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 round = __round 32 #endif 33 34 #include "libm.h" 35 36 double 37 round(double x) { 38 union { 39 unsigned i[2]; 40 double d; 41 } xx; 42 unsigned hx, sx, i; 43 44 xx.d = x; 45 hx = xx.i[HIWORD] & ~0x80000000; 46 sx = xx.i[HIWORD] & 0x80000000; 47 if (hx < 0x43300000) { /* |x| < 2^52 */ 48 if (hx < 0x3ff00000) { /* |x| < 1 */ 49 if (hx >= 0x3fe00000) 50 return (sx ? -1.0 : 1.0); 51 return (sx ? -0.0 : 0.0); 52 } 53 54 /* round x at the integer bit */ 55 if (hx < 0x41300000) { 56 i = 1 << (0x412 - (hx >> 20)); 57 xx.i[HIWORD] = (xx.i[HIWORD] + i) & ~(i | (i - 1)); 58 xx.i[LOWORD] = 0; 59 } else { 60 i = 1 << (0x432 - (hx >> 20)); 61 xx.i[LOWORD] += i; 62 if (xx.i[LOWORD] < i) 63 xx.i[HIWORD]++; 64 xx.i[LOWORD] &= ~(i | (i - 1)); 65 } 66 return (xx.d); 67 } else if (hx < 0x7ff00000) 68 return (x); 69 else 70 #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN) 71 return (hx >= 0x7ff80000 ? x : x + x); 72 /* assumes sparc-like QNaN */ 73 #else 74 return (x + x); 75 #endif 76 } 77