144 строки
5.5 KiB
C
144 строки
5.5 KiB
C
/* Supplemental information about the floating-point formats.
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Copyright (C) 2007, 2009, 2010 Free Software Foundation, Inc.
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Written by Bruno Haible <bruno@clisp.org>, 2007.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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#include <float.h>
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#include <limits.h>
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/* Number of bits in the mantissa of a floating-point number, including the
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"hidden bit". */
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#if FLT_RADIX == 2
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# define FLT_MANT_BIT FLT_MANT_DIG
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# define DBL_MANT_BIT DBL_MANT_DIG
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# define LDBL_MANT_BIT LDBL_MANT_DIG
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#elif FLT_RADIX == 4
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# define FLT_MANT_BIT (FLT_MANT_DIG * 2)
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# define DBL_MANT_BIT (DBL_MANT_DIG * 2)
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# define LDBL_MANT_BIT (LDBL_MANT_DIG * 2)
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#elif FLT_RADIX == 16
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# define FLT_MANT_BIT (FLT_MANT_DIG * 4)
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# define DBL_MANT_BIT (DBL_MANT_DIG * 4)
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# define LDBL_MANT_BIT (LDBL_MANT_DIG * 4)
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#endif
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/* Bit mask that can be used to mask the exponent, as an unsigned number. */
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#define FLT_EXP_MASK ((FLT_MAX_EXP - FLT_MIN_EXP) | 7)
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#define DBL_EXP_MASK ((DBL_MAX_EXP - DBL_MIN_EXP) | 7)
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#define LDBL_EXP_MASK ((LDBL_MAX_EXP - LDBL_MIN_EXP) | 7)
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/* Number of bits used for the exponent of a floating-point number, including
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the exponent's sign. */
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#define FLT_EXP_BIT \
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(FLT_EXP_MASK < 0x100 ? 8 : \
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FLT_EXP_MASK < 0x200 ? 9 : \
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FLT_EXP_MASK < 0x400 ? 10 : \
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FLT_EXP_MASK < 0x800 ? 11 : \
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FLT_EXP_MASK < 0x1000 ? 12 : \
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FLT_EXP_MASK < 0x2000 ? 13 : \
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FLT_EXP_MASK < 0x4000 ? 14 : \
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FLT_EXP_MASK < 0x8000 ? 15 : \
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FLT_EXP_MASK < 0x10000 ? 16 : \
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FLT_EXP_MASK < 0x20000 ? 17 : \
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FLT_EXP_MASK < 0x40000 ? 18 : \
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FLT_EXP_MASK < 0x80000 ? 19 : \
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FLT_EXP_MASK < 0x100000 ? 20 : \
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FLT_EXP_MASK < 0x200000 ? 21 : \
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FLT_EXP_MASK < 0x400000 ? 22 : \
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FLT_EXP_MASK < 0x800000 ? 23 : \
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FLT_EXP_MASK < 0x1000000 ? 24 : \
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FLT_EXP_MASK < 0x2000000 ? 25 : \
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FLT_EXP_MASK < 0x4000000 ? 26 : \
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FLT_EXP_MASK < 0x8000000 ? 27 : \
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FLT_EXP_MASK < 0x10000000 ? 28 : \
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FLT_EXP_MASK < 0x20000000 ? 29 : \
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FLT_EXP_MASK < 0x40000000 ? 30 : \
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FLT_EXP_MASK <= 0x7fffffff ? 31 : \
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32)
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#define DBL_EXP_BIT \
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(DBL_EXP_MASK < 0x100 ? 8 : \
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DBL_EXP_MASK < 0x200 ? 9 : \
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DBL_EXP_MASK < 0x400 ? 10 : \
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DBL_EXP_MASK < 0x800 ? 11 : \
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DBL_EXP_MASK < 0x1000 ? 12 : \
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DBL_EXP_MASK < 0x2000 ? 13 : \
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DBL_EXP_MASK < 0x4000 ? 14 : \
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DBL_EXP_MASK < 0x8000 ? 15 : \
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DBL_EXP_MASK < 0x10000 ? 16 : \
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DBL_EXP_MASK < 0x20000 ? 17 : \
