1 /* $OpenBSD: divsfm.c,v 1.5 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 /* @(#)divsfm.c: Revision: 1.6.88.1 Date: 93/12/07 15:05:51 */
16
17 #include "md.h"
18
19 void
divsfm(opnd1,opnd2,result)20 divsfm(opnd1,opnd2,result)
21 int opnd1, opnd2;
22 struct mdsfu_register *result;
23 {
24 register 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 /*
44 * check for overflow
45 *
46 * if abs(opnd1) < 0, then opnd1 = -2**31
47 * and abs(opnd1) >= abs(opnd2) always
48 */
49 if (opnd1 >= opnd2 || opnd1 < 0) {
50 /* check for opnd2 = -2**31 */
51 if (opnd2 < 0 && opnd1 != opnd2) {
52 result_hi = 0; /* remainder = 0 */
53 result_lo = opnd1 << 1;
54 }
55 else {
56 overflow = TRUE;
57 return;
58 }
59 }
60 else {
61 /* do the divide */
62 divu(opnd1,0,opnd2,result);
63
64 /* return positive residue */
65 if (op1_sign && result_hi) {
66 result_hi = opnd2 - result_hi;
67 result_lo++;
68 }
69 }
70
71 /* check for overflow */
72 if (result_lo < 0) {
73 overflow = TRUE;
74 return;
75 }
76 overflow = FALSE;
77
78 /* return appropriately signed result */
79 if (sign<0) result_lo = -result_lo;
80 return;
81 }
82