1 /* $NetBSD: divsfm.c,v 1.5 2012/02/04 17:03:09 skrll Exp $ */
2
3 /* $OpenBSD: divsfm.c,v 1.4 2001/03/29 03:58:17 mickey Exp $ */
4
5 /*
6 * Copyright 1996 1995 by Open Software Foundation, Inc.
7 * All Rights Reserved
8 *
9 * Permission to use, copy, modify, and distribute this software and
10 * its documentation for any purpose and without fee is hereby granted,
11 * provided that the above copyright notice appears in all copies and
12 * that both the copyright notice and this permission notice appear in
13 * supporting documentation.
14 *
15 * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
16 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
17 * FOR A PARTICULAR PURPOSE.
18 *
19 * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
20 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
21 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
22 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
23 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
24 *
25 */
26 /*
27 * pmk1.1
28 */
29 /*
30 * (c) Copyright 1986 HEWLETT-PACKARD COMPANY
31 *
32 * To anyone who acknowledges that this file is provided "AS IS"
33 * without any express or implied warranty:
34 * permission to use, copy, modify, and distribute this file
35 * for any purpose is hereby granted without fee, provided that
36 * the above copyright notice and this notice appears in all
37 * copies, and that the name of Hewlett-Packard Company not be
38 * used in advertising or publicity pertaining to distribution
39 * of the software without specific, written prior permission.
40 * Hewlett-Packard Company makes no representations about the
41 * suitability of this software for any purpose.
42 */
43
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: divsfm.c,v 1.5 2012/02/04 17:03:09 skrll Exp $");
46
47 #include "md.h"
48
49 void
divsfm(int opnd1,int opnd2,struct mdsfu_register * result)50 divsfm(int opnd1, int opnd2, struct mdsfu_register *result)
51 {
52 register int sign, op1_sign;
53
54 /* check divisor for zero */
55 if (opnd2 == 0) {
56 overflow = true;
57 return;
58 }
59
60 /* get sign of result */
61 sign = opnd1 ^ opnd2;
62
63 /* get absolute value of operands */
64 if (opnd1 < 0) {
65 opnd1 = -opnd1;
66 op1_sign = true;
67 }
68 else op1_sign = false;
69 if (opnd2 < 0) opnd2 = -opnd2;
70
71 /*
72 * check for overflow
73 *
74 * if abs(opnd1) < 0, then opnd1 = -2**31
75 * and abs(opnd1) >= abs(opnd2) always
76 */
77 if (opnd1 >= opnd2 || opnd1 < 0) {
78 /* check for opnd2 = -2**31 */
79 if (opnd2 < 0 && opnd1 != opnd2) {
80 result_hi = 0; /* remainder = 0 */
81 result_lo = opnd1 << 1;
82 }
83 else {
84 overflow = true;
85 return;
86 }
87 }
88 else {
89 /* do the divide */
90 divu(opnd1,0,opnd2,result);
91
92 /* return positive residue */
93 if (op1_sign && result_hi) {
94 result_hi = opnd2 - result_hi;
95 result_lo++;
96 }
97 }
98
99 /* check for overflow */
100 if (result_lo < 0) {
101 overflow = true;
102 return;
103 }
104 overflow = false;
105
106 /* return appropriately signed result */
107 if (sign<0) result_lo = -result_lo;
108 return;
109 }
110