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DBL_EXP_MASK < 0x40000 ? 18 : \
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DBL_EXP_MASK < 0x80000 ? 19 : \
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DBL_EXP_MASK < 0x100000 ? 20 : \
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DBL_EXP_MASK < 0x200000 ? 21 : \
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DBL_EXP_MASK < 0x400000 ? 22 : \
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DBL_EXP_MASK < 0x800000 ? 23 : \
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DBL_EXP_MASK < 0x1000000 ? 24 : \
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DBL_EXP_MASK < 0x2000000 ? 25 : \
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DBL_EXP_MASK < 0x4000000 ? 26 : \
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DBL_EXP_MASK < 0x8000000 ? 27 : \
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DBL_EXP_MASK < 0x10000000 ? 28 : \
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DBL_EXP_MASK < 0x20000000 ? 29 : \
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DBL_EXP_MASK < 0x40000000 ? 30 : \
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DBL_EXP_MASK <= 0x7fffffff ? 31 : \
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32)
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#define LDBL_EXP_BIT \
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(LDBL_EXP_MASK < 0x100 ? 8 : \
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LDBL_EXP_MASK < 0x200 ? 9 : \
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LDBL_EXP_MASK < 0x400 ? 10 : \
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LDBL_EXP_MASK < 0x800 ? 11 : \
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LDBL_EXP_MASK < 0x1000 ? 12 : \
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LDBL_EXP_MASK < 0x2000 ? 13 : \
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LDBL_EXP_MASK < 0x4000 ? 14 : \
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LDBL_EXP_MASK < 0x8000 ? 15 : \
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LDBL_EXP_MASK < 0x10000 ? 16 : \
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LDBL_EXP_MASK < 0x20000 ? 17 : \
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LDBL_EXP_MASK < 0x40000 ? 18 : \
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LDBL_EXP_MASK < 0x80000 ? 19 : \
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LDBL_EXP_MASK < 0x100000 ? 20 : \
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LDBL_EXP_MASK < 0x200000 ? 21 : \
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LDBL_EXP_MASK < 0x400000 ? 22 : \
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LDBL_EXP_MASK < 0x800000 ? 23 : \
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LDBL_EXP_MASK < 0x1000000 ? 24 : \
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LDBL_EXP_MASK < 0x2000000 ? 25 : \
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LDBL_EXP_MASK < 0x4000000 ? 26 : \
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LDBL_EXP_MASK < 0x8000000 ? 27 : \
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LDBL_EXP_MASK < 0x10000000 ? 28 : \
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LDBL_EXP_MASK < 0x20000000 ? 29 : \
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LDBL_EXP_MASK < 0x40000000 ? 30 : \
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LDBL_EXP_MASK <= 0x7fffffff ? 31 : \
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32)
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/* Number of bits used for a floating-point number: the mantissa (not
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counting the "hidden bit", since it may or may not be explicit), the
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exponent, and the sign. */
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#define FLT_TOTAL_BIT ((FLT_MANT_BIT - 1) + FLT_EXP_BIT + 1)
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#define DBL_TOTAL_BIT ((DBL_MANT_BIT - 1) + DBL_EXP_BIT + 1)
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#define LDBL_TOTAL_BIT ((LDBL_MANT_BIT - 1) + LDBL_EXP_BIT + 1)
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/* Number of bytes used for a floating-point number.
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This can be smaller than the 'sizeof'. For example, on i386 systems,
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'long double' most often have LDBL_MANT_BIT = 64, LDBL_EXP_BIT = 16, hence
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LDBL_TOTAL_BIT = 80 bits, i.e. 10 bytes of consecutive memory, but
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sizeof (long double) = 12 or = 16. */
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#define SIZEOF_FLT ((FLT_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
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#define SIZEOF_DBL ((DBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
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#define SIZEOF_LDBL ((LDBL_TOTAL_BIT + CHAR_BIT - 1) / CHAR_BIT)
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/* Verify that SIZEOF_FLT <= sizeof (float) etc. */
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typedef int verify_sizeof_flt[2 * (SIZEOF_FLT <= sizeof (float)) - 1];
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typedef int verify_sizeof_dbl[2 * (SIZEOF_DBL <= sizeof (double)) - 1];
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typedef int verify_sizeof_ldbl[2 * (SIZEOF_LDBL <= sizeof (long double)) - 1];
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