newlib/libm/mathfp/s_numtest.c

   1
   2 /* @(#)z_numtest.c 1.0 98/08/13 */
   3 /******************************************************************
   4  * Numtest
   5  *
   6  * Input:
   7  *   x - pointer to a floating point value
   8  *
   9  * Output:
  10  *   An integer that indicates what kind of number was passed in:
  11  *     NUM = 3 - a finite value
  12  *     NAN = 2 - not a number
  13  *     INF = 1 - an infinite value
  14  *           0 - zero
  15  *
  16  * Description:
  17  *   This routine returns an integer that indicates the character-
  18  *   istics of the number that was passed in.
  19  *
  20  *****************************************************************/
  21
  22 #include "fdlibm.h"
  23 #include "zmath.h"
  24
  25 #ifndef _DOUBLE_IS_32BITS
  26
  27 int
  28 numtest (double x)
  29 {
  30   __uint32_t hx, lx;
  31   int exp;
  32
  33   EXTRACT_WORDS (hx, lx, x);
  34
  35   exp = (hx & 0x7ff00000) >> 20;
  36
  37   /* Check for a zero input. */
  38   if (x == 0.0)
  39     {
  40       return (0);
  41     }
  42
  43   /* Check for not a number or infinity. */
  44   if (exp == 0x7ff)
  45     {
  46       if(hx & 0xf0000 || lx)
  47         return (NAN);
  48       else
  49         return (INF);
  50     }
  51
  52   /* Otherwise it's a finite value. */
  53   else
  54     return (NUM);
  55 }
  56
  57 #endif /* _DOUBLE_IS_32BITS */