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git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/ieee754/ldbl-128/s_tanl.c
1 /* s_tanl.c -- long double version of s_tan.c.
4 /* @(#)s_tan.c 5.1 93/09/24 */
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
13 * ====================================================
17 * Return tangent function of x.
20 * __kernel_tanl ... tangent function on [-pi/4,pi/4]
21 * __ieee754_rem_pio2l ... argument reduction routine
24 * Let S,C and T denote the sin, cos and tan respectively on
25 * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
26 * in [-pi/4 , +pi/4], and let n = k mod 4.
29 * n sin(x) cos(x) tan(x)
30 * ----------------------------------------------------------
35 * ----------------------------------------------------------
38 * Let trig be any of sin, cos, or tan.
39 * trig(+-INF) is NaN, with signals;
40 * trig(NaN) is that NaN;
43 * TRIG(x) returns trig(x) nearly rounded
48 #include <math_private.h>
49 #include <libm-alias-ldouble.h>
51 _Float128
__tanl(_Float128 x
)
57 GET_LDOUBLE_MSW64(ix
,x
);
60 ix
&= 0x7fffffffffffffffLL
;
61 if(ix
<= 0x3ffe921fb54442d1LL
) return __kernel_tanl(x
,z
,1);
63 /* tanl(Inf or NaN) is NaN */
64 else if (ix
>=0x7fff000000000000LL
) {
65 if (ix
== 0x7fff000000000000LL
) {
66 GET_LDOUBLE_LSW64(n
,x
);
73 /* argument reduction needed */
75 n
= __ieee754_rem_pio2l(x
,y
);
76 return __kernel_tanl(y
[0],y
[1],1-((n
&1)<<1)); /* 1 -- n even
80 libm_alias_ldouble (__tan
, tan
)