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 #pragma weak scalbl = __scalbl
  31 
  32 /*
  33  * scalbl(x,n): return x * 2^n by manipulating exponent.
  34  */
  35 
  36 #include "libm.h"
  37 
  38 #define n0      0
  39 
  40 long double
  41 scalbl(long double x, long double fn) {
  42         int *py = (int *) &fn, n;
  43         long double z;
  44 
  45         if (isnanl(x) || isnanl(fn))
  46                 return (x * fn);
  47 
  48         /*
  49          * fn is inf or NaN
  50          */
  51         if ((py[n0] & 0x7fff0000) == 0x7fff0000) {
  52                 if ((py[n0] & 0x80000000) != 0)
  53                         return (x / (-fn));
  54                 else
  55                         return (x * fn);
  56         }
  57         if (rintl(fn) != fn)
  58                 return ((fn - fn) / (fn - fn));
  59         if (fn > 65000.0L)
  60                 z = scalbnl(x, 65000);
  61         else if (-fn > 65000.0L)
  62                 z = scalbnl(x, -65000);
  63         else {
  64                 n = (int) fn;
  65                 z = scalbnl(x, n);
  66         }
  67         return (z);
  68 }