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 logb = __logb 32*25c28e83SPiotr Jasiukajtis #pragma weak _logb = __logb 33*25c28e83SPiotr Jasiukajtis #endif 34*25c28e83SPiotr Jasiukajtis 35*25c28e83SPiotr Jasiukajtis #include "libm.h" 36*25c28e83SPiotr Jasiukajtis #include "xpg6.h" /* __xpg6 */ 37*25c28e83SPiotr Jasiukajtis #define _C99SUSv3_logb _C99SUSv3_logb_subnormal_is_like_ilogb 38*25c28e83SPiotr Jasiukajtis 39*25c28e83SPiotr Jasiukajtis #if defined(USE_FPSCALE) || defined(__x86) 40*25c28e83SPiotr Jasiukajtis static const double two52 = 4503599627370496.0; 41*25c28e83SPiotr Jasiukajtis #else 42*25c28e83SPiotr Jasiukajtis /* 43*25c28e83SPiotr Jasiukajtis * v: high part of a non-zero subnormal |x|; w: low part of |x| 44*25c28e83SPiotr Jasiukajtis */ 45*25c28e83SPiotr Jasiukajtis static int 46*25c28e83SPiotr Jasiukajtis ilogb_subnormal(unsigned v, unsigned w) { 47*25c28e83SPiotr Jasiukajtis int r = -1022 - 52; 48*25c28e83SPiotr Jasiukajtis 49*25c28e83SPiotr Jasiukajtis if (v) 50*25c28e83SPiotr Jasiukajtis r += 32; 51*25c28e83SPiotr Jasiukajtis else 52*25c28e83SPiotr Jasiukajtis v = w; 53*25c28e83SPiotr Jasiukajtis if (v & 0xffff0000) 54*25c28e83SPiotr Jasiukajtis r += 16, v >>= 16; 55*25c28e83SPiotr Jasiukajtis if (v & 0xff00) 56*25c28e83SPiotr Jasiukajtis r += 8, v >>= 8; 57*25c28e83SPiotr Jasiukajtis if (v & 0xf0) 58*25c28e83SPiotr Jasiukajtis r += 4, v >>= 4; 59*25c28e83SPiotr Jasiukajtis v <<= 1; 60*25c28e83SPiotr Jasiukajtis return (r + ((0xffffaa50 >> v) & 0x3)); 61*25c28e83SPiotr Jasiukajtis } 62*25c28e83SPiotr Jasiukajtis #endif /* defined(USE_FPSCALE) */ 63*25c28e83SPiotr Jasiukajtis 64*25c28e83SPiotr Jasiukajtis double 65*25c28e83SPiotr Jasiukajtis logb(double x) { 66*25c28e83SPiotr Jasiukajtis int *px = (int *) &x, k = px[HIWORD] & ~0x80000000; 67*25c28e83SPiotr Jasiukajtis 68*25c28e83SPiotr Jasiukajtis if (k < 0x00100000) { 69*25c28e83SPiotr Jasiukajtis if ((px[LOWORD] | k) == 0) 70*25c28e83SPiotr Jasiukajtis return (_SVID_libm_err(x, x, 45)); 71*25c28e83SPiotr Jasiukajtis else if ((__xpg6 & _C99SUSv3_logb) != 0) { 72*25c28e83SPiotr Jasiukajtis #if defined(USE_FPSCALE) || defined(__x86) 73*25c28e83SPiotr Jasiukajtis x *= two52; 74*25c28e83SPiotr Jasiukajtis return ((double) (((px[HIWORD] & 0x7ff00000) >> 20) 75*25c28e83SPiotr Jasiukajtis - 1075)); 76*25c28e83SPiotr Jasiukajtis #else 77*25c28e83SPiotr Jasiukajtis return ((double) ilogb_subnormal(k, px[LOWORD])); 78*25c28e83SPiotr Jasiukajtis #endif 79*25c28e83SPiotr Jasiukajtis } else 80*25c28e83SPiotr Jasiukajtis return (-1022.0); 81*25c28e83SPiotr Jasiukajtis } else if (k < 0x7ff00000) 82*25c28e83SPiotr Jasiukajtis return ((double) ((k >> 20) - 1023)); 83*25c28e83SPiotr Jasiukajtis else 84*25c28e83SPiotr Jasiukajtis return (x * x); 85*25c28e83SPiotr Jasiukajtis } 86