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 __scalbl = scalbl
  32 
  33 /*
  34  * scalbl(x,n): return x * 2^n by manipulating exponent.
  35  */
  36 
  37 #include "libm.h"
  38 
  39 #define n0      0
  40 
  41 long double
  42 scalbl(long double x, long double fn)
  43 {
  44         int *py = (int *)&fn, n;
  45         long double z;
  46 
  47         if (isnanl(x) || isnanl(fn))
  48                 return (x * fn);
  49 
  50         /*
  51          * fn is inf or NaN
  52          */
  53         if ((py[n0] & 0x7fff0000) == 0x7fff0000) {
  54                 if ((py[n0] & 0x80000000) != 0)
  55                         return (x / (-fn));
  56                 else
  57                         return (x * fn);
  58         }
  59 
  60         if (rintl(fn) != fn)
  61                 return ((fn - fn) / (fn - fn));
  62 
  63         if (fn > 65000.0L) {
  64                 z = scalbnl(x, 65000);
  65         } else if (-fn > 65000.0L) {
  66                 z = scalbnl(x, -65000);
  67         } else {
  68                 n = (int)fn;
  69                 z = scalbnl(x, n);
  70         }
  71 
  72         return (z);
  73 }