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 #include "longdouble.h"
  39 
  40 #include <sys/isa_defs.h>
  41 
  42 long double
  43 scalbl(long double x, long double fn)
  44 {
  45         int *py = (int *)&fn, n;
  46         long double z;
  47 
  48         if (isnanl(x) || isnanl(fn))
  49                 return (x * fn);
  50 
  51         /* fn is +/-Inf */
  52 #if defined(_BIG_ENDIAN)
  53         if ((py[0] & 0x7fff0000) == 0x7fff0000) {
  54                 if ((py[0] & 0x80000000) != 0)
  55 #else
  56         if ((py[2] & 0x7fff) == 0x7fff) {
  57                 if ((py[2] & 0x8000) != 0)
  58 #endif
  59                         return (x / (-fn));
  60                 else
  61                         return (x * fn);
  62         }
  63 
  64         if (rintl(fn) != fn)
  65                 return ((fn - fn) / (fn - fn));
  66 
  67         if (fn > 65000.0L) {
  68                 z = scalbnl(x, 65000);
  69         } else if (-fn > 65000.0L) {
  70                 z = scalbnl(x, -65000);
  71         } else {
  72                 n = (int)fn;
  73                 z = scalbnl(x, n);
  74         }
  75 
  76         return (z);
  77 }