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 30ddc0e0b5SRichard Lowe #pragma weak __asinl = asinl 3125c28e83SPiotr Jasiukajtis 3225c28e83SPiotr Jasiukajtis /* 3325c28e83SPiotr Jasiukajtis * asinl(x) = atan2l(x,sqrt(1-x*x)); 3425c28e83SPiotr Jasiukajtis * 3525c28e83SPiotr Jasiukajtis * For better accuracy, 1-x*x is computed as follows 3625c28e83SPiotr Jasiukajtis * 1-x*x if x < 0.5, 3725c28e83SPiotr Jasiukajtis * 2*(1-|x|)-(1-|x|)*(1-|x|) if x >= 0.5. 3825c28e83SPiotr Jasiukajtis * 3925c28e83SPiotr Jasiukajtis * Special cases: 4025c28e83SPiotr Jasiukajtis * if x is NaN, return x itself; 4125c28e83SPiotr Jasiukajtis * if |x|>1, return NaN with invalid signal. 4225c28e83SPiotr Jasiukajtis */ 4325c28e83SPiotr Jasiukajtis 4425c28e83SPiotr Jasiukajtis #include "libm.h" 4525c28e83SPiotr Jasiukajtis 4625c28e83SPiotr Jasiukajtis static const long double zero = 0.0L, small = 1.0e-20L, half = 0.5L, one = 1.0L; 4725c28e83SPiotr Jasiukajtis #ifndef lint 4825c28e83SPiotr Jasiukajtis static const long double big = 1.0e+20L; 4925c28e83SPiotr Jasiukajtis #endif 5025c28e83SPiotr Jasiukajtis 5125c28e83SPiotr Jasiukajtis long double 5225c28e83SPiotr Jasiukajtis asinl(long double x) { 5325c28e83SPiotr Jasiukajtis long double t, w; 54*61ec6b12SGordon Ross #ifndef lint 5525c28e83SPiotr Jasiukajtis volatile long double dummy; 56*61ec6b12SGordon Ross #endif 5725c28e83SPiotr Jasiukajtis 5825c28e83SPiotr Jasiukajtis w = fabsl(x); 5925c28e83SPiotr Jasiukajtis if (isnanl(x)) 6025c28e83SPiotr Jasiukajtis return (x + x); 6125c28e83SPiotr Jasiukajtis else if (w <= half) { 6225c28e83SPiotr Jasiukajtis if (w < small) { 6325c28e83SPiotr Jasiukajtis #ifndef lint 6425c28e83SPiotr Jasiukajtis dummy = w + big; 6525c28e83SPiotr Jasiukajtis /* inexact if w != 0 */ 6625c28e83SPiotr Jasiukajtis #endif 6725c28e83SPiotr Jasiukajtis return (x); 6825c28e83SPiotr Jasiukajtis } else 6925c28e83SPiotr Jasiukajtis return (atanl(x / sqrtl(one - x * x))); 7025c28e83SPiotr Jasiukajtis } else if (w < one) { 7125c28e83SPiotr Jasiukajtis t = one - w; 7225c28e83SPiotr Jasiukajtis w = t + t; 7325c28e83SPiotr Jasiukajtis return (atanl(x / sqrtl(w - t * t))); 7425c28e83SPiotr Jasiukajtis } else if (w == one) 7525c28e83SPiotr Jasiukajtis return (atan2l(x, zero)); /* asin(+-1) = +- PI/2 */ 7625c28e83SPiotr Jasiukajtis else 7725c28e83SPiotr Jasiukajtis return (zero / zero); /* |x| > 1: invalid */ 7825c28e83SPiotr Jasiukajtis } 79