP_MASK < 0x20000 ? 17 : \
111 LDBL_EXP_MASK < 0x40000 ? 18 : \
112 LDBL_EXP_MASK < 0x80000 ? 19 : \
113 LDBL_EXP_MASK < 0x100000 ? 20 : \
114 LDBL_EXP_MASK < 0x200000 ? 21 : \
115 LDBL_EXP_MASK < 0x400000 ? 22 : \
116 LDBL_EXP_MASK < 0x800000 ? 23 : \
117 LDBL_EXP_MASK < 0x1000000 ? 24 : \
118 LDBL_EXP_MASK < 0x2000000 ? 25 : \
119 LDBL_EXP_MASK < 0x4000000 ? 26 : \
120 LDBL_EXP_MASK < 0x8000000 ? 27 : \
121 LDBL_EXP_MASK < 0x10000000 ? 28 : \
122 LDBL_EXP_MASK < 0x20000000 ? 29 : \
123 LDBL_EXP_MASK < 0x40000000 ? 30 : \
124 LDBL_EXP_MASK <= 0x7fffffff ? 31 : \
125 32)
126
127/* Number of bits used for a floating-point number: the mantissa (not
128 counting the "hidden bit", since it may or may not be explicit), the
129 exponent, and the sign. */
130#define FLT_TOTAL_BIT ((FLT_MANT_BIT - 1) + FLT_EXP_BIT + 1)
131#define DBL_TOTAL_BIT ((DBL_MANT_BIT - 1) + DBL_EXP_BIT + 1)
132#define LDBL_TOTAL_BIT ((LDBL_MANT_BIT - 1) + LDBL_EXP_BIT + 1)
133
134/* Number of bytes used for a floating-point number.
135 This can be smaller than the 'sizeof'. For example, on i386 systems,
136 'long double' most often have LDBL_MANT_BIT = 64, LDBL_EXP_BIT = 16, hence
137 LDBL_TOTAL_BIT = 80 bits, i.e. 10 bytes of consecutive memory, but
138 sizeof (long double) = 12 or = 16. */
139#define SIZEOF_FLT ((FLT_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
140#define SIZEOF_DBL ((DBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
141#define SIZEOF_LDBL ((LDBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
142
143/* Verify that SIZEOF_FLT <= sizeof (float) etc. */
144typedef int verify_sizeof_flt[2 * (SIZEOF_FLT <= sizeof (float)) - 1];
145typedef int verify_sizeof_dbl[2 * (SIZEOF_DBL <= sizeof (double)) - 1];
146typedef int verify_sizeof_ldbl[2 * (SIZEOF_LDBL <= sizeof (long double)) - 1];
147
148#endif /* _FLOATPLUS_H */