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 __log1pl = log1pl 3125c28e83SPiotr Jasiukajtis 3225c28e83SPiotr Jasiukajtis /* 3325c28e83SPiotr Jasiukajtis * log1pl(x) 3425c28e83SPiotr Jasiukajtis * Kahan's trick based on log(1+x)/x being a slow varying function. 3525c28e83SPiotr Jasiukajtis */ 3625c28e83SPiotr Jasiukajtis 3725c28e83SPiotr Jasiukajtis #include "libm.h" 3825c28e83SPiotr Jasiukajtis 3925c28e83SPiotr Jasiukajtis #if defined(__x86) 4025c28e83SPiotr Jasiukajtis #define __swapRD __swap87RD 4125c28e83SPiotr Jasiukajtis #endif 4225c28e83SPiotr Jasiukajtis extern enum fp_direction_type __swapRD(enum fp_direction_type); 4325c28e83SPiotr Jasiukajtis 4425c28e83SPiotr Jasiukajtis long double 4525c28e83SPiotr Jasiukajtis log1pl(long double x) { 4625c28e83SPiotr Jasiukajtis long double y; 4725c28e83SPiotr Jasiukajtis enum fp_direction_type rd; 4825c28e83SPiotr Jasiukajtis 4925c28e83SPiotr Jasiukajtis if (x != x) 5025c28e83SPiotr Jasiukajtis return (x + x); 5125c28e83SPiotr Jasiukajtis if (x < -1.L) 5225c28e83SPiotr Jasiukajtis return (logl(x)); 5325c28e83SPiotr Jasiukajtis rd = __swapRD(fp_nearest); 5425c28e83SPiotr Jasiukajtis y = 1.L + x; 5525c28e83SPiotr Jasiukajtis if (y != 1.L) { 5625c28e83SPiotr Jasiukajtis if (y == x) 5725c28e83SPiotr Jasiukajtis x = logl(x); 5825c28e83SPiotr Jasiukajtis else 5925c28e83SPiotr Jasiukajtis x *= logl(y) / (y - 1.L); 6025c28e83SPiotr Jasiukajtis } 6125c28e83SPiotr Jasiukajtis if (rd != fp_nearest) 6225c28e83SPiotr Jasiukajtis (void) __swapRD(rd); 6325c28e83SPiotr Jasiukajtis return (x); 6425c28e83SPiotr Jasiukajtis } 65