xref: /titanic_41/usr/src/lib/libbc/libc/gen/common/_Q_add.c (revision 5d54f3d8999eac1762fe0a8c7177d20f1f201fae)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 1988 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include "_Qquad.h"
30 #include "_Qglobals.h"
31 
32 static double zero = 0.0, tiny = 1.0e-300, huge = 1.0e300;
33 static void	dummy(double);
34 
35 QUAD
_Q_add(QUAD x,QUAD y)36 _Q_add(QUAD x, QUAD y)
37 {
38 	unpacked	px,py,pz;
39 	QUAD		z;
40 	_fp_current_exceptions = 0;
41 	_Q_get_rp_rd();		/* get fp_precision, fp_direction */
42 	_fp_unpack(&px,(int *)&x,fp_op_extended);
43 	_fp_unpack(&py,(int *)&y,fp_op_extended);
44 	_fp_add(&px,&py,&pz);
45 	_fp_pack(&pz,(int *)&z,fp_op_extended);
46 	_Q_set_exception(_fp_current_exceptions);
47 	return (z);
48 }
49 
50 void
_Q_set_exception(unsigned ex)51 _Q_set_exception(unsigned ex)
52 {
53     /* simulate exceptions using double arithmetic */
54 	double t;
55 	if((ex&(1<<fp_invalid))!=0)	t = (zero/zero);
56 	if((ex&(1<<fp_overflow))!=0)	t = (huge*huge);
57 	if((ex&(1<<fp_underflow))!=0)	t = (tiny*tiny);
58 	if((ex&(1<<fp_division))!=0)	t = (tiny/zero);
59 	if((ex&(1<<fp_inexact))!=0)	t = (huge+tiny);
60 	dummy(t);  /* prevent optimizer eliminating previous expression */
61 }
62 
63 static void
dummy(double x)64 dummy(double x)
65 {
66 }
67