usr/src/lib/libc/amd64/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 #include <sys/isa_defs.h>
  30
  31 #define CSR_DEFAULT 0x1f80
  32
  33 /*
  34  * Returns IEEE mode/status and
  35  * sets up standard environment for base conversion.
  36  */
  37 void
  38 __get_ieee_flags(__ieee_flags_type *b) {
  39         extern void _getmxcsr(), _putmxcsr();
  40
  41         _getmxcsr(&b->status);
  42
  43         /* round-to-nearest, all exceptions masked, gradual underflow */
  44         _putmxcsr(CSR_DEFAULT);
  45 }
  46
  47 /*
  48  * Restores previous IEEE mode/status
  49  */
  50 void
  51 __set_ieee_flags(__ieee_flags_type *b) {
  52         extern void _putmxcsr();
  53
  54         _putmxcsr(b->status);
  55 }