xref: /illumos-gate/usr/src/lib/libc/sparc/fp/_Q_set_except.c (revision 1da57d551424de5a9d469760be7c4b4d4f10a755)
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 <sys/ieeefp.h>
29 #include <ieeefp.h>
30 
31 static const double zero = 0.0, tiny = 1.0e-307, tiny2 = 1.001e-307,
32 	huge = 1.0e300;
33 
34 /*
35  * _Q_set_exception(ex) simulates the floating point exceptions indicated by
36  * ex.  This routine is not used by the new quad emulation routines but is
37  * still used by ../crt/_ftoll.c.
38  */
39 int
_Q_set_exception(unsigned int ex)40 _Q_set_exception(unsigned int ex)
41 {
42 	/* LINTED set but not used */
43 	volatile double t;
44 
45 	if (ex == 0)
46 		t = zero - zero;			/* clear cexc */
47 	else {
48 		if ((ex & (1 << fp_invalid)) != 0)
49 			t = zero / zero;
50 		if ((ex & (1 << fp_overflow)) != 0)
51 			t = huge * huge;
52 		if ((ex & (1 << fp_underflow)) != 0) {
53 			if ((ex & (1 << fp_inexact)) != 0 ||
54 			    (fpgetmask() & FP_X_UFL) != 0)
55 				t = tiny * tiny;
56 			else
57 				t = tiny2 - tiny;	/* exact */
58 		}
59 		if ((ex & (1 << fp_division)) != 0)
60 			t = tiny / zero;
61 		if ((ex & (1 << fp_inexact)) != 0)
62 			t = huge + tiny;
63 	}
64 	return (0);
65 }
66