source: asp3_tinet_ecnl_arm/trunk/musl-1.1.18/src/math/tanl.c@ 352

#include "libm.h"

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double tanl(long double x)
{
        return tan(x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
long double tanl(long double x)
{
        union ldshape u = {x};
        long double y[2];
        unsigned n;

        u.i.se &= 0x7fff;
        if (u.i.se == 0x7fff)
                return x - x;
        if (u.f < M_PI_4) {
                if (u.i.se < 0x3fff - LDBL_MANT_DIG/2) {
                        /* raise inexact if x!=0 and underflow if subnormal */
                        FORCE_EVAL(u.i.se == 0 ? x*0x1p-120f : x+0x1p120f);
                        return x;
                }
                return __tanl(x, 0, 0);
        }
        n = __rem_pio2l(x, y);
        return __tanl(y[0], y[1], n&1);
}
#endif