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82c19bdfe3
Update the power of ten tables used by the common implementation when long double is not the most expressive real type. * stdlib/fpioconst.h: Include bits/floatn.h. (FPIOCONST_HAVE_EXTENDED_RANGE): New macro for testing how big the power of ten table should be. (FPIOCONST_POW10_ARRAY_SIZE): Use larger table if above is true. * stdlib/fpioconst.c (__tens): Use FPIOCONST_HAVE_EXTENDED_RANGE to include larger tables when _Float128 support is enabled. (_fpioconst_pow10): Likewise.
85 lines
3.0 KiB
C
85 lines
3.0 KiB
C
/* Header file for constants used in floating point <-> decimal conversions.
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Copyright (C) 1995-2017 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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<http://www.gnu.org/licenses/>. */
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#ifndef _FPIOCONST_H
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#define _FPIOCONST_H
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#include <float.h>
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#include <math.h>
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#include <gmp.h>
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/* These values are used by __printf_fp, where they are noncritical (if the
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value is not large enough, it will just be slower); and by
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strtof/strtod/strtold, where it is critical (it's used for overflow
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detection).
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XXX These should be defined in <float.h>. For the time being, we have the
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IEEE754 values here. */
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#if !defined __NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ > 1024
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# define LDBL_MAX_10_EXP_LOG 12 /* = floor(log_2(LDBL_MAX_10_EXP)) */
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#else
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# define LDBL_MAX_10_EXP_LOG 8 /* = floor(log_2(LDBL_MAX_10_EXP)) */
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#endif
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#define DBL_MAX_10_EXP_LOG 8 /* = floor(log_2(DBL_MAX_10_EXP)) */
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#define FLT_MAX_10_EXP_LOG 5 /* = floor(log_2(FLT_MAX_10_EXP)) */
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/* On some machines, _Float128 may be ABI-distinct from long double (e.g
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IBM extended precision). */
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#include <bits/floatn.h>
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/* For strtold, we need powers of 10 up to floor (log_2 (LDBL_MANT_DIG
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- LDBL_MIN_EXP + 2)). When _Float128 is enabled in libm and it is
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ABI-distinct from long double (e.g. on powerpc64le), we also need powers
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of 10 up to floor (log_2 (FLT128_MANT_DIG - FLT128_MIN_EXP + 2)). */
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#define FPIOCONST_HAVE_EXTENDED_RANGE \
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((!defined __NO_LONG_DOUBLE_MATH && __LDBL_MAX_EXP__ > 1024) \
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|| __HAVE_DISTINCT_FLOAT128)
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#if FPIOCONST_HAVE_EXTENDED_RANGE
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# define FPIOCONST_POW10_ARRAY_SIZE 15
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#else
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# define FPIOCONST_POW10_ARRAY_SIZE 11
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#endif
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/* The array with the number representation. */
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extern const mp_limb_t __tens[] attribute_hidden;
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/* Table of powers of ten. This is used by __printf_fp and by
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strtof/strtod/strtold. */
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struct mp_power
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{
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size_t arrayoff; /* Offset in `__tens'. */
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mp_size_t arraysize; /* Size of the array. */
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int p_expo; /* Exponent of the number 10^(2^i). */
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int m_expo; /* Exponent of the number 10^-(2^i-1). */
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};
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extern const struct mp_power _fpioconst_pow10[FPIOCONST_POW10_ARRAY_SIZE]
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attribute_hidden;
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/* The constants in the array `_fpioconst_pow10' have an offset. */
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#if BITS_PER_MP_LIMB == 32
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# define _FPIO_CONST_OFFSET 2
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#else
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# define _FPIO_CONST_OFFSET 1
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#endif
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#endif /* fpioconst.h */
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