1 /* s_tanl.c -- long double version of s_tan.c.
2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
5 /* @(#)s_tan.c 5.1 93/09/24 */
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
14 * ====================================================
18 * Return tangent function of x.
21 * __kernel_tanl ... tangent function on [-pi/4,pi/4]
22 * __ieee754_rem_pio2l ... argument reduction routine
25 * Let S,C and T denote the sin, cos and tan respectively on
26 * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
27 * in [-pi/4 , +pi/4], and let n = k mod 4.
30 * n sin(x) cos(x) tan(x)
31 * ----------------------------------------------------------
36 * ----------------------------------------------------------
39 * Let trig be any of sin, cos, or tan.
40 * trig(+-INF) is NaN, with signals;
41 * trig(NaN) is that NaN;
44 * TRIG(x) returns trig(x) nearly rounded
49 #include "math_private.h"
52 long double __tanl(long double x)
58 long double y[2],z=0.0L;
62 GET_LDOUBLE_MSW64(ix,x);
65 ix &= 0x7fffffffffffffffLL;
66 if(ix <= 0x3ffe921fb54442d1LL) return __kernel_tanl(x,z,1);
68 /* tanl(Inf or NaN) is NaN */
69 else if (ix>=0x7fff000000000000LL) {
70 if (ix == 0x7fff000000000000LL) {
71 GET_LDOUBLE_LSW64(n,x);
78 /* argument reduction needed */
80 n = __ieee754_rem_pio2l(x,y);
81 return __kernel_tanl(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
85 weak_alias (__tanl, tanl)