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