3 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
4 long double acoshl(long double x)
8 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
9 /* acosh(x) = log(x + sqrt(x*x-1)) */
10 long double acoshl(long double x)
14 struct{uint64_t m; int16_t se; uint16_t pad;} i;
17 if (u.i.se < 0x3fff + 1)
18 /* x < 2, invalid if x < 1 or nan */
19 return log1pl(x-1 + sqrtl((x-1)*(x-1)+2*(x-1)));
20 if (u.i.se < 0x3fff + 32)
22 return logl(2*x - 1/(x+sqrtl(x*x-1)));
23 return logl(x) + 0.693147180559945309417232121458176568L;