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 __cbrtl = cbrtl 3125c28e83SPiotr Jasiukajtis 3225c28e83SPiotr Jasiukajtis #include "libm.h" 3325c28e83SPiotr Jasiukajtis #include "longdouble.h" 3425c28e83SPiotr Jasiukajtis 3525c28e83SPiotr Jasiukajtis #define n0 0 3625c28e83SPiotr Jasiukajtis 3725c28e83SPiotr Jasiukajtis long double 3825c28e83SPiotr Jasiukajtis cbrtl(long double x) { 3925c28e83SPiotr Jasiukajtis long double s, t, r, w, y; 4025c28e83SPiotr Jasiukajtis double dx, dy; 4125c28e83SPiotr Jasiukajtis int *py = (int *) &dy; 4225c28e83SPiotr Jasiukajtis int n, m, m3, sx; 4325c28e83SPiotr Jasiukajtis 4425c28e83SPiotr Jasiukajtis if (!finitel(x)) 4525c28e83SPiotr Jasiukajtis return (x + x); 4625c28e83SPiotr Jasiukajtis if (iszerol(x)) 4725c28e83SPiotr Jasiukajtis return (x); 4825c28e83SPiotr Jasiukajtis sx = signbitl(x); 4925c28e83SPiotr Jasiukajtis x = fabsl(x); 5025c28e83SPiotr Jasiukajtis n = ilogbl(x); 5125c28e83SPiotr Jasiukajtis m = n / 3; 5225c28e83SPiotr Jasiukajtis m3 = m + m + m; 5325c28e83SPiotr Jasiukajtis y = scalbnl(x, -m3); 5425c28e83SPiotr Jasiukajtis dx = (double) y; 5525c28e83SPiotr Jasiukajtis dy = cbrt(dx); 5625c28e83SPiotr Jasiukajtis py[1 - n0] += 2; 5725c28e83SPiotr Jasiukajtis if (py[1 - n0] == 0) 5825c28e83SPiotr Jasiukajtis py[n0] += 1; 5925c28e83SPiotr Jasiukajtis 6025c28e83SPiotr Jasiukajtis /* one step newton iteration to 113 bits with error < 0.667ulps */ 6125c28e83SPiotr Jasiukajtis t = (long double) dy; 6225c28e83SPiotr Jasiukajtis t = scalbnl(t, m); 6325c28e83SPiotr Jasiukajtis s = t * t; 6425c28e83SPiotr Jasiukajtis r = x / s; 6525c28e83SPiotr Jasiukajtis w = t + t; 6625c28e83SPiotr Jasiukajtis r = (r - t) / (w + r); 6725c28e83SPiotr Jasiukajtis t += t * r; 6825c28e83SPiotr Jasiukajtis 6925c28e83SPiotr Jasiukajtis return (sx == 0 ? t : -t); 7025c28e83SPiotr Jasiukajtis } 71