forked from KolibriOS/kolibrios
28 lines
790 B
C
28 lines
790 B
C
#include <math.h>
|
|
#include <errno.h>
|
|
#include "fastmath.h"
|
|
|
|
/* acosh(x) = log (x + sqrt(x * x - 1)) */
|
|
long double acoshl (long double x)
|
|
{
|
|
if (isnan (x))
|
|
return x;
|
|
|
|
if (x < 1.0L)
|
|
{
|
|
errno = EDOM;
|
|
return nanl("");
|
|
}
|
|
if (x > 0x1p32L)
|
|
/* Avoid overflow (and unnecessary calculation when
|
|
sqrt (x * x - 1) == x).
|
|
The M_LN2 define doesn't have enough precison for
|
|
long double so use this one. GCC optimizes by replacing
|
|
the const with a fldln2 insn. */
|
|
return __fast_logl (x) + 6.9314718055994530941723E-1L;
|
|
|
|
/* Since x >= 1, the arg to log will always be greater than
|
|
the fyl2xp1 limit (approx 0.29) so just use logl. */
|
|
return __fast_logl (x + __fast_sqrtl((x + 1.0L) * (x - 1.0L)));
|
|
}
|