1 /*-
2 * SPDX-License-Identifier: MIT-CMU
3 *
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
15 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 * Software Distribution Coordinator or [email protected]
21 * School of Computer Science
22 * Carnegie Mellon University
23 * Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28 /*
29 * Author: David B. Golub, Carnegie Mellon University
30 * Date: 7/90
31 */
32
33 #include <sys/cdefs.h>
34 #include <sys/param.h>
35 #include <sys/systm.h>
36
37 #include <ddb/ddb.h>
38 #include <ddb/db_lex.h>
39 #include <ddb/db_access.h>
40 #include <ddb/db_command.h>
41
42 static bool db_add_expr(db_expr_t *valuep);
43 static bool db_mult_expr(db_expr_t *valuep);
44 static bool db_shift_expr(db_expr_t *valuep);
45 static bool db_term(db_expr_t *valuep);
46 static bool db_unary(db_expr_t *valuep);
47 static bool db_logical_or_expr(db_expr_t *valuep);
48 static bool db_logical_and_expr(db_expr_t *valuep);
49 static bool db_logical_relation_expr(db_expr_t *valuep);
50
51 static bool
db_term(db_expr_t * valuep)52 db_term(db_expr_t *valuep)
53 {
54 int t;
55
56 t = db_read_token();
57 if (t == tIDENT) {
58 if (!db_value_of_name(db_tok_string, valuep) &&
59 !db_value_of_name_pcpu(db_tok_string, valuep) &&
60 !db_value_of_name_vnet(db_tok_string, valuep)) {
61 db_printf("Symbol '%s' not found\n", db_tok_string);
62 db_error(NULL);
63 /*NOTREACHED*/
64 }
65 return (true);
66 }
67 if (t == tNUMBER) {
68 *valuep = (db_expr_t)db_tok_number;
69 return (true);
70 }
71 if (t == tDOT) {
72 *valuep = (db_expr_t)db_dot;
73 return (true);
74 }
75 if (t == tDOTDOT) {
76 *valuep = (db_expr_t)db_prev;
77 return (true);
78 }
79 if (t == tPLUS) {
80 *valuep = (db_expr_t) db_next;
81 return (true);
82 }
83 if (t == tDITTO) {
84 *valuep = (db_expr_t)db_last_addr;
85 return (true);
86 }
87 if (t == tDOLLAR) {
88 if (!db_get_variable(valuep))
89 return (false);
90 return (true);
91 }
92 if (t == tLPAREN) {
93 if (!db_expression(valuep)) {
94 db_printf("Expression syntax error after '%c'\n", '(');
95 db_error(NULL);
96 /*NOTREACHED*/
97 }
98 t = db_read_token();
99 if (t != tRPAREN) {
100 db_printf("Expression syntax error -- expected '%c'\n", ')');
101 db_error(NULL);
102 /*NOTREACHED*/
103 }
104 return (true);
105 }
106 db_unread_token(t);
107 return (false);
108 }
109
110 static bool
db_unary(db_expr_t * valuep)111 db_unary(db_expr_t *valuep)
112 {
113 int t;
114
115 t = db_read_token();
116 if (t == tMINUS) {
117 if (!db_unary(valuep)) {
118 db_printf("Expression syntax error after '%c'\n", '-');
119 db_error(NULL);
120 /*NOTREACHED*/
121 }
122 *valuep = -*valuep;
123 return (true);
124 }
125 if (t == tEXCL) {
126 if (!db_unary(valuep)) {
127 db_printf("Expression syntax error after '%c'\n", '!');
128 db_error(NULL);
129 /* NOTREACHED */
130 }
131 *valuep = (!(*valuep));
132 return (true);
133 }
134 if (t == tBIT_NOT) {
135 if (!db_unary(valuep)) {
136 db_printf("Expression syntax error after '%c'\n", '~');
137 db_error(NULL);
138 /* NOTREACHED */
139 }
140 *valuep = (~(*valuep));
141 return (true);
142 }
143 if (t == tSTAR) {
144 /* indirection */
145 if (!db_unary(valuep)) {
146 db_printf("Expression syntax error after '%c'\n", '*');
147 db_error(NULL);
148 /*NOTREACHED*/
149 }
150 *valuep = db_get_value((db_addr_t)*valuep, sizeof(void *),
151 false);
152 return (true);
153 }
154 db_unread_token(t);
155 return (db_term(valuep));
156 }
157
158 static bool
db_mult_expr(db_expr_t * valuep)159 db_mult_expr(db_expr_t *valuep)
160 {
161 db_expr_t lhs, rhs;
162 int t;
163
164 if (!db_unary(&lhs))
165 return (false);
166
167 t = db_read_token();
168 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH ||
169 t == tBIT_AND ) {
170 if (!db_term(&rhs)) {
171 db_printf("Expression syntax error after '%c'\n",
172 t == tSTAR ? '*' : t == tSLASH ? '/' : t == tPCT ? '%' :
173 t == tHASH ? '#' : '&');
174 db_error(NULL);
175 /*NOTREACHED*/
176 }
177 switch(t) {
178 case tSTAR:
179 lhs *= rhs;
180 break;
181 case tBIT_AND:
182 lhs &= rhs;
183 break;
184 default:
185 if (rhs == 0) {
186 db_error("Division by 0\n");
