1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24 */ 25 /* 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27 * Use is subject to license terms. 28 */ 29 30 #pragma weak __tanl = tanl 31 32 /* INDENT OFF */ 33 /* cosl(x) 34 * Table look-up algorithm by K.C. Ng, November, 1989. 35 * 36 * kernel function: 37 * __k_tanl ... tangent function on [-pi/4,pi/4] 38 * __rem_pio2l ... argument reduction routine 39 * 40 * Method. 41 * Let S and C denote the sin and cos respectively on [-PI/4, +PI/4]. 42 * 1. Assume the argument x is reduced to y1+y2 = x-k*pi/2 in 43 * [-pi/2 , +pi/2], and let n = k mod 4. 44 * 2. Let S=S(y1+y2), C=C(y1+y2). Depending on n, we have 45 * 46 * n sin(x) cos(x) tan(x) 47 * ---------------------------------------------------------- 48 * 0 S C S/C 49 * 1 C -S -C/S 50 * 2 -S -C S/C 51 * 3 -C S -C/S 52 * ---------------------------------------------------------- 53 * 54 * Special cases: 55 * Let trig be any of sin, cos, or tan. 56 * trig(+-INF) is NaN, with signals; 57 * trig(NaN) is that NaN; 58 * 59 * Accuracy: 60 * computer TRIG(x) returns trig(x) nearly rounded. 61 */ 62 /* INDENT ON */ 63 64 #include "libm.h" 65 #include "longdouble.h" 66 67 #include <sys/isa_defs.h> 68 69 long double 70 tanl(long double x) { 71 long double y[2], z = 0.0L; 72 int n, ix; 73 #if defined(__i386) || defined(__amd64) 74 int *px = (int *) &x; 75 #endif 76 77 /* trig(Inf or NaN) is NaN */ 78 if (!finitel(x)) 79 return x - x; 80 81 /* High word of x. */ 82 #if defined(__i386) || defined(__amd64) 83 XTOI(px, ix); 84 #else 85 ix = *(int *) &x; 86 #endif 87 88 /* |x| ~< pi/4 */ 89 ix &= 0x7fffffff; 90 if (ix <= 0x3ffe9220) 91 return __k_tanl(x, z, 0); 92 93 /* argument reduction needed */ 94 else { 95 n = __rem_pio2l(x, y); 96 return __k_tanl(y[0], y[1], n & 1); 97 } 98 } 99