34  *    threshold is |x| < 0x1pN with N = -(P/2+M).  P is the precision of the
43  * 3. For 1 <= |x| < 0x1p(P-1), argument reduction is required where
45  *    0 <= r < 1.  With the given domain, a simplified inline floor(x)
54  * 4. For |x| >= 0x1p(P-1), |x| is integral and tanpi(x) = copysign(0,x).
58  *    tanpi(+-0) = +-0
59  *    tanpi(n) = +0 for positive even and negative odd integer n.
60  *    tanpi(n) = -0 for positive odd and negative even integer n.
75 pi_hi =  3.1415926814079285e+00,	/* 0x400921fb 0x58000000 */
76 pi_lo = -2.7818135228334233e-08;	/* 0xbe5dde97 0x3dcb3b3a */
108 volatile static const double vzero = 0;
117 	ix = hx & 0x7fffffff;  in tanpi()
120 	if (ix < 0x3ff00000) {			/* |x| < 1 */  in tanpi()
121 		if (ix < 0x3fe00000) {		/* |x| < 0.5 */  in tanpi()
122 			if (ix < 0x3e200000) {	/* |x| < 0x1p-29 */  in tanpi()
123 				if (x == 0)  in tanpi()
130 				INSERT_WORDS(hi, hx, 0);  in tanpi()
131 				hi *= 0x1p53;  in tanpi()
132 				lo = x * 0x1p53 - hi;  in tanpi()
135 				return (t * 0x1p-53);  in tanpi()
142 		return ((hx & 0x80000000) ? -t : t);  in tanpi()
145 	if (ix < 0x43300000) {		/* 1 <= |x| < 0x1p52 */  in tanpi()
151 		if (ix < 0x3fe00000)		/* |x| < 0.5 */  in tanpi()
152 			t = ix == 0 ? copysign(0, odd) : __kernel_tanpi(ax);  in tanpi()
158 		return ((hx & 0x80000000) ? -t : t);  in tanpi()
162 	if (ix >= 0x7ff00000)  in tanpi()
166 	 * For 0x1p52 <= |x| < 0x1p53 need to determine if x is an even  in tanpi()
167 	 * or odd integer to set t = +0 or -0.  in tanpi()
168 	 * For |x| >= 0x1p54, it is always an even integer, so t = 0.  in tanpi()
170 	t = ix >= 0x43400000 ? 0 : (copysign(0, (lx & 1) ? -1 : 1));  in tanpi()
171 	return ((hx & 0x80000000) ? -t : t);  in tanpi()