usr/src/lib/libc/i386/fp/ieee.c

   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 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #include "lint.h"
  28 #include "base_conversion.h"
  29
  30 /*
  31  * Returns IEEE mode/status and
  32  * sets up standard environment for base conversion.
  33  */
  34 void
  35 __get_ieee_flags(__ieee_flags_type *b) {
  36         extern void _getcw(), _getsw(), _putcw();
  37         int cw;
  38
  39         _getcw(&cw);
  40         b->mode = cw;
  41         _getsw(&b->status);
  42         /*
  43          * set CW to...
  44          * RC (bits 10:11)      0 == round to nearest even
  45          * PC (bits 8:9)        2 == round to double
  46          * EM (bits 0:5)        0x3f == all exception trapping masked off
  47          */
  48         cw = (cw & ~0xf3f) | 0x23f;
  49         _putcw(cw);
  50 }
  51
  52 /*
  53  * Restores previous IEEE mode/status
  54  */
  55 void
  56 __set_ieee_flags(__ieee_flags_type *b) {
  57         extern void _putcw(), _putsw();
  58
  59         _putcw(b->mode);
  60         _putsw(b->status);
  61 }