third_party/ulib/musl/src/math/coshl.c

#include "libm.h"

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double coshl(long double x) {
    return cosh(x);
}
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
long double coshl(long double x) {
    union ldshape u = {x};
    unsigned ex = u.i.se & 0x7fff;
    uint32_t w;
    long double t;

    /* |x| */
    u.i.se = ex;
    x = u.f;
    w = u.i.m >> 32;

    /* |x| < log(2) */
    if (ex < 0x3fff - 1 || (ex == 0x3fff - 1 && w < 0xb17217f7)) {
        if (ex < 0x3fff - 32) {
            FORCE_EVAL(x + 0x1p120f);
            return 1;
        }
        t = expm1l(x);
        return 1 + t * t / (2 * (1 + t));
    }

    /* |x| < log(LDBL_MAX) */
    if (ex < 0x3fff + 13 || (ex == 0x3fff + 13 && w < 0xb17217f7)) {
        t = expl(x);
        return 0.5 * (t + 1 / t);
    }

    /* |x| > log(LDBL_MAX) or nan */
    t = expl(0.5 * x);
    return 0.5 * t * t;
}
#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
// TODO: broken implementation to make things compile
long double coshl(long double x) {
    return cosh(x);
}
#endif