_C_STD_BEGIN
_CRTIMP2_PURE double __CLRCALL_PURE_OR_CDECL _Cosh(double x, double y)
{ /* compute y * cosh(x), |y| <= 1 */
switch (_Dtest(&x))
{ /* test for special codes */
case _NANCODE:
case _INFCODE:
return (x);
case 0:
return (y);
default: /* finite */
if (y == 0.0)
return (y);
if (x < 0.0)
x = -x;
if (x < _Xbig)
{ /* worth adding in exp(-x) */
_Exp(&x, 1.0, -1);
return (y * (x + 0.25 / x));
}
switch (_Exp(&x, y, -1))
{ /* report over/underflow */
case 0:
_Feraise(_FE_UNDERFLOW);
break;
case _INFCODE:
_Feraise(_FE_OVERFLOW);
}
return (x);
}
}
double (exp)(double x)
{ /* compute exp(x) */
switch (_Dtest(&x))
{ /* test for special codes */
case NAN:
errno = EDOM;
return (x);
case INF:
errno = ERANGE;
return (DSIGN(x) ? 0.0 : _Inf._D);
case 0:
return (1.0);
default: /* finite */
if (0 <= _Exp(&x, 0))
errno = ERANGE;
return (x);
}
}
