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Member "gnuastro-0.8/bootstrapped/tests/isnan.c" (28 Dec 2018, 7046 Bytes) of package /linux/privat/gnuastro-0.8.tar.lz:


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    1 /* Test for NaN that does not need libm.
    2    Copyright (C) 2007-2018 Free Software Foundation, Inc.
    3 
    4    This program is free software: you can redistribute it and/or modify
    5    it under the terms of the GNU General Public License as published by
    6    the Free Software Foundation; either version 3 of the License, or
    7    (at your option) any later version.
    8 
    9    This program is distributed in the hope that it will be useful,
   10    but WITHOUT ANY WARRANTY; without even the implied warranty of
   11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   12    GNU General Public License for more details.
   13 
   14    You should have received a copy of the GNU General Public License
   15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
   16 
   17 /* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
   18 
   19 #include <config.h>
   20 
   21 /* Specification.  */
   22 #ifdef USE_LONG_DOUBLE
   23 /* Specification found in math.h or isnanl-nolibm.h.  */
   24 extern int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST;
   25 #elif ! defined USE_FLOAT
   26 /* Specification found in math.h or isnand-nolibm.h.  */
   27 extern int rpl_isnand (double x);
   28 #else /* defined USE_FLOAT */
   29 /* Specification found in math.h or isnanf-nolibm.h.  */
   30 extern int rpl_isnanf (float x);
   31 #endif
   32 
   33 #include <float.h>
   34 #include <string.h>
   35 
   36 #include "float+.h"
   37 
   38 #ifdef USE_LONG_DOUBLE
   39 # define FUNC rpl_isnanl
   40 # define DOUBLE long double
   41 # define MAX_EXP LDBL_MAX_EXP
   42 # define MIN_EXP LDBL_MIN_EXP
   43 # if defined LDBL_EXPBIT0_WORD && defined LDBL_EXPBIT0_BIT
   44 #  define KNOWN_EXPBIT0_LOCATION
   45 #  define EXPBIT0_WORD LDBL_EXPBIT0_WORD
   46 #  define EXPBIT0_BIT LDBL_EXPBIT0_BIT
   47 # endif
   48 # define SIZE SIZEOF_LDBL
   49 # define L_(literal) literal##L
   50 #elif ! defined USE_FLOAT
   51 # define FUNC rpl_isnand
   52 # define DOUBLE double
   53 # define MAX_EXP DBL_MAX_EXP
   54 # define MIN_EXP DBL_MIN_EXP
   55 # if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
   56 #  define KNOWN_EXPBIT0_LOCATION
   57 #  define EXPBIT0_WORD DBL_EXPBIT0_WORD
   58 #  define EXPBIT0_BIT DBL_EXPBIT0_BIT
   59 # endif
   60 # define SIZE SIZEOF_DBL
   61 # define L_(literal) literal
   62 #else /* defined USE_FLOAT */
   63 # define FUNC rpl_isnanf
   64 # define DOUBLE float
   65 # define MAX_EXP FLT_MAX_EXP
   66 # define MIN_EXP FLT_MIN_EXP
   67 # if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT
   68 #  define KNOWN_EXPBIT0_LOCATION
   69 #  define EXPBIT0_WORD FLT_EXPBIT0_WORD
   70 #  define EXPBIT0_BIT FLT_EXPBIT0_BIT
   71 # endif
   72 # define SIZE SIZEOF_FLT
   73 # define L_(literal) literal##f
   74 #endif
   75 
   76 #define EXP_MASK ((MAX_EXP - MIN_EXP) | 7)
   77 
   78 #define NWORDS \
   79   ((sizeof (DOUBLE) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
   80 typedef union { DOUBLE value; unsigned int word[NWORDS]; } memory_double;
   81 
   82 /* Most hosts nowadays use IEEE floating point, so they use IEC 60559
   83    representations, have infinities and NaNs, and do not trap on
   84    exceptions.  Define IEEE_FLOATING_POINT if this host is one of the
   85    typical ones.  The C11 macro __STDC_IEC_559__ is close to what is
   86    wanted here, but is not quite right because this file does not require
   87    all the features of C11 Annex F (and does not require C11 at all,
   88    for that matter).  */
   89 
   90 #define IEEE_FLOATING_POINT (FLT_RADIX == 2 && FLT_MANT_DIG == 24 \
   91                              && FLT_MIN_EXP == -125 && FLT_MAX_EXP == 128)
   92 
   93 int
   94 FUNC (DOUBLE x)
   95 {
   96 #if defined KNOWN_EXPBIT0_LOCATION && IEEE_FLOATING_POINT
   97 # 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
   98   /* Special CPU dependent code is needed to treat bit patterns outside the
   99      IEEE 754 specification (such as Pseudo-NaNs, Pseudo-Infinities,
  100      Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals) as NaNs.
