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 #pragma weak __round = round 31 32 #include "libm.h" 33 34 double 35 round(double x) { 36 union { 37 unsigned i[2]; 38 double d; 39 } xx; 40 unsigned hx, sx, i; 41 42 xx.d = x; 43 hx = xx.i[HIWORD] & ~0x80000000; 44 sx = xx.i[HIWORD] & 0x80000000; 45 if (hx < 0x43300000) { /* |x| < 2^52 */ 46 if (hx < 0x3ff00000) { /* |x| < 1 */ 47 if (hx >= 0x3fe00000) 48 return (sx ? -1.0 : 1.0); 49 return (sx ? -0.0 : 0.0); 50 } 51 52 /* round x at the integer bit */ 53 if (hx < 0x41300000) { 54 i = 1 << (0x412 - (hx >> 20)); 55 xx.i[HIWORD] = (xx.i[HIWORD] + i) & ~(i | (i - 1)); 56 xx.i[LOWORD] = 0; 57 } else { 58 i = 1 << (0x432 - (hx >> 20)); 59 xx.i[LOWORD] += i; 60 if (xx.i[LOWORD] < i) 61 xx.i[HIWORD]++; 62 xx.i[LOWORD] &= ~(i | (i - 1)); 63 } 64 return (xx.d); 65 } else if (hx < 0x7ff00000) 66 return (x); 67 else 68 #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN) 69 return (hx >= 0x7ff80000 ? x : x + x); 70 /* assumes sparc-like QNaN */ 71 #else 72 return (x + x); 73 #endif 74 } 75