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 fdim = __fdim
  32 #endif
  33 
  34 /*
  35  * fdim(x,y) returns x - y if x > y, +0 if x <= y, and NaN if x and
  36  * y are unordered.
  37  *
  38  * fdim(x,y) raises overflow or inexact if x > y and x - y overflows
  39  * or is inexact.  It raises invalid if either operand is a signaling
  40  * NaN.  Otherwise, it raises no exceptions.
  41  */
  42 
  43 #include "libm.h"       /* for islessequal macro */
  44 
  45 double
  46 __fdim(double x, double y) {
  47 #if defined(COMPARISON_MACRO_BUG)
  48         if (x == x && y == y && x <= y) {    /* } */
  49 #else
  50         if (islessequal(x, y)) {
  51 #endif
  52                 x = 0.0;
  53                 y = -x;
  54         }
  55         return (x - y);
  56 }