1/*
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
|
25 */
26/*
27 * HISTORY
28 * $Log: db_expr.c,v $
29 * Revision 1.1 1992/03/25 21:45:09 pace
30 * Initial revision
|
25 *
|
32 * Revision 2.3 91/02/05 17:06:25 mrt
33 * Changed to new Mach copyright
34 * [91/01/31 16:17:46 mrt]
35 *
36 * Revision 2.2 90/08/27 21:50:57 dbg
37 * Use '..' instead of '$$' for db_prev.
38 * Use '+' for db_next.
39 * [90/08/22 dbg]
40 *
41 * Allow repeated unary operators.
42 * [90/08/20 dbg]
43 *
44 * Reflected back rename of db_symbol_value->db_value_of_name
45 * [90/08/20 af]
46 * Reduce lint.
47 * [90/08/07 dbg]
48 * Created.
49 * [90/07/25 dbg]
50 *
|
| 26 * $Id$ |
27 */
|
| 28 |
29/*
30 * Author: David B. Golub, Carnegie Mellon University
31 * Date: 7/90
32 */
33#include "param.h"
34#include "proc.h"
35#include <machine/db_machdep.h>
36#include <ddb/db_lex.h>
37#include <ddb/db_access.h>
38#include <ddb/db_command.h>
39
40boolean_t
41db_term(valuep)
42 db_expr_t *valuep;
43{
44 int t;
45
46 t = db_read_token();
47 if (t == tIDENT) {
48 if (!db_value_of_name(db_tok_string, valuep)) {
49 db_error("Symbol not found\n");
50 /*NOTREACHED*/
51 }
52 return (TRUE);
53 }
54 if (t == tNUMBER) {
55 *valuep = (db_expr_t)db_tok_number;
56 return (TRUE);
57 }
58 if (t == tDOT) {
59 *valuep = (db_expr_t)db_dot;
60 return (TRUE);
61 }
62 if (t == tDOTDOT) {
63 *valuep = (db_expr_t)db_prev;
64 return (TRUE);
65 }
66 if (t == tPLUS) {
67 *valuep = (db_expr_t) db_next;
68 return (TRUE);
69 }
70 if (t == tDITTO) {
71 *valuep = (db_expr_t)db_last_addr;
72 return (TRUE);
73 }
74 if (t == tDOLLAR) {
75 if (!db_get_variable(valuep))
76 return (FALSE);
77 return (TRUE);
78 }
79 if (t == tLPAREN) {
80 if (!db_expression(valuep)) {
81 db_error("Syntax error\n");
82 /*NOTREACHED*/
83 }
84 t = db_read_token();
85 if (t != tRPAREN) {
86 db_error("Syntax error\n");
87 /*NOTREACHED*/
88 }
89 return (TRUE);
90 }
91 db_unread_token(t);
92 return (FALSE);
93}
94
95boolean_t
96db_unary(valuep)
97 db_expr_t *valuep;
98{
99 int t;
100
101 t = db_read_token();
102 if (t == tMINUS) {
103 if (!db_unary(valuep)) {
104 db_error("Syntax error\n");
105 /*NOTREACHED*/
106 }
107 *valuep = -*valuep;
108 return (TRUE);
109 }
110 if (t == tSTAR) {
111 /* indirection */
112 if (!db_unary(valuep)) {
113 db_error("Syntax error\n");
114 /*NOTREACHED*/
115 }
116 *valuep = db_get_value((db_addr_t)*valuep, sizeof(int), FALSE);
117 return (TRUE);
118 }
119 db_unread_token(t);
120 return (db_term(valuep));
121}
122
123boolean_t
124db_mult_expr(valuep)
125 db_expr_t *valuep;
126{
127 db_expr_t lhs, rhs;
128 int t;
129
130 if (!db_unary(&lhs))
131 return (FALSE);
132
133 t = db_read_token();
134 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) {
135 if (!db_term(&rhs)) {
136 db_error("Syntax error\n");
137 /*NOTREACHED*/
138 }
139 if (t == tSTAR)
140 lhs *= rhs;
141 else {
142 if (rhs == 0) {
143 db_error("Divide by 0\n");
144 /*NOTREACHED*/
145 }
146 if (t == tSLASH)
147 lhs /= rhs;
148 else if (t == tPCT)
149 lhs %= rhs;
150 else
151 lhs = ((lhs+rhs-1)/rhs)*rhs;
152 }
153 t = db_read_token();
154 }
155 db_unread_token(t);
156 *valuep = lhs;
157 return (TRUE);
158}
159
160boolean_t
161db_add_expr(valuep)
162 db_expr_t *valuep;
163{
164 db_expr_t lhs, rhs;
165 int t;
166
167 if (!db_mult_expr(&lhs))
168 return (FALSE);
169
170 t = db_read_token();
171 while (t == tPLUS || t == tMINUS) {
172 if (!db_mult_expr(&rhs)) {
173 db_error("Syntax error\n");
174 /*NOTREACHED*/
175 }
176 if (t == tPLUS)
177 lhs += rhs;
178 else
179 lhs -= rhs;
180 t = db_read_token();
181 }
182 db_unread_token(t);
183 *valuep = lhs;
184 return (TRUE);
185}
186
187boolean_t
188db_shift_expr(valuep)
189 db_expr_t *valuep;
190{
191 db_expr_t lhs, rhs;
192 int t;
193
194 if (!db_add_expr(&lhs))
195 return (FALSE);
196
197 t = db_read_token();
198 while (t == tSHIFT_L || t == tSHIFT_R) {
199 if (!db_add_expr(&rhs)) {
200 db_error("Syntax error\n");
201 /*NOTREACHED*/
202 }
203 if (rhs < 0) {
204 db_error("Negative shift amount\n");
205 /*NOTREACHED*/
206 }
207 if (t == tSHIFT_L)
208 lhs <<= rhs;
209 else {
210 /* Shift right is unsigned */
211 lhs = (unsigned) lhs >> rhs;
212 }
213 t = db_read_token();
214 }
215 db_unread_token(t);
216 *valuep = lhs;
217 return (TRUE);
218}
219
220int
221db_expression(valuep)
222 db_expr_t *valuep;
223{
224 return (db_shift_expr(valuep));
225}
|