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
31 *
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 *
51 */
52/*
53 * Author: David B. Golub, Carnegie Mellon University
54 * Date: 7/90
55 */
56#include "param.h"
57#include "proc.h"
58#include <machine/db_machdep.h>
59#include <ddb/db_lex.h>
60#include <ddb/db_access.h>
61#include <ddb/db_command.h>
62
63boolean_t
64db_term(valuep)
65 db_expr_t *valuep;
66{
67 int t;
68
69 t = db_read_token();
70 if (t == tIDENT) {
71 if (!db_value_of_name(db_tok_string, valuep)) {
72 db_error("Symbol not found\n");
73 /*NOTREACHED*/
74 }
75 return (TRUE);
76 }
77 if (t == tNUMBER) {
78 *valuep = (db_expr_t)db_tok_number;
79 return (TRUE);
80 }
81 if (t == tDOT) {
82 *valuep = (db_expr_t)db_dot;
83 return (TRUE);
84 }
85 if (t == tDOTDOT) {
86 *valuep = (db_expr_t)db_prev;
87 return (TRUE);
88 }
89 if (t == tPLUS) {
90 *valuep = (db_expr_t) db_next;
91 return (TRUE);
92 }
93 if (t == tDITTO) {
94 *valuep = (db_expr_t)db_last_addr;
95 return (TRUE);
96 }
97 if (t == tDOLLAR) {
98 if (!db_get_variable(valuep))
99 return (FALSE);
100 return (TRUE);
101 }
102 if (t == tLPAREN) {
103 if (!db_expression(valuep)) {
104 db_error("Syntax error\n");
105 /*NOTREACHED*/
106 }
107 t = db_read_token();
108 if (t != tRPAREN) {
109 db_error("Syntax error\n");
110 /*NOTREACHED*/
111 }
112 return (TRUE);
113 }
114 db_unread_token(t);
115 return (FALSE);
116}
117
118boolean_t
119db_unary(valuep)
120 db_expr_t *valuep;
121{
122 int t;
123
124 t = db_read_token();
125 if (t == tMINUS) {
126 if (!db_unary(valuep)) {
127 db_error("Syntax error\n");
128 /*NOTREACHED*/
129 }
130 *valuep = -*valuep;
131 return (TRUE);
132 }
133 if (t == tSTAR) {
134 /* indirection */
135 if (!db_unary(valuep)) {
136 db_error("Syntax error\n");
137 /*NOTREACHED*/
138 }
139 *valuep = db_get_value((db_addr_t)*valuep, sizeof(int), FALSE);
140 return (TRUE);
141 }
142 db_unread_token(t);
143 return (db_term(valuep));
144}
145
146boolean_t
147db_mult_expr(valuep)
148 db_expr_t *valuep;
149{
150 db_expr_t lhs, rhs;
151 int t;
152
153 if (!db_unary(&lhs))
154 return (FALSE);
155
156 t = db_read_token();
157 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) {
158 if (!db_term(&rhs)) {
159 db_error("Syntax error\n");
160 /*NOTREACHED*/
161 }
162 if (t == tSTAR)
163 lhs *= rhs;
164 else {
165 if (rhs == 0) {
166 db_error("Divide by 0\n");
167 /*NOTREACHED*/
168 }
169 if (t == tSLASH)
170 lhs /= rhs;
171 else if (t == tPCT)
172 lhs %= rhs;
173 else
174 lhs = ((lhs+rhs-1)/rhs)*rhs;
175 }
176 t = db_read_token();
177 }
178 db_unread_token(t);
179 *valuep = lhs;
180 return (TRUE);
181}
182
183boolean_t
184db_add_expr(valuep)
185 db_expr_t *valuep;
186{
187 db_expr_t lhs, rhs;
188 int t;
189
190 if (!db_mult_expr(&lhs))
191 return (FALSE);
192
193 t = db_read_token();
194 while (t == tPLUS || t == tMINUS) {
195 if (!db_mult_expr(&rhs)) {
196 db_error("Syntax error\n");
197 /*NOTREACHED*/
198 }
199 if (t == tPLUS)
200 lhs += rhs;
201 else
202 lhs -= rhs;
203 t = db_read_token();
204 }
205 db_unread_token(t);
206 *valuep = lhs;
207 return (TRUE);
208}
209
210boolean_t
211db_shift_expr(valuep)
212 db_expr_t *valuep;
213{
214 db_expr_t lhs, rhs;
215 int t;
216
217 if (!db_add_expr(&lhs))
218 return (FALSE);
219
220 t = db_read_token();
221 while (t == tSHIFT_L || t == tSHIFT_R) {
222 if (!db_add_expr(&rhs)) {
223 db_error("Syntax error\n");
224 /*NOTREACHED*/
225 }
226 if (rhs < 0) {
227 db_error("Negative shift amount\n");
228 /*NOTREACHED*/
229 }
230 if (t == tSHIFT_L)
231 lhs <<= rhs;
232 else {
233 /* Shift right is unsigned */
234 lhs = (unsigned) lhs >> rhs;
235 }
236 t = db_read_token();
237 }
238 db_unread_token(t);
239 *valuep = lhs;
240 return (TRUE);
241}
242
243int
244db_expression(valuep)
245 db_expr_t *valuep;
246{
247 return (db_shift_expr(valuep));
248}