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 /*
  27  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 
  31 #pragma weak fmaxl = __fmaxl
  32 
  33 #include "libm.h"                       /* for isgreaterequal macro */
  34 
  35 long double
  36 __fmaxl(long double x, long double y)
  37 {
  38         union {
  39 #if defined(__sparc)
  40                 unsigned i[4];
  41 #elif defined(__x86)
  42                 unsigned i[3];
  43 #else
  44 #error Unknown architecture
  45 #endif
  46 
  47                 long double ld;
  48         } xx, yy;
  49 
  50         unsigned s;
  51 
  52         /* if y is nan, replace it by x */
  53         if (y != y)
  54                 y = x;
  55 
  56         /* if x is nan, replace it by y */
  57         if (x != x)
  58                 x = y;
  59 
  60         /* At this point, x and y are either both numeric, or both NaN */
  61         if (!isnan(x) && !isgreaterequal(x, y))
  62                 x = y;
  63 
  64         /*
  65          * clear the sign of the result if either x or y has its sign clear
  66          */
  67         xx.ld = x;
  68         yy.ld = y;
  69 #if defined(__sparc)
  70         s = ~(xx.i[0] & yy.i[0]) & 0x80000000;
  71         xx.i[0] &= ~s;
  72 #elif defined(__x86)
  73         s = ~(xx.i[2] & yy.i[2]) & 0x8000;
  74         xx.i[2] &= ~s;
  75 #else
  76 #error Unknown architecture
  77 #endif
  78 
  79         return (xx.ld);
  80 }