187 /*NOTREACHED*/
188 }
189 if (t == tSLASH)
190 lhs /= rhs;
191 else if (t == tPCT)
192 lhs %= rhs;
193 else
194 lhs = roundup(lhs, rhs);
195 }
196 t = db_read_token();
197 }
198 db_unread_token(t);
199 *valuep = lhs;
200 return (true);
201 }
202
203 static bool
db_add_expr(db_expr_t * valuep)204 db_add_expr(db_expr_t *valuep)
205 {
206 db_expr_t lhs, rhs;
207 int t;
208
209 if (!db_mult_expr(&lhs))
210 return (false);
211
212 t = db_read_token();
213 while (t == tPLUS || t == tMINUS || t == tBIT_OR) {
214 if (!db_mult_expr(&rhs)) {
215 db_printf("Expression syntax error after '%c'\n",
216 t == tPLUS ? '+' : t == tMINUS ? '-' : '|');
217 db_error(NULL);
218 /*NOTREACHED*/
219 }
220 switch (t) {
221 case tPLUS:
222 lhs += rhs;
223 break;
224 case tMINUS:
225 lhs -= rhs;
226 break;
227 case tBIT_OR:
228 lhs |= rhs;
229 break;
230 default:
231 __assert_unreachable();
232 }
233 t = db_read_token();
234 }
235 db_unread_token(t);
236 *valuep = lhs;
237 return (true);
238 }
239
240 static bool
db_shift_expr(db_expr_t * valuep)241 db_shift_expr(db_expr_t *valuep)
242 {
243 db_expr_t lhs, rhs;
244 int t;
245
246 if (!db_add_expr(&lhs))
247 return (false);
248 t = db_read_token();
249 while (t == tSHIFT_L || t == tSHIFT_R) {
250 if (!db_add_expr(&rhs)) {
251 db_printf("Expression syntax error after '%s'\n",
252 t == tSHIFT_L ? "<<" : ">>");
253 db_error(NULL);
254 /*NOTREACHED*/
255 }
256 if (rhs < 0) {
257 db_printf("Negative shift amount %jd\n", (intmax_t)rhs);
258 db_error(NULL);
259 /*NOTREACHED*/
260 }
261 if (t == tSHIFT_L)
262 lhs <<= rhs;
263 else {
264 /* Shift right is unsigned */
265 lhs = (db_addr_t)lhs >> rhs;
266 }
267 t = db_read_token();
268 }
269 db_unread_token(t);
270 *valuep = lhs;
271 return (true);
272 }
273
274 static bool
db_logical_relation_expr(db_expr_t * valuep)275 db_logical_relation_expr(
276 db_expr_t *valuep)
277 {
278 db_expr_t lhs, rhs;
279 int t;
280
281 if (!db_shift_expr(&lhs))
282 return (false);
283
284 t = db_read_token();
285 while (t == tLOG_EQ || t == tLOG_NOT_EQ || t == tGREATER ||
286 t == tGREATER_EQ || t == tLESS || t == tLESS_EQ) {
287 if (!db_shift_expr(&rhs)) {
288 db_printf("Expression syntax error after '%s'\n",
289 t == tLOG_EQ ? "==" : t == tLOG_NOT_EQ ? "!=" :
290 t == tGREATER ? ">" : t == tGREATER_EQ ? ">=" :
291 t == tLESS ? "<" : "<=");
292 db_error(NULL);
293 /*NOTREACHED*/
294 }
295 switch(t) {
296 case tLOG_EQ:
297 lhs = (lhs == rhs);
298 break;
299 case tLOG_NOT_EQ:
300 lhs = (lhs != rhs);
301 break;
302 case tGREATER:
303 lhs = (lhs > rhs);
304 break;
305 case tGREATER_EQ:
306 lhs = (lhs >= rhs);
307 break;
308 case tLESS:
309 lhs = (lhs < rhs);
310 break;
311 case tLESS_EQ:
312 lhs = (lhs <= rhs);
313 break;
314 default:
315 __assert_unreachable();
316 }
317 t = db_read_token();
318 }
319 db_unread_token(t);
320 *valuep = lhs;
321 return (true);
322 }
323
324 static bool
db_logical_and_expr(db_expr_t * valuep)325 db_logical_and_expr(
326 db_expr_t *valuep)
327 {
328 db_expr_t lhs, rhs;
329 int t;
330
331 if (!db_logical_relation_expr(&lhs))
332 return (false);
333
334 t = db_read_token();
335 while (t == tLOG_AND) {
336 if (!db_logical_relation_expr(&rhs)) {
337 db_printf("Expression syntax error after '%s'\n", "&&");
338 db_error(NULL);
339 /*NOTREACHED*/
340 }
341 lhs = (lhs && rhs);
342 t = db_read_token();
343 }
344 db_unread_token(t);
345 *valuep = lhs;
346 return (true);
347 }
348
349 static bool
db_logical_or_expr(db_expr_t * valuep)350 db_logical_or_expr(
351 db_expr_t *valuep)
352 {
353 db_expr_t lhs, rhs;
354 int t;
355
356 if (!db_logical_and_expr(&lhs))
357 return(false);
358
359 t = db_read_token();
360 while (t == tLOG_OR) {
361 if (!db_logical_and_expr(&rhs)) {
362 db_printf("Expression syntax error after '%s'\n", "||");
363 db_error(NULL);
364 /*NOTREACHED*/
365 }
366 lhs = (lhs || rhs);
367 t = db_read_token();
368 }
369 db_unread_token(t);
370 *valuep = lhs;
371 return (true);
372 }
373
374 int
db_expression(db_expr_t * valuep)375 db_expression(db_expr_t *valuep)
376 {
377 return (db_logical_or_expr(valuep));
378 }
379