xref: /illumos-gate/usr/src/lib/libc/port/gen/lmath.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 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved	*/
29 
30 /*
31  * This set of routines used to be implemented mostly in assembler.
32  *
33  * Since the purpose they have is now rather vestigial, and 64-bit
34  * machines can do operations on 64-bit quantities pretty efficiently,
35  * a C implementation seems quite adequate and much more maintainable.
36  */
37 
38 #include "lint.h"
39 #include <sys/types.h>
40 #include <sys/dl.h>
41 
42 typedef union {
43 	long	xword;
44 	dl_t	dl;
45 } dlx_t;
46 
47 dl_t
ladd(dl_t lop,dl_t rop)48 ladd(dl_t lop, dl_t rop)
49 {
50 	dlx_t r;
51 	/* LINTED pointer cast may result in improper alignment */
52 	r.xword = *(long *)&lop + *(long *)&rop;
53 	return (r.dl);
54 }
55 
56 dl_t
lshiftl(dl_t op,int cnt)57 lshiftl(dl_t op, int cnt)
58 {
59 	dlx_t r;
60 	if (cnt < 0)
61 		/* LINTED pointer cast may result in improper alignment */
62 		r.xword = (long)(*(ulong_t *)&op >> (-cnt));
63 	else
64 		/* LINTED pointer cast may result in improper alignment */
65 		r.xword = *(long *)&op << cnt;
66 	return (r.dl);
67 }
68 
69 int
lsign(dl_t op)70 lsign(dl_t op)
71 {
72 	/* LINTED pointer cast may result in improper alignment */
73 	return ((*(long *)&op) >> 63);
74 }
75 
76 dl_t
lsub(dl_t lop,dl_t rop)77 lsub(dl_t lop, dl_t rop)
78 {
79 	dlx_t r;
80 	/* LINTED pointer cast may result in improper alignment */
81 	r.xword = *(long *)&lop - *(long *)&rop;
82 	return (r.dl);
83 }
84 
85 dl_t
lmul(dl_t lop,dl_t rop)86 lmul(dl_t lop, dl_t rop)
87 {
88 	dlx_t r;
89 	/* LINTED pointer cast may result in improper alignment */
90 	r.xword = *(long *)&lop * *(long *)&rop;
91 	return (r.dl);
92 }
93