#include "libm.h"

#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double acoshl(long double x) {
  return acosh(x);
}
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
/* acosh(x) = log(x + sqrt(x*x-1)) */
long double acoshl(long double x) {
  union ldshape u = {x};
  int e = u.i.se & 0x7fff;

  if (e < 0x3fff + 1)
    /* |x| < 2, invalid if x < 1 or nan */
    return log1pl(x - 1 + sqrtl((x - 1) * (x - 1) + 2 * (x - 1)));
  if (e < 0x3fff + 32)
    /* |x| < 0x1p32 */
    return logl(2 * x - 1 / (x + sqrtl(x * x - 1)));
  return logl(x) + 0.693147180559945309417232121458176568L;
}
#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
// TODO: broken implementation to make things compile
long double acoshl(long double x) {
  return acosh(x);
}
#endif