1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24 */ 25 /* 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27 * Use is subject to license terms. 28 */ 29 30 #if defined(ELFOBJ) 31 #pragma weak scalbnl = __scalbnl 32 #endif 33 34 #include "libm.h" 35 #include <float.h> /* LDBL_MAX, LDBL_MIN */ 36 #include <stdlib.h> /* abs */ 37 38 #if defined(__sparc) 39 #define XSET_EXP(k, x) ((int *) &x)[0] = (((int *) &x)[0] & ~0x7fff0000) | \ 40 (k << 16) 41 #define ISINFNANL(k, x) (k == 0x7fff) 42 #define XTWOT_OFFSET 113 43 static const long double xtwot = 10384593717069655257060992658440192.0L, 44 /* 2^113 */ 45 twomtm1 = 4.814824860968089632639944856462318296E-35L; /* 2^-114 */ 46 #elif defined(__x86) 47 #define XSET_EXP(k, x) ((int *) &x)[2] = (((int *) &x)[2] & ~0x7fff) | k 48 #if defined(HANDLE_UNSUPPORTED) 49 #define ISINFNANL(k, x) (k == 0x7fff || k != 0 && \ 50 (((int *) &x)[1] & 0x80000000) == 0) 51 #else 52 #define ISINFNANL(k, x) (k == 0x7fff) 53 #endif 54 #define XTWOT_OFFSET 64 55 static const long double xtwot = 18446744073709551616.0L, /* 2^64 */ 56 twomtm1 = 2.7105054312137610850186E-20L; /* 2^-65 */ 57 #endif 58 59 long double 60 scalbnl(long double x, int n) { 61 int k = XBIASED_EXP(x); 62 63 if (ISINFNANL(k, x)) 64 return (x + x); 65 if (ISZEROL(x) || n == 0) 66 return (x); 67 if (k == 0) { 68 x *= xtwot; 69 k = XBIASED_EXP(x) - XTWOT_OFFSET; 70 } 71 if ((unsigned) abs(n) >= 131072) /* cast to unsigned for -2^31 */ 72 n >>= 1; /* avoid subsequent integer overflow */ 73 k += n; 74 if (k > 0x7ffe) 75 return (LDBL_MAX * copysignl(LDBL_MAX, x)); 76 if (k <= -XTWOT_OFFSET - 1) 77 return (LDBL_MIN * copysignl(LDBL_MIN, x)); 78 if (k > 0) { 79 XSET_EXP(k, x); 80 return (x); 81 } 82 k += XTWOT_OFFSET + 1; 83 XSET_EXP(k, x); 84 return (x * twomtm1); 85 } 86