105 lines
3 KiB
C
105 lines
3 KiB
C
/* Macros for quiet not-a-number.
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Copyright (C) 2007-2025 Free Software Foundation, Inc.
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This file 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
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file 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, see <https://www.gnu.org/licenses/>. */
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#ifndef _GL_NAN_H
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#define _GL_NAN_H
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/* IBM z/OS supports both hexadecimal and IEEE floating-point formats. The
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former does not support NaN and its isnan() implementation returns zero
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for all values. */
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#if defined __MVS__ && defined __IBMC__ && !defined __BFP__
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# error "NaN is not supported with IBM's hexadecimal floating-point format; please re-compile with -qfloat=ieee"
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* NaNf () returns a 'float' not-a-number. */
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/* The Compaq (ex-DEC) C 6.4 compiler and the Microsoft MSVC 9 compiler choke
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on the expression 0.0 / 0.0. The IBM XL C compiler on z/OS complains.
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PGI 16.10 complains. clang 13 on mips64 does incorrect constant-folding. */
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#if (defined __DECC || defined _MSC_VER \
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|| (defined __MVS__ && defined __IBMC__) \
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|| defined __PGI \
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|| defined __mips__)
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static float
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NaNf ()
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{
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static float volatile zero = 0.0f;
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return zero / zero;
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}
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#else
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# define NaNf() (0.0f / 0.0f)
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#endif
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/* NaNd () returns a 'double' not-a-number. */
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/* The Compaq (ex-DEC) C 6.4 compiler and the Microsoft MSVC 9 compiler choke
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on the expression 0.0 / 0.0. The IBM XL C compiler on z/OS complains.
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PGI 16.10 complains. clang 13 on mips64 does incorrect constant-folding. */
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#if (defined __DECC || defined _MSC_VER \
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|| (defined __MVS__ && defined __IBMC__) \
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|| defined __PGI \
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|| defined __mips__)
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static double
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NaNd ()
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{
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static double volatile zero = 0.0;
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return zero / zero;
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}
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#else
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# define NaNd() (0.0 / 0.0)
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#endif
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/* NaNl () returns a 'long double' not-a-number. */
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/* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
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runtime type conversion.
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The Microsoft MSVC 9 compiler chokes on the expression 0.0L / 0.0L.
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The IBM XL C compiler on z/OS complains.
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PGI 16.10 complains.
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Avoid possible incorrect constant-folding on mips. */
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#ifdef __sgi
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static long double NaNl ()
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{
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double zero = 0.0;
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return zero / zero;
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}
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#elif (defined _MSC_VER \
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|| (defined __MVS__ && defined __IBMC__) \
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|| defined __PGI \
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|| defined __mips__)
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static long double
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NaNl ()
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{
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static long double volatile zero = 0.0L;
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return zero / zero;
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}
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#else
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# define NaNl() (0.0L / 0.0L)
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* _GL_NAN_H */
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