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 frexpf = __frexpf
  31 
  32 #include "libm.h"
  33 
  34 float
  35 __frexpf(float x, int *exp) {
  36         union {
  37                 unsigned i;
  38                 float f;
  39         } xx;
  40         unsigned hx;
  41         int e;
  42 
  43         xx.f = x;
  44         hx = xx.i & ~0x80000000;
  45 
  46         if (hx >= 0x7f800000) { /* x is infinite or NaN */
  47                 *exp = 0;
  48                 return (x);
  49         }
  50 
  51         e = 0;
  52         if (hx < 0x00800000) { /* x is subnormal or zero */
  53                 if (hx == 0) {
  54                         *exp = 0;
  55                         return (x);
  56                 }
  57 
  58                 /* normalize x by regarding it as an integer */
  59                 xx.f = (int) xx.i < 0 ? -(int) hx : (int) hx;
  60                 hx = xx.i & ~0x80000000;
  61                 e = -149;
  62         }
  63 
  64         /* now xx.f is normal */
  65         xx.i = (xx.i & ~0x7f800000) | 0x3f000000;
  66         *exp = e + (hx >> 23) - 0x7e;
  67         return (xx.f);
  68 }