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Diffstat (limited to 'lib/float+.h')
| -rw-r--r-- | lib/float+.h | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/lib/float+.h b/lib/float+.h new file mode 100644 index 0000000..4de25a9 --- /dev/null +++ b/lib/float+.h @@ -0,0 +1,148 @@ +/* Supplemental information about the floating-point formats. + Copyright (C) 2007 Free Software Foundation, Inc. + Written by Bruno Haible <bruno@clisp.org>, 2007. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +#ifndef _FLOATPLUS_H +#define _FLOATPLUS_H + +#include <float.h> +#include <limits.h> + +/* Number of bits in the mantissa of a floating-point number, including the + "hidden bit". */ +#if FLT_RADIX == 2 +# define FLT_MANT_BIT FLT_MANT_DIG +# define DBL_MANT_BIT DBL_MANT_DIG +# define LDBL_MANT_BIT LDBL_MANT_DIG +#elif FLT_RADIX == 4 +# define FLT_MANT_BIT (FLT_MANT_DIG * 2) +# define DBL_MANT_BIT (DBL_MANT_DIG * 2) +# define LDBL_MANT_BIT (LDBL_MANT_DIG * 2) +#elif FLT_RADIX == 16 +# define FLT_MANT_BIT (FLT_MANT_DIG * 4) +# define DBL_MANT_BIT (DBL_MANT_DIG * 4) +# define LDBL_MANT_BIT (LDBL_MANT_DIG * 4) +#endif + +/* Bit mask that can be used to mask the exponent, as an unsigned number. */ +#define FLT_EXP_MASK ((FLT_MAX_EXP - FLT_MIN_EXP) | 7) +#define DBL_EXP_MASK ((DBL_MAX_EXP - DBL_MIN_EXP) | 7) +#define LDBL_EXP_MASK ((LDBL_MAX_EXP - LDBL_MIN_EXP) | 7) + +/* Number of bits used for the exponent of a floating-point number, including + the exponent's sign. */ +#define FLT_EXP_BIT \ + (FLT_EXP_MASK < 0x100 ? 8 : \ + FLT_EXP_MASK < 0x200 ? 9 : \ + FLT_EXP_MASK < 0x400 ? 10 : \ + FLT_EXP_MASK < 0x800 ? 11 : \ + FLT_EXP_MASK < 0x1000 ? 12 : \ + FLT_EXP_MASK < 0x2000 ? 13 : \ + FLT_EXP_MASK < 0x4000 ? 14 : \ + FLT_EXP_MASK < 0x8000 ? 15 : \ + FLT_EXP_MASK < 0x10000 ? 16 : \ + FLT_EXP_MASK < 0x20000 ? 17 : \ + FLT_EXP_MASK < 0x40000 ? 18 : \ + FLT_EXP_MASK < 0x80000 ? 19 : \ + FLT_EXP_MASK < 0x100000 ? 20 : \ + FLT_EXP_MASK < 0x200000 ? 21 : \ + FLT_EXP_MASK < 0x400000 ? 22 : \ + FLT_EXP_MASK < 0x800000 ? 23 : \ + FLT_EXP_MASK < 0x1000000 ? 24 : \ + FLT_EXP_MASK < 0x2000000 ? 25 : \ + FLT_EXP_MASK < 0x4000000 ? 26 : \ + FLT_EXP_MASK < 0x8000000 ? 27 : \ + FLT_EXP_MASK < 0x10000000 ? 28 : \ + FLT_EXP_MASK < 0x20000000 ? 29 : \ + FLT_EXP_MASK < 0x40000000 ? 30 : \ + FLT_EXP_MASK <= 0x7fffffff ? 31 : \ + 32) +#define DBL_EXP_BIT \ + (DBL_EXP_MASK < 0x100 ? 8 : \ + DBL_EXP_MASK < 0x200 ? 9 : \ + DBL_EXP_MASK < 0x400 ? 10 : \ + DBL_EXP_MASK < 0x800 ? 11 : \ + DBL_EXP_MASK < 0x1000 ? 12 : \ + DBL_EXP_MASK < 0x2000 ? 13 : \ + DBL_EXP_MASK < 0x4000 ? 14 : \ + DBL_EXP_MASK < 0x8000 ? 15 : \ + DBL_EXP_MASK < 0x10000 ? 