  101      These bit patterns are:
  102        - exponent = 0x0001..0x7FFF, mantissa bit 63 = 0,
  103        - exponent = 0x0000, mantissa bit 63 = 1.
  104      The NaN bit pattern is:
  105        - exponent = 0x7FFF, mantissa >= 0x8000000000000001.  */
  106   memory_double m;
  107   unsigned int exponent;
  108 
  109   m.value = x;
  110   exponent = (m.word[EXPBIT0_WORD] >> EXPBIT0_BIT) & EXP_MASK;
  111 #  ifdef WORDS_BIGENDIAN
  112   /* Big endian: EXPBIT0_WORD = 0, EXPBIT0_BIT = 16.  */
  113   if (exponent == 0)
  114     return 1 & (m.word[0] >> 15);
  115   else if (exponent == EXP_MASK)
  116     return (((m.word[0] ^ 0x8000U) << 16) | m.word[1] | (m.word[2] >> 16)) != 0;
  117   else
  118     return 1 & ~(m.word[0] >> 15);
  119 #  else
  120   /* Little endian: EXPBIT0_WORD = 2, EXPBIT0_BIT = 0.  */
  121   if (exponent == 0)
  122     return (m.word[1] >> 31);
  123   else if (exponent == EXP_MASK)
  124     return ((m.word[1] ^ 0x80000000U) | m.word[0]) != 0;
  125   else
  126     return (m.word[1] >> 31) ^ 1;
  127 #  endif
  128 # else
  129   /* Be careful to not do any floating-point operation on x, such as x == x,
  130      because x may be a signaling NaN.  */
  131 #  if defined __SUNPRO_C || defined __ICC || defined _MSC_VER \
  132       || defined __DECC || defined __TINYC__ \
  133       || (defined __sgi && !defined __GNUC__)
  134   /* The Sun C 5.0, Intel ICC 10.0, Microsoft Visual C/C++ 9.0, Compaq (ex-DEC)
  135      6.4, and TinyCC compilers don't recognize the initializers as constant
  136      expressions.  The Compaq compiler also fails when constant-folding
  137      0.0 / 0.0 even when constant-folding is not required.  The Microsoft
  138      Visual C/C++ compiler also fails when constant-folding 1.0 / 0.0 even
  139      when constant-folding is not required. The SGI MIPSpro C compiler
  140      complains about "floating-point operation result is out of range".  */
  141   static DOUBLE zero = L_(0.0);
  142   memory_double nan;
  143   DOUBLE plus_inf = L_(1.0) / zero;
  144   DOUBLE minus_inf = -L_(1.0) / zero;
  145   nan.value = zero / zero;
  146 #  else
  147   static memory_double nan = { L_(0.0) / L_(0.0) };
  148   static DOUBLE plus_inf = L_(1.0) / L_(0.0);
  149   static DOUBLE minus_inf = -L_(1.0) / L_(0.0);
  150 #  endif
  151   {
  152     memory_double m;
  153 
  154     /* A NaN can be recognized through its exponent.  But exclude +Infinity and
  155        -Infinity, which have the same exponent.  */
  156     m.value = x;
  157     if (((m.word[EXPBIT0_WORD] ^ nan.word[EXPBIT0_WORD])
  158          & (EXP_MASK << EXPBIT0_BIT))
  159         == 0)
  160       return (memcmp (&m.value, &plus_inf, SIZE) != 0
  161               && memcmp (&m.value, &minus_inf, SIZE) != 0);
  162     else
  163       return 0;
  164   }
  165 # endif
  166 #else
  167   /* The configuration did not find sufficient information, or does
  168      not use IEEE floating point.  Give up about the signaling NaNs;
  169      handle only the quiet NaNs.  */
  170   if (x == x)
  171     {
  172 # 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
  173       /* Detect any special bit patterns that pass ==; see comment above.  */
  174       memory_double m1;
  175       memory_double m2;
  176 
  177       memset (&m1.value, 0, SIZE);
  178       memset (&m2.value, 0, SIZE);
  179       m1.value = x;
  180       m2.value = x + (x ? 0.0L : -0.0L);
  181       if (memcmp (&m1.value, &m2.value, SIZE) != 0)
  182         return 1;
  183 # endif
  184       return 0;
  185     }
  186   else
  187     return 1;
  188 #endif
  189 }