X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=lib%2Fisnan.c;fp=lib%2Fisnan.c;h=e748c1c906fb43c69d90e8ac9fe0cae0789b1f06;hb=c7e61475680fa226bd9b8bdd469cd66914e630f5;hp=0000000000000000000000000000000000000000;hpb=800deb09b422a73c1212233a93839a223ff59678;p=debian%2Fgzip
diff --git a/lib/isnan.c b/lib/isnan.c
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+++ b/lib/isnan.c
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+/* Test for NaN that does not need libm.
+ Copyright (C) 2007-2009 Free Software Foundation, Inc.
+
+ 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 3 of the License, 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, see . */
+
+/* Written by Bruno Haible , 2007. */
+
+#include
+
+/* Specification. */
+#ifdef USE_LONG_DOUBLE
+/* Specification found in math.h or isnanl-nolibm.h. */
+extern int rpl_isnanl (long double x);
+#elif ! defined USE_FLOAT
+/* Specification found in math.h or isnand-nolibm.h. */
+extern int rpl_isnand (double x);
+#else /* defined USE_FLOAT */
+/* Specification found in math.h or isnanf-nolibm.h. */
+extern int rpl_isnanf (float x);
+#endif
+
+#include
+#include
+
+#include "float+.h"
+
+#ifdef USE_LONG_DOUBLE
+# define FUNC rpl_isnanl
+# define DOUBLE long double
+# define MAX_EXP LDBL_MAX_EXP
+# define MIN_EXP LDBL_MIN_EXP
+# if defined LDBL_EXPBIT0_WORD && defined LDBL_EXPBIT0_BIT
+# define KNOWN_EXPBIT0_LOCATION
+# define EXPBIT0_WORD LDBL_EXPBIT0_WORD
+# define EXPBIT0_BIT LDBL_EXPBIT0_BIT
+# endif
+# define SIZE SIZEOF_LDBL
+# define L_(literal) literal##L
+#elif ! defined USE_FLOAT
+# define FUNC rpl_isnand
+# define DOUBLE double
+# define MAX_EXP DBL_MAX_EXP
+# define MIN_EXP DBL_MIN_EXP
+# if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
+# define KNOWN_EXPBIT0_LOCATION
+# define EXPBIT0_WORD DBL_EXPBIT0_WORD
+# define EXPBIT0_BIT DBL_EXPBIT0_BIT
+# endif
+# define SIZE SIZEOF_DBL
+# define L_(literal) literal
+#else /* defined USE_FLOAT */
+# define FUNC rpl_isnanf
+# define DOUBLE float
+# define MAX_EXP FLT_MAX_EXP
+# define MIN_EXP FLT_MIN_EXP
+# if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT
+# define KNOWN_EXPBIT0_LOCATION
+# define EXPBIT0_WORD FLT_EXPBIT0_WORD
+# define EXPBIT0_BIT FLT_EXPBIT0_BIT
+# endif
+# define SIZE SIZEOF_FLT
+# define L_(literal) literal##f
+#endif
+
+#define EXP_MASK ((MAX_EXP - MIN_EXP) | 7)
+
+#define NWORDS \
+ ((sizeof (DOUBLE) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+typedef union { DOUBLE value; unsigned int word[NWORDS]; } memory_double;
+
+int
+FUNC (DOUBLE x)
+{
+#ifdef KNOWN_EXPBIT0_LOCATION
+# if defined USE_LONG_DOUBLE && ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_))
+ /* Special CPU dependent code is needed to treat bit patterns outside the
+ IEEE 754 specification (such as Pseudo-NaNs, Pseudo-Infinities,
+ Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals) as NaNs.
+ These bit patterns are:
+ - exponent = 0x0001..0x7FFF, mantissa bit 63 = 0,
+ - exponent = 0x0000, mantissa bit 63 = 1.
+ The NaN bit pattern is:
+ - exponent = 0x7FFF, mantissa >= 0x8000000000000001. */
+ memory_double m;
+ unsigned int exponent;
+
+ m.value = x;
+ exponent = (m.word[EXPBIT0_WORD] >> EXPBIT0_BIT) & EXP_MASK;
+# ifdef WORDS_BIGENDIAN
+ /* Big endian: EXPBIT0_WORD = 0, EXPBIT0_BIT = 16. */
+ if (exponent == 0)
+ return 1 & (m.word[0] >> 15);
+ else if (exponent == EXP_MASK)
+ return (((m.word[0] ^ 0x8000U) << 16) | m.word[1] | (m.word[2] >> 16)) != 0;
+ else
+ return 1 & ~(m.word[0] >> 15);
+# else
+ /* Little endian: EXPBIT0_WORD = 2, EXPBIT0_BIT = 0. */
+ if (exponent == 0)
+ return (m.word[1] >> 31);
+ else if (exponent == EXP_MASK)
+ return ((m.word[1] ^ 0x80000000U) | m.word[0]) != 0;
+ else
+ return (m.word[1] >> 31) ^ 1;
+# endif
+# else
+ /* Be careful to not do any floating-point operation on x, such as x == x,
+ because x may be a signaling NaN. */
+# if defined __SUNPRO_C || defined __DECC || (defined __sgi && !defined __GNUC__)
+ /* The Sun C 5.0 compilers and the Compaq (ex-DEC) 6.4 compilers don't
+ recognize the initializers as constant expressions. The latter compiler
+ also fails when constant-folding 0.0 / 0.0 even when constant-folding is
+ not required. The SGI MIPSpro C compiler complains about "floating-point
+ operation result is out of range". */
+ static DOUBLE zero = L_(0.0);
+ memory_double nan;
+ DOUBLE plus_inf = L_(1.0) / L_(0.0);
+ DOUBLE minus_inf = -L_(1.0) / L_(0.0);
+ nan.value = zero / zero;
+# else
+ static memory_double nan = { L_(0.0) / L_(0.0) };
+ static DOUBLE plus_inf = L_(1.0) / L_(0.0);
+ static DOUBLE minus_inf = -L_(1.0) / L_(0.0);
+# endif
+ {
+ memory_double m;
+
+ /* A NaN can be recognized through its exponent. But exclude +Infinity and
+ -Infinity, which have the same exponent. */
+ m.value = x;
+ if (((m.word[EXPBIT0_WORD] ^ nan.word[EXPBIT0_WORD])
+ & (EXP_MASK << EXPBIT0_BIT))
+ == 0)
+ return (memcmp (&m.value, &plus_inf, SIZE) != 0
+ && memcmp (&m.value, &minus_inf, SIZE) != 0);
+ else
+ return 0;
+ }
+# endif
+#else
+ /* The configuration did not find sufficient information. Give up about
+ the signaling NaNs, handle only the quiet NaNs. */
+ if (x == x)
+ {
+# if defined USE_LONG_DOUBLE && ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_))
+ /* Detect any special bit patterns that pass ==; see comment above. */
+ memory_double m1;
+ memory_double m2;
+
+ memset (&m1.value, 0, SIZE);
+ memset (&m2.value, 0, SIZE);
+ m1.value = x;
+ m2.value = x + (x ? 0.0L : -0.0L);
+ if (memcmp (&m1.value, &m2.value, SIZE) != 0)
+ return 1;
+# endif
+ return 0;
+ }
+ else
+ return 1;
+#endif
+}