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 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 23 */ 24 /* 25 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 26 * Use is subject to license terms. 27 */ 28 29 #pragma weak floor = __floor 30 31 /* 32 * floor(x) returns the biggest integral value less than or equal to x. 33 * NOTE: floor(x) returns result with the same sign as x's, including 0. 34 * 35 * Modified 8/4/04 for performance. 36 */ 37 38 #include "libm.h" 39 40 static const double 41 zero = 0.0, 42 one = 1.0, 43 two52 = 4503599627370496.0; 44 45 double 46 floor(double x) { 47 double t, w; 48 int hx, lx, ix; 49 50 hx = ((int *)&x)[HIWORD]; 51 lx = ((int *)&x)[LOWORD]; 52 ix = hx & ~0x80000000; 53 if (ix >= 0x43300000) /* return x if |x| >= 2^52, or x is NaN */ 54 return (x * one); 55 t = (hx >= 0)? two52 : -two52; 56 w = x + t; 57 t = w - t; 58 if (ix < 0x3ff00000) { 59 if ((ix | lx) == 0) 60 return (x); 61 else 62 return ((hx < 0)? -one : zero); 63 } 64 return ((t <= x)? t : t - one); 65 } 66