ix = __HI(x);
u.d = x; ix = __HI(u);
	double fd_tan(double x)#else	double fd_tan(x)	double x;#endif{	double y[2],z=0.0;	int n, ix;    /* High word of x. */	ix = __HI(x);    /* |x| ~< pi/4 */	ix &= 0x7fffffff;	if(ix <= 0x3fe921fb) return __kernel_tan(x,z,1);    /* tan(Inf or NaN) is NaN */	else if (ix>=0x7ff00000) return x-x;		/* NaN */    /* argument reduction needed */	else {	    n = __ieee754_rem_pio2(x,y);	    return __kernel_tan(y[0],y[1],1-((n&1)<<1)); /*   1 -- n even							-1 -- n odd */	}}