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 __nextafter = nextafter 30 #pragma weak _nextafter = nextafter 31 32 #include "libm.h" 33 #include <float.h> /* DBL_MIN */ 34 35 double 36 nextafter(double x, double y) { 37 int hx, hy, k; 38 double ans; 39 unsigned lx; 40 volatile double dummy; 41 42 hx = ((int *)&x)[HIWORD]; 43 lx = ((int *)&x)[LOWORD]; 44 hy = ((int *)&y)[HIWORD]; 45 k = (hx & ~0x80000000) | lx; 46 47 if (x == y) 48 return (y); /* C99 requirement */ 49 if (x != x || y != y) 50 return (x * y); 51 if (k == 0) { /* x = 0 */ 52 k = hy & 0x80000000; 53 ((int *)&ans)[HIWORD] = k; 54 ((int *)&ans)[LOWORD] = 1; 55 } else if (hx >= 0) { 56 if (x > y) { 57 ((int *)&ans)[LOWORD] = lx - 1; 58 k = (lx == 0)? hx - 1 : hx; 59 ((int *)&ans)[HIWORD] = k; 60 } else { 61 ((int *)&ans)[LOWORD] = lx + 1; 62 k = (lx == 0xffffffff)? hx + 1 : hx; 63 ((int *)&ans)[HIWORD] = k; 64 } 65 } else { 66 if (x < y) { 67 ((int *)&ans)[LOWORD] = lx - 1; 68 k = (lx == 0)? hx - 1 : hx; 69 ((int *)&ans)[HIWORD] = k; 70 } else { 71 ((int *)&ans)[LOWORD] = lx + 1; 72 k = (lx == 0xffffffff)? hx + 1 : hx; 73 ((int *)&ans)[HIWORD] = k; 74 } 75 } 76 k = (k >> 20) & 0x7ff; 77 if (k == 0x7ff) { 78 /* overflow */ 79 return (_SVID_libm_err(x, y, 46)); 80 #if !defined(__lint) 81 } else if (k == 0) { 82 /* underflow */ 83 dummy = DBL_MIN * copysign(DBL_MIN, x); 84 #endif 85 } 86 return (ans); 87 } 88