1/* Supplemental information about the floating-point formats.
2   Copyright (C) 2007, 2009, 2010 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 Lesser General Public License as published by
7   the Free Software Foundation; either version 2, 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 Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser 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 */
149