59 lines
1.1 KiB
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 */
|