__tanf.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include "libm.h"
/* INDENT OFF */
/*
* float __k_tan(double x);
* kernel (float) tan function on [-pi/4, pi/4], pi/4 ~ 0.785398164
* Input x is in double and assumed to be bounded by ~pi/4 in magnitude.
*
* Constants:
* The hexadecimal values are the intended ones for the following constants.
* The decimal values may be used, provided that the compiler will convert
* from decimal to binary accurately enough to produce the hexadecimal values
* shown.
*/
static const double q[] = {
/* one */ 1.0,
/* P0 */ 4.46066928428959230679140546271810308098793029785e-0003,
/* P1 */ 4.92165316309189027066395283327437937259674072266e+0000,
/* P2 */ -7.11410648161473480044492134766187518835067749023e-0001,
/* P3 */ 4.08549808374053391446523164631798863410949707031e+0000,
/* P4 */ 2.50411070398050927821032018982805311679840087891e+0000,
/* P5 */ 1.11492064560251158411574579076841473579406738281e+0001,
/* P6 */ -1.50565540968422650891511693771462887525558471680e+0000,
/* P7 */ -1.81484378878349295050043110677506774663925170898e+0000,
/* T0 */ 3.333335997532835641297409611782510896641e-0001,
/* T1 */ 2.999997598248363761541668282006867229939e+00,
};
/* INDENT ON */
#define one q[0]
#define P0 q[1]
#define P1 q[2]
#define P2 q[3]
#define P3 q[4]
#define P4 q[5]
#define P5 q[6]
#define P6 q[7]
#define P7 q[8]
#define T0 q[9]
#define T1 q[10]
float
__k_tanf(double x, int n) {
float ft = 0.0;
double z, w;
int ix;
ix = ((int *) &x)[HIWORD] & ~0x80000000; /* ix = leading |x| */
/* small argument */
if (ix < 0x3f800000) { /* if |x| < 0.0078125 = 2**-7 */
if (ix < 0x3f100000) { /* if |x| < 2**-14 */
if ((int) x == 0) { /* raise inexact if x != 0 */
ft = n == 0 ? (float) x : (float) (-one / x);
}
return (ft);
}
z = (x * T0) * (T1 + x * x);
ft = n == 0 ? (float) z : (float) (-one / z);
return (ft);
}
z = x * x;
w = ((P0 * x) * (P1 + z * (P2 + z)) * (P3 + z * (P4 + z)))
* (P5 + z * (P6 + z * (P7 + z)));
ft = n == 0 ? (float) w : (float) (-one / w);
return (ft);
}