tests/test-ldexpl.c

   1 /* Test of multiplying a 'long double' by a power of 2.
   2    Copyright (C) 2007-2011 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 <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
  18
  19 #include <config.h>
  20
  21 #include <math.h>
  22
  23 #include "signature.h"
  24 SIGNATURE_CHECK (ldexpl, long double, (long double, int));
  25
  26 #include <float.h>
  27
  28 #include "fpucw.h"
  29 #include "isnanl-nolibm.h"
  30 #include "minus-zero.h"
  31 #include "nan.h"
  32 #include "macros.h"
  33
  34 int
  35 main ()
  36 {
  37   int i;
  38   long double x;
  39   long double y;
  40   DECL_LONG_DOUBLE_ROUNDING
  41
  42   BEGIN_LONG_DOUBLE_ROUNDING ();
  43
  44   { /* NaN.  */
  45     x = NaNl ();
  46     y = ldexpl (x, 0); ASSERT (isnanl (y));
  47     y = ldexpl (x, 5); ASSERT (isnanl (y));
  48     y = ldexpl (x, -5); ASSERT (isnanl (y));
  49   }
  50
  51   { /* Positive infinity.  */
  52     x = 1.0L / 0.0L;
  53     y = ldexpl (x, 0); ASSERT (y == x);
  54     y = ldexpl (x, 5); ASSERT (y == x);
  55     y = ldexpl (x, -5); ASSERT (y == x);
  56   }
  57
  58   { /* Negative infinity.  */
  59     x = -1.0L / 0.0L;
  60     y = ldexpl (x, 0); ASSERT (y == x);
  61     y = ldexpl (x, 5); ASSERT (y == x);
  62     y = ldexpl (x, -5); ASSERT (y == x);
  63   }
  64
  65   { /* Positive zero.  */
  66     x = 0.0L;
  67     y = ldexpl (x, 0); ASSERT (y == x); ASSERT (!signbit (x));
  68     y = ldexpl (x, 5); ASSERT (y == x); ASSERT (!signbit (x));
  69     y = ldexpl (x, -5); ASSERT (y == x); ASSERT (!signbit (x));
  70   }
  71
  72   { /* Negative zero.  */
  73     x = minus_zerol;
  74     y = ldexpl (x, 0); ASSERT (y == x); ASSERT (signbit (x));
  75     y = ldexpl (x, 5); ASSERT (y == x); ASSERT (signbit (x));
  76     y = ldexpl (x, -5); ASSERT (y == x); ASSERT (signbit (x));
  77   }
  78
  79   { /* Positive finite number.  */
  80     x = 1.73205L;
  81     y = ldexpl (x, 0); ASSERT (y == x);
  82     y = ldexpl (x, 5); ASSERT (y == x * 32.0L);
  83     y = ldexpl (x, -5); ASSERT (y == x * 0.03125L);
  84   }
  85
  86   { /* Negative finite number.  */
  87     x = -20.085536923187667742L;
  88     y = ldexpl (x, 0); ASSERT (y == x);
  89     y = ldexpl (x, 5); ASSERT (y == x * 32.0L);
  90     y = ldexpl (x, -5); ASSERT (y == x * 0.03125L);
  91   }
  92
  93   for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
  94     {
  95       y = ldexpl (x, 0); ASSERT (y == x);
  96       y = ldexpl (x, 5); ASSERT (y == x * 32.0L);
  97       y = ldexpl (x, -5); ASSERT (y == x * 0.03125L);
  98     }
  99   for (i = 1, x = 1.73205L; i >= LDBL_MIN_EXP; i--, x *= 0.5L)
 100     {
 101       y = ldexpl (x, 0); ASSERT (y == x);
 102       y = ldexpl (x, 5); ASSERT (y == x * 32.0L);
 103       if (i - 5 >= LDBL_MIN_EXP)
 104         {
 105           y = ldexpl (x, -5); ASSERT (y == x * 0.03125L);
 106         }
 107     }
 108   for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
 109     {
 110       y = ldexpl (x, 0); ASSERT (y == x);
 111       y = ldexpl (x, 5); ASSERT (y == x * 32.0L);
 112     }
 113
 114   return 0;
 115 }