+/* Copyright 2001 by Stephen L. Moshier <moshier@na-net.ornl.gov>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Specification. */
+#include <math.h>
+
/* s_atanl.c
*
* Inverse circular tangent for 128-bit long double precision
*
*/
-/* Copyright 2001 by Stephen L. Moshier <moshier@na-net.ornl.gov> */
-
-#include "mathl.h"
-
-#include <math.h>
-
/* arctan(k/8), k = 0, ..., 82 */
static const long double atantbl[84] = {
0.0000000000000000000000000000000000000000E0L,
int k, sign;
long double t, u, p, q;
- sign = (x < 0) ? -1 : 1;
-
/* Check for zero or NaN. */
- if (x != x || x == 0.0)
+ if (isnanl (x) || x == 0.0)
return x + x;
- /* Check for infinity. */
+ sign = x < 0.0;
+
if (x + x == x)
- return sign * atantbl[83];
+ {
+ /* Infinity. */
+ if (sign)
+ return -atantbl[83];
+ else
+ return atantbl[83];
+ }
- x *= sign;
+ if (sign)
+ x = -x;
- if (x >= 10.25) /* 10.25 */
+ if (x >= 10.25)
{
k = 83;
t = -1.0/x;
u = t * u * p / q + t;
/* arctan x = arctan u + arctan t */
- return sign * (atantbl[k] + u);
+ u = atantbl[k] + u;
+ if (sign)
+ return (-u);
+ else
+ return u;
}