/* Test for NaN that does not need libm.
- Copyright (C) 2007 Free Software Foundation, Inc.
+ Copyright (C) 2007-2013 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ 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 2, or (at your option)
- any later version.
+ 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, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
#include <config.h>
+/* Specification. */
+#ifdef USE_LONG_DOUBLE
+/* Specification found in math.h or isnanl-nolibm.h. */
+extern int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST;
+#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 <float.h>
#include <string.h>
# define SIZE SIZEOF_LDBL
# define L_(literal) literal##L
#elif ! defined USE_FLOAT
-# define FUNC rpl_isnan
+# define FUNC rpl_isnand
# define DOUBLE double
# define MAX_EXP DBL_MAX_EXP
# define MIN_EXP DBL_MIN_EXP
((sizeof (DOUBLE) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
typedef union { DOUBLE value; unsigned int word[NWORDS]; } memory_double;
+/* Most hosts nowadays use IEEE floating point, so they use IEC 60559
+ representations, have infinities and NaNs, and do not trap on
+ exceptions. Define IEEE_FLOATING_POINT if this host is one of the
+ typical ones. The C11 macro __STDC_IEC_559__ is close to what is
+ wanted here, but is not quite right because this file does not require
+ all the features of C11 Annex F (and does not require C11 at all,
+ for that matter). */
+
+#define IEEE_FLOATING_POINT (FLT_RADIX == 2 && FLT_MANT_DIG == 24 \
+ && FLT_MIN_EXP == -125 && FLT_MAX_EXP == 128)
+
int
FUNC (DOUBLE x)
{
-#ifdef KNOWN_EXPBIT0_LOCATION
+#if defined KNOWN_EXPBIT0_LOCATION && IEEE_FLOATING_POINT
+# 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_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
+ /* 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
- /* 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. */
+# if defined __SUNPRO_C || defined __ICC || defined _MSC_VER \
+ || defined __DECC || defined __TINYC__ \
+ || (defined __sgi && !defined __GNUC__)
+ /* The Sun C 5.0, Intel ICC 10.0, Microsoft Visual C/C++ 9.0, Compaq (ex-DEC)
+ 6.4, and TinyCC compilers don't recognize the initializers as constant
+ expressions. The Compaq compiler also fails when constant-folding
+ 0.0 / 0.0 even when constant-folding is not required. The Microsoft
+ Visual C/C++ compiler also fails when constant-folding 1.0 / 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);
+ DOUBLE plus_inf = L_(1.0) / zero;
+ DOUBLE minus_inf = -L_(1.0) / zero;
nan.value = zero / zero;
-# else
+# 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
+# endif
{
memory_double m;
-Infinity, which have the same exponent. */
m.value = x;
if (((m.word[EXPBIT0_WORD] ^ nan.word[EXPBIT0_WORD])
- & (EXP_MASK << EXPBIT0_BIT))
- == 0)
+ & (EXP_MASK << EXPBIT0_BIT))
+ == 0)
return (memcmp (&m.value, &plus_inf, SIZE) != 0
- && memcmp (&m.value, &minus_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. */
+ /* The configuration did not find sufficient information, or does
+ not use IEEE floating point. Give up about the signaling NaNs;
+ handle only the quiet NaNs. */
if (x == x)
- return 0;
+ {
+# 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_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
+ /* 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
projects / gnulib.git / blobdiff