66 lines
1.2 KiB
C
66 lines
1.2 KiB
C
|
/* _FSinh function */
|
||
|
|
#include "wctype.h"
|
||
|
|
#include "xmath.h"
|
||
|
|
_STD_BEGIN
|
||
|
|
|
||
|
|
/* coefficients */
|
||
|
|
#define NP (sizeof (p) / sizeof (p[0]) - 1)
|
||
|
|
static const float p[] = { /* courtesy Dr. Tim Prince */
|
||
|
|
0.00020400F,
|
||
|
|
0.00832983F,
|
||
|
|
0.16666737F,
|
||
|
|
0.99999998F};
|
||
|
|
|
||
|
|
_CRTIMP2 float __cdecl _FSinh(float x, float y)
|
||
|
|
{ /* compute y*sinh(x), |y| <= 1 */
|
||
|
|
switch (_FDtest(&x))
|
||
|
|
{ /* test for special codes */
|
||
|
|
case NAN:
|
||
|
|
errno = EDOM;
|
||
|
|
return (x);
|
||
|
|
case INF:
|
||
|
|
if (y == 0)
|
||
|
|
return (0);
|
||
|
|
errno = ERANGE;
|
||
|
|
return (FSIGN(x) ? -_FInf._F : _FInf._F);
|
||
|
|
case 0:
|
||
|
|
return (0);
|
||
|
|
default: /* finite */
|
||
|
|
{ /* compute sinh(finite) */
|
||
|
|
short neg;
|
||
|
|
|
||
|
|
if (x < 0)
|
||
|
|
x = -x, neg = 1;
|
||
|
|
else
|
||
|
|
neg = 0;
|
||
|
|
if (x < _FRteps._F)
|
||
|
|
x *= y; /* x tiny */
|
||
|
|
else if (x < 1)
|
||
|
|
{
|
||
|
|
float w = x * x;
|
||
|
|
|
||
|
|
x += ((p[0] * w + p[1]) * w + p[2]) * w * x;
|
||
|
|
x *= y;
|
||
|
|
}
|
||
|
|
else if (x < _FXbig)
|
||
|
|
{ /* worth adding in exp(-x) */
|
||
|
|
_FExp(&x, 1, -1);
|
||
|
|
x = y * (x - 0.25 / x);
|
||
|
|
}
|
||
|
|
else if (0 <= _FExp(&x, y, -1))
|
||
|
|
errno = ERANGE; /* x large */
|
||
|
|
return (neg ? -x : x);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
_STD_END
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Copyright (c) 1994 by P.J. Plauger. ALL RIGHTS RESERVED.
|
||
|
|
* Consult your license regarding permissions and restrictions.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
941029 pjp: added _STD machinery
|
||
|
|
*/
|