1*25c28e83SPiotr Jasiukajtis /* 2*25c28e83SPiotr Jasiukajtis * CDDL HEADER START 3*25c28e83SPiotr Jasiukajtis * 4*25c28e83SPiotr Jasiukajtis * The contents of this file are subject to the terms of the 5*25c28e83SPiotr Jasiukajtis * Common Development and Distribution License (the "License"). 6*25c28e83SPiotr Jasiukajtis * You may not use this file except in compliance with the License. 7*25c28e83SPiotr Jasiukajtis * 8*25c28e83SPiotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9*25c28e83SPiotr Jasiukajtis * or http://www.opensolaris.org/os/licensing. 10*25c28e83SPiotr Jasiukajtis * See the License for the specific language governing permissions 11*25c28e83SPiotr Jasiukajtis * and limitations under the License. 12*25c28e83SPiotr Jasiukajtis * 13*25c28e83SPiotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each 14*25c28e83SPiotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15*25c28e83SPiotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the 16*25c28e83SPiotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying 17*25c28e83SPiotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner] 18*25c28e83SPiotr Jasiukajtis * 19*25c28e83SPiotr Jasiukajtis * CDDL HEADER END 20*25c28e83SPiotr Jasiukajtis */ 21*25c28e83SPiotr Jasiukajtis 22*25c28e83SPiotr Jasiukajtis /* 23*25c28e83SPiotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24*25c28e83SPiotr Jasiukajtis */ 25*25c28e83SPiotr Jasiukajtis /* 26*25c28e83SPiotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27*25c28e83SPiotr Jasiukajtis * Use is subject to license terms. 28*25c28e83SPiotr Jasiukajtis */ 29*25c28e83SPiotr Jasiukajtis 30*25c28e83SPiotr Jasiukajtis #if defined(ELFOBJ) 31*25c28e83SPiotr Jasiukajtis #pragma weak log1pl = __log1pl 32*25c28e83SPiotr Jasiukajtis #endif 33*25c28e83SPiotr Jasiukajtis 34*25c28e83SPiotr Jasiukajtis /* 35*25c28e83SPiotr Jasiukajtis * log1pl(x) 36*25c28e83SPiotr Jasiukajtis * Kahan's trick based on log(1+x)/x being a slow varying function. 37*25c28e83SPiotr Jasiukajtis */ 38*25c28e83SPiotr Jasiukajtis 39*25c28e83SPiotr Jasiukajtis #include "libm.h" 40*25c28e83SPiotr Jasiukajtis 41*25c28e83SPiotr Jasiukajtis #if defined(__x86) 42*25c28e83SPiotr Jasiukajtis #define __swapRD __swap87RD 43*25c28e83SPiotr Jasiukajtis #endif 44*25c28e83SPiotr Jasiukajtis extern enum fp_direction_type __swapRD(enum fp_direction_type); 45*25c28e83SPiotr Jasiukajtis 46*25c28e83SPiotr Jasiukajtis long double 47*25c28e83SPiotr Jasiukajtis log1pl(long double x) { 48*25c28e83SPiotr Jasiukajtis long double y; 49*25c28e83SPiotr Jasiukajtis enum fp_direction_type rd; 50*25c28e83SPiotr Jasiukajtis 51*25c28e83SPiotr Jasiukajtis if (x != x) 52*25c28e83SPiotr Jasiukajtis return (x + x); 53*25c28e83SPiotr Jasiukajtis if (x < -1.L) 54*25c28e83SPiotr Jasiukajtis return (logl(x)); 55*25c28e83SPiotr Jasiukajtis rd = __swapRD(fp_nearest); 56*25c28e83SPiotr Jasiukajtis y = 1.L + x; 57*25c28e83SPiotr Jasiukajtis if (y != 1.L) { 58*25c28e83SPiotr Jasiukajtis if (y == x) 59*25c28e83SPiotr Jasiukajtis x = logl(x); 60*25c28e83SPiotr Jasiukajtis else 61*25c28e83SPiotr Jasiukajtis x *= logl(y) / (y - 1.L); 62*25c28e83SPiotr Jasiukajtis } 63*25c28e83SPiotr Jasiukajtis if (rd != fp_nearest) 64*25c28e83SPiotr Jasiukajtis (void) __swapRD(rd); 65*25c28e83SPiotr Jasiukajtis return (x); 66*25c28e83SPiotr Jasiukajtis } 67