newlib/libm/mathfp/sf_numtest.c

   1
   2 /* @(#)z_numtestf.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 int
  26 numtestf (float x)
  27 {
  28   __int32_t wx;
  29   int exp;
  30
  31   GET_FLOAT_WORD (wx, x);
  32
  33   exp = (wx & 0x7f800000) >> 23;
  34
  35   /* Check for a zero input. */
  36   if (x == 0.0)
  37     {
  38       return (0);
  39     }
  40
  41   /* Check for not a number or infinity. */
  42   if (exp == 0xff)
  43     {
  44       if(wx & 0x7fffff)
  45         return (NAN);
  46       else
  47         return (INF);
  48     }
  49
  50   /* Otherwise it's a finite value. */
  51   else
  52     return (NUM);
  53 }
  54
  55 #ifdef _DOUBLE_IS_32BITS
  56
  57 int numtest (double x)
  58 {
  59   return numtestf ((float) x);
  60 }
  61
  62 #endif /* defined(_DOUBLE_IS_32BITS) */