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 frexpf = __frexpf
  32 
  33 #include "libm.h"
  34 
  35 float
  36 __frexpf(float x, int *exp)
  37 {
  38         union {
  39                 unsigned i;
  40                 float f;
  41         } xx;
  42 
  43         unsigned hx;
  44         int e;
  45 
  46         xx.f = x;
  47         hx = xx.i & ~0x80000000;
  48 
  49         if (hx >= 0x7f800000) {              /* x is infinite or NaN */
  50                 *exp = 0;
  51                 return (x);
  52         }
  53 
  54         e = 0;
  55 
  56         if (hx < 0x00800000) {               /* x is subnormal or zero */
  57                 if (hx == 0) {
  58                         *exp = 0;
  59                         return (x);
  60                 }
  61 
  62                 /* normalize x by regarding it as an integer */
  63                 xx.f = (int)xx.i < 0 ? -(int)hx : (int)hx;
  64                 hx = xx.i & ~0x80000000;
  65                 e = -149;
  66         }
  67 
  68         /* now xx.f is normal */
  69         xx.i = (xx.i & ~0x7f800000) | 0x3f000000;
  70         *exp = e + (hx >> 23) - 0x7e;
  71         return (xx.f);
  72 }