125c28e83SPiotr Jasiukajtis /* 225c28e83SPiotr Jasiukajtis * CDDL HEADER START 325c28e83SPiotr Jasiukajtis * 425c28e83SPiotr Jasiukajtis * The contents of this file are subject to the terms of the 525c28e83SPiotr Jasiukajtis * Common Development and Distribution License (the "License"). 625c28e83SPiotr Jasiukajtis * You may not use this file except in compliance with the License. 725c28e83SPiotr Jasiukajtis * 825c28e83SPiotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 925c28e83SPiotr Jasiukajtis * or http://www.opensolaris.org/os/licensing. 1025c28e83SPiotr Jasiukajtis * See the License for the specific language governing permissions 1125c28e83SPiotr Jasiukajtis * and limitations under the License. 1225c28e83SPiotr Jasiukajtis * 1325c28e83SPiotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each 1425c28e83SPiotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 1525c28e83SPiotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the 1625c28e83SPiotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying 1725c28e83SPiotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner] 1825c28e83SPiotr Jasiukajtis * 1925c28e83SPiotr Jasiukajtis * CDDL HEADER END 2025c28e83SPiotr Jasiukajtis */ 2125c28e83SPiotr Jasiukajtis 2225c28e83SPiotr Jasiukajtis /* 2325c28e83SPiotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 2425c28e83SPiotr Jasiukajtis */ 2525c28e83SPiotr Jasiukajtis /* 2625c28e83SPiotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 2725c28e83SPiotr Jasiukajtis * Use is subject to license terms. 2825c28e83SPiotr Jasiukajtis */ 2925c28e83SPiotr Jasiukajtis 30*ddc0e0b5SRichard Lowe #pragma weak __tan = tan 3125c28e83SPiotr Jasiukajtis 3225c28e83SPiotr Jasiukajtis /* INDENT OFF */ 3325c28e83SPiotr Jasiukajtis /* 3425c28e83SPiotr Jasiukajtis * tan(x) 3525c28e83SPiotr Jasiukajtis * Table look-up algorithm by K.C. Ng, November, 1989. 3625c28e83SPiotr Jasiukajtis * 3725c28e83SPiotr Jasiukajtis * kernel function: 3825c28e83SPiotr Jasiukajtis * __k_tan ... tangent function on [-pi/4,pi/4] 3925c28e83SPiotr Jasiukajtis * __rem_pio2 ... argument reduction routine 4025c28e83SPiotr Jasiukajtis */ 4125c28e83SPiotr Jasiukajtis /* INDENT ON */ 4225c28e83SPiotr Jasiukajtis 4325c28e83SPiotr Jasiukajtis #include "libm.h" 4425c28e83SPiotr Jasiukajtis #include "libm_protos.h" 4525c28e83SPiotr Jasiukajtis #include <math.h> 4625c28e83SPiotr Jasiukajtis 4725c28e83SPiotr Jasiukajtis double 4825c28e83SPiotr Jasiukajtis tan(double x) { 4925c28e83SPiotr Jasiukajtis double y[2], z = 0.0; 5025c28e83SPiotr Jasiukajtis int n, ix; 5125c28e83SPiotr Jasiukajtis 5225c28e83SPiotr Jasiukajtis /* high word of x */ 5325c28e83SPiotr Jasiukajtis ix = ((int *) &x)[HIWORD]; 5425c28e83SPiotr Jasiukajtis 5525c28e83SPiotr Jasiukajtis /* |x| ~< pi/4 */ 5625c28e83SPiotr Jasiukajtis ix &= 0x7fffffff; 5725c28e83SPiotr Jasiukajtis if (ix <= 0x3fe921fb) 5825c28e83SPiotr Jasiukajtis return (__k_tan(x, z, 0)); 5925c28e83SPiotr Jasiukajtis 6025c28e83SPiotr Jasiukajtis /* tan(Inf or NaN) is NaN */ 6125c28e83SPiotr Jasiukajtis else if (ix >= 0x7ff00000) { 6225c28e83SPiotr Jasiukajtis #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN) 6325c28e83SPiotr Jasiukajtis return (ix >= 0x7ff80000 ? x : x - x); /* NaN */ 6425c28e83SPiotr Jasiukajtis /* assumes sparc-like QNaN */ 6525c28e83SPiotr Jasiukajtis #else 6625c28e83SPiotr Jasiukajtis return (x - x); /* NaN */ 6725c28e83SPiotr Jasiukajtis #endif 6825c28e83SPiotr Jasiukajtis } 6925c28e83SPiotr Jasiukajtis 7025c28e83SPiotr Jasiukajtis /* argument reduction needed */ 7125c28e83SPiotr Jasiukajtis else { 7225c28e83SPiotr Jasiukajtis n = __rem_pio2(x, y); 7325c28e83SPiotr Jasiukajtis return (__k_tan(y[0], y[1], n & 1)); 7425c28e83SPiotr Jasiukajtis } 7525c28e83SPiotr Jasiukajtis } 76