Imported Upstream version 0.9.1upstream/0.9.1

1 files changed, 161 insertions, 0 deletions

diff --git a/lib/isnan.c b/lib/isnan.c
new file mode 100644
index 00000000..f24f5761
--- /dev/null
+++ b/lib/isnan.c
@@ -0,0 +1,161 @@
+/* Test for NaN that does not need libm.
+   Copyright (C) 2007-2008 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser 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>
+
+#include <float.h>
+#include <string.h>
+
+#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
+}