newlib-cygwin/newlib/libm/mathfp/s_numtest.c

59 lines
1.1 KiB
C

/* @(#)z_numtest.c 1.0 98/08/13 */
/******************************************************************
* Numtest
*
* Input:
* x - pointer to a floating point value
*
* Output:
* An integer that indicates what kind of number was passed in:
* NUM = 3 - a finite value
* NAN = 2 - not a number
* INF = 1 - an infinite value
* 0 - zero
*
* Description:
* This routine returns an integer that indicates the character-
* istics of the number that was passed in.
*
*****************************************************************/
#include "fdlibm.h"
#include "zmath.h"
#ifndef _DOUBLE_IS_32BITS
int
_DEFUN (numtest, (double),
double x)
{
__uint32_t hx, lx;
int exp;
EXTRACT_WORDS (hx, lx, x);
exp = (hx & 0x7ff00000) >> 20;
/* Check for a zero input. */
if (x == 0.0)
{
return (0);
}
/* Check for not a number or infinity. */
if (exp == 0x7ff)
{
if(hx & 0xf0000 || lx)
return (NAN);
else
return (INF);
}
/* Otherwise it's a finite value. */
else
return (NUM);
}
#endif /* _DOUBLE_IS_32BITS */