16 : \ + DBL_EXP_MASK < 0x20000 ? 17 : \ + DBL_EXP_MASK < 0x40000 ? 18 : \ + DBL_EXP_MASK < 0x80000 ? 19 : \ + DBL_EXP_MASK < 0x100000 ? 20 : \ + DBL_EXP_MASK < 0x200000 ? 21 : \ + DBL_EXP_MASK < 0x400000 ? 22 : \ + DBL_EXP_MASK < 0x800000 ? 23 : \ + DBL_EXP_MASK < 0x1000000 ? 24 : \ + DBL_EXP_MASK < 0x2000000 ? 25 : \ + DBL_EXP_MASK < 0x4000000 ? 26 : \ + DBL_EXP_MASK < 0x8000000 ? 27 : \ + DBL_EXP_MASK < 0x10000000 ? 28 : \ + DBL_EXP_MASK < 0x20000000 ? 29 : \ + DBL_EXP_MASK < 0x40000000 ? 30 : \ + DBL_EXP_MASK <= 0x7fffffff ? 31 : \ + 32) +#define LDBL_EXP_BIT \ + (LDBL_EXP_MASK < 0x100 ? 8 : \ + LDBL_EXP_MASK < 0x200 ? 9 : \ + LDBL_EXP_MASK < 0x400 ? 10 : \ + LDBL_EXP_MASK < 0x800 ? 11 : \ + LDBL_EXP_MASK < 0x1000 ? 12 : \ + LDBL_EXP_MASK < 0x2000 ? 13 : \ + LDBL_EXP_MASK < 0x4000 ? 14 : \ + LDBL_EXP_MASK < 0x8000 ? 15 : \ + LDBL_EXP_MASK < 0x10000 ? 16 : \ + LDBL_EXP_MASK < 0x20000 ? 17 : \ + LDBL_EXP_MASK < 0x40000 ? 18 : \ + LDBL_EXP_MASK < 0x80000 ? 19 : \ + LDBL_EXP_MASK < 0x100000 ? 20 : \ + LDBL_EXP_MASK < 0x200000 ? 21 : \ + LDBL_EXP_MASK < 0x400000 ? 22 : \ + LDBL_EXP_MASK < 0x800000 ? 23 : \ + LDBL_EXP_MASK < 0x1000000 ? 24 : \ + LDBL_EXP_MASK < 0x2000000 ? 25 : \ + LDBL_EXP_MASK < 0x4000000 ? 26 : \ + LDBL_EXP_MASK < 0x8000000 ? 27 : \ + LDBL_EXP_MASK < 0x10000000 ? 28 : \ + LDBL_EXP_MASK < 0x20000000 ? 29 : \ + LDBL_EXP_MASK < 0x40000000 ? 30 : \ + LDBL_EXP_MASK <= 0x7fffffff ? 31 : \ + 32) + +/* Number of bits used for a floating-point number: the mantissa (not + counting the "hidden bit", since it may or may not be explicit), the + exponent, and the sign. */ +#define FLT_TOTAL_BIT ((FLT_MANT_BIT - 1) + FLT_EXP_BIT + 1) +#define DBL_TOTAL_BIT ((DBL_MANT_BIT - 1) + DBL_EXP_BIT + 1) +#define LDBL_TOTAL_BIT ((LDBL_MANT_BIT - 1) + LDBL_EXP_BIT + 1) + +/* Number of bytes used for a floating-point number. + This can be smaller than the 'sizeof'. For example, on i386 systems, + 'long double' most often have LDBL_MANT_BIT = 64, LDBL_EXP_BIT = 16, hence + LDBL_TOTAL_BIT = 80 bits, i.e. 10 bytes of consecutive memory, but + sizeof (long double) = 12 or = 16. */ +#define SIZEOF_FLT ((FLT_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT) +#define SIZEOF_DBL ((DBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT) +#define SIZEOF_LDBL ((LDBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT) + +/* Verify that SIZEOF_FLT <= sizeof (float) etc. */ +typedef int verify_sizeof_flt[2 * (SIZEOF_FLT <= sizeof (float)) - 1]; +typedef int verify_sizeof_dbl[2 * (SIZEOF_DBL <= sizeof (double)) - 1]; +typedef int verify_sizeof_ldbl[2 * (SIZEOF_LDBL <= sizeof (long double)) - 1]; + +#endif /* _FLOATPLUS_H */ |