53 lines
1.9 KiB
C
53 lines
1.9 KiB
C
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/* Macros for the implementation of *cvt functions, double version.
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Copyright (C) 1995-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <float.h>
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#define FLOAT_TYPE double
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#define FUNC_PREFIX
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#define FLOAT_FMT_FLAG
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#define FLOAT_NAME_EXT
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#define FLOAT_MIN_10_EXP DBL_MIN_10_EXP
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/* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we
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don't have log10 available in the preprocessor. */
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#define MAXDIG (NDIGIT_MAX + 3)
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#define FCVT_MAXDIG (DBL_MAX_10_EXP + MAXDIG)
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#if DBL_MANT_DIG == 53
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# define NDIGIT_MAX 17
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#elif DBL_MANT_DIG == 24
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# define NDIGIT_MAX 9
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#elif DBL_MANT_DIG == 56
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# define NDIGIT_MAX 18
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#else
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/* See IEEE 854 5.6, table 2 for this formula. Unfortunately we need a
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compile time constant here, so we cannot use it. */
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# error "NDIGIT_MAX must be precomputed"
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# define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
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#endif
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#if DBL_MIN_10_EXP == -37
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# define FLOAT_MIN_10_NORM 1.0e-37
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#elif DBL_MIN_10_EXP == -307
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# define FLOAT_MIN_10_NORM 1.0e-307
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#elif DBL_MIN_10_EXP == -4931
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# define FLOAT_MIN_10_NORM 1.0e-4931
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#else
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/* libc can't depend on libm. */
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# error "FLOAT_MIN_10_NORM must be precomputed"
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# define FLOAT_MIN_10_NORM exp10 (DBL_MIN_10_EXP)
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#endif
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