source: azure_iot_hub/trunk/musl-1.1.18/src/math/cosl.c@ 389

#include "libm.h"

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

        u.i.se &= 0x7fff;
        if (u.i.se == 0x7fff)
                return x - x;
        x = u.f;
        if (x < M_PI_4) {
                if (u.i.se < 0x3fff - LDBL_MANT_DIG)
                        /* raise inexact if x!=0 */
                        return 1.0 + x;
                return __cosl(x, 0);
        }
        n = __rem_pio2l(x, y);
        hi = y[0];
        lo = y[1];
        switch (n & 3) {
        case 0:
                return __cosl(hi, lo);
        case 1:
                return -__sinl(hi, lo, 1);
        case 2:
                return -__cosl(hi, lo);
        case 3:
        default:
                return __sinl(hi, lo, 1);
        }
}
#endif