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