1 /* $OpenBSD: divsir.c,v 1.6 2002/05/07 22:19:30 mickey Exp $ */
2 /*
3 (c) Copyright 1986 HEWLETT-PACKARD COMPANY
4 To anyone who acknowledges that this file is provided "AS IS"
5 without any express or implied warranty:
6 permission to use, copy, modify, and distribute this file
7 for any purpose is hereby granted without fee, provided that
8 the above copyright notice and this notice appears in all
9 copies, and that the name of Hewlett-Packard Company not be
10 used in advertising or publicity pertaining to distribution
11 of the software without specific, written prior permission.
12 Hewlett-Packard Company makes no representations about the
13 suitability of this software for any purpose.
14 */
15 /* @(#)divsir.c: Revision: 1.6.88.1 Date: 93/12/07 15:05:58 */
16
17 #include "md.h"
18
19 void
divsir(opnd1,opnd2,result)20 divsir(opnd1,opnd2,result)
21 int opnd1, opnd2;
22 struct mdsfu_register *result;
23 {
24 int sign, op1_sign;
25
26 /* check divisor for zero */
27 if (opnd2 == 0) {
28 overflow = TRUE;
29 return;
30 }
31
32 /* get sign of result */
33 sign = opnd1 ^ opnd2;
34
35 /* get absolute value of operands */
36 if (opnd1 < 0) {
37 opnd1 = -opnd1;
38 op1_sign = TRUE;
39 }
40 else op1_sign = FALSE;
41 if (opnd2 < 0) opnd2 = -opnd2;
42
43 /* check for opnd2 = -2**31 */
44 if (opnd2 + opnd2 == 0) {
45 if (opnd1 == opnd2) {
46 result_hi = 0; /* remainder = 0 */
47 result_lo = 1;
48 }
49 else {
50 result_hi = opnd1; /* remainder = opnd1 */
51 result_lo = 0;
52 }
53 }
54 else {
55 /* do the divide */
56 divu(0,opnd1,opnd2,result);
57
58 /*
59 * check for overflow
60 *
61 * at this point, the only way we can get overflow
62 * is with opnd1 = -2**31 and opnd2 = -1
63 */
64 if (sign>0 && result_lo<0) {
65 overflow = TRUE;
66 return;
67 }
68 }
69 overflow = FALSE;
70
71 /* return appropriately signed remainder and result */
72 if (op1_sign) result_hi = -result_hi;
73 if (sign<0) result_lo = -result_lo;
74 return;
75 }
76