1 #include "libm.h" 2 3 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 4 long double acoshl(long double x) 5 { 6 return acosh(x); 7 } 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) 11 { 12 union ldshape u = {x}; 13 int e = u.i.se & 0x7fff; 14 15 if (e < 0x3fff + 1) 16 /* |x| < 2, invalid if x < 1 or nan */ 17 return log1pl(x-1 + sqrtl((x-1)*(x-1)+2*(x-1))); 18 if (e < 0x3fff + 32) 19 /* |x| < 0x1p32 */ 20 return logl(2*x - 1/(x+sqrtl(x*x-1))); 21 return logl(x) + 0.693147180559945309417232121458176568L; 22 } 23 #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 24 // TODO: broken implementation to make things compile 25 long double acoshl(long double x) 26 { 27 return acosh(x); 28 } 29 #endif 30