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 modff = __modff
  31 #pragma weak _modff = __modff
  32 
  33 #include "libm.h"
  34 
  35 float
  36 __modff(float x, float *iptr) {
  37         union {
  38                 unsigned i;
  39                 float f;
  40         } xx, yy;
  41         unsigned hx, s;
  42 
  43         xx.f = x;
  44         hx = xx.i & ~0x80000000;
  45 
  46         if (hx >= 0x4b000000) {      /* x is NaN, infinite, or integral */
  47                 *iptr = x;
  48                 if (hx <= 0x7f800000)
  49                         xx.i &= 0x80000000;
  50                 return (xx.f);
  51         }
  52 
  53         if (hx < 0x3f800000) {       /* |x| < 1 */
  54                 xx.i &= 0x80000000;
  55                 *iptr = xx.f;
  56                 return (x);
  57         }
  58 
  59         /* split x at the binary point */
  60         s = xx.i & 0x80000000;
  61         yy.i = xx.i & ~((1 << (0x96 - (hx >> 23))) - 1);
  62         *iptr = yy.f;
  63         xx.f -= yy.f;
  64         xx.i = (xx.i & ~0x80000000) | s;
  65                                 /* restore sign in case difference is 0 */
  66         return (xx.f);
  67 }