1 | /* $NetBSD: db_expr.c,v 1.16 2009/03/07 22:02:17 ad Exp $ */ |
2 | |
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 "AS IS" |
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 Software.Distribution@CS.CMU.EDU |
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 | * Author: David B. Golub, Carnegie Mellon University |
29 | * Date: 7/90 |
30 | */ |
31 | |
32 | #include <sys/cdefs.h> |
33 | __KERNEL_RCSID(0, "$NetBSD: db_expr.c,v 1.16 2009/03/07 22:02:17 ad Exp $" ); |
34 | |
35 | #include <sys/param.h> |
36 | #include <sys/proc.h> |
37 | |
38 | #include <ddb/ddb.h> |
39 | |
40 | static bool db_term(db_expr_t *); |
41 | static bool db_unary(db_expr_t *); |
42 | static bool db_mult_expr(db_expr_t *); |
43 | static bool db_add_expr(db_expr_t *); |
44 | static bool db_shift_expr(db_expr_t *); |
45 | |
46 | static bool |
47 | db_term(db_expr_t *valuep) |
48 | { |
49 | int t; |
50 | |
51 | t = db_read_token(); |
52 | if (t == tIDENT) { |
53 | if (!db_value_of_name(db_tok_string, valuep)) { |
54 | db_expr_t v = 0; |
55 | int i, c, byte; |
56 | |
57 | /* See if we can make a number out of all of it */ |
58 | for (i = 0; (c = db_tok_string[i]) != '\0'; i++) { |
59 | byte = 0; |
60 | if (c >= '0' && c <= '9') |
61 | byte = c - '0'; |
62 | else if (db_radix == 16 && c >= 'a' && c <= 'f') |
63 | byte = c - 'a' + 10; |
64 | else if (db_radix == 16 && c >= 'A' && c <= 'F') |
65 | byte = c - 'A' + 10; |
66 | else |
67 | db_error("Symbol not found\n" ); |
68 | /*NOTREACHED*/ |
69 | v = v * db_radix + byte; |
70 | } |
71 | *valuep = (db_expr_t)v; |
72 | } |
73 | return (true); |
74 | } |
75 | if (t == tNUMBER) { |
76 | *valuep = (db_expr_t)db_tok_number; |
77 | return (true); |
78 | } |
79 | if (t == tDOT) { |
80 | *valuep = (db_expr_t)db_dot; |
81 | return (true); |
82 | } |
83 | if (t == tDOTDOT) { |
84 | *valuep = (db_expr_t)db_prev; |
85 | return (true); |
86 | } |
87 | if (t == tPLUS) { |
88 | *valuep = (db_expr_t) db_next; |
89 | return (true); |
90 | } |
91 | if (t == tDITTO) { |
92 | *valuep = (db_expr_t)db_last_addr; |
93 | return (true); |
94 | } |
95 | if (t == tDOLLAR) { |
96 | if (!db_get_variable(valuep)) |
97 | return (false); |
98 | return (true); |
99 | } |
100 | if (t == tLPAREN) { |
101 | if (!db_expression(valuep)) { |
102 | db_error("Syntax error\n" ); |
103 | /*NOTREACHED*/ |
104 | } |
105 | t = db_read_token(); |
106 | if (t != tRPAREN) { |
107 | db_error("Syntax error\n" ); |
108 | /*NOTREACHED*/ |
109 | } |
110 | return (true); |
111 | } |
112 | db_unread_token(t); |
113 | return (false); |
114 | } |
115 | |
116 | static bool |
117 | db_unary(db_expr_t *valuep) |
118 | { |
119 | int t; |
120 | |
121 | t = db_read_token(); |
122 | if (t == tMINUS) { |
123 | if (!db_unary(valuep)) { |
124 | db_error("Syntax error\n" ); |
125 | /*NOTREACHED*/ |
126 | } |
127 | *valuep = -*valuep; |
128 | return (true); |
129 | } |
130 | if (t == tSTAR) { |
131 | /* indirection */ |
132 | if (!db_unary(valuep)) { |
133 | db_error("Syntax error\n" ); |
134 | /*NOTREACHED*/ |
135 | } |
136 | *valuep = db_get_value((db_addr_t)*valuep, sizeof(db_expr_t), |
137 | false); |
138 | return (true); |
139 | } |
140 | db_unread_token(t); |
141 | return (db_term(valuep)); |
142 | } |
143 | |
144 | static bool |
145 | db_mult_expr(db_expr_t *valuep) |
146 | { |
147 | db_expr_t lhs, rhs; |
148 | int t; |
149 | |
150 | if (!db_unary(&lhs)) |
151 | return (false); |
152 | |
153 | t = db_read_token(); |
154 | while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) { |
155 | if (!db_term(&rhs)) { |
156 | db_error("Syntax error\n" ); |
157 | /*NOTREACHED*/ |
158 | } |
159 | if (t == tSTAR) |
160 | lhs *= rhs; |
161 | else { |
162 | if (rhs == 0) { |
163 | db_error("Divide by 0\n" ); |
164 | /*NOTREACHED*/ |
165 | } |
166 | if (t == tSLASH) |
167 | lhs /= rhs; |
168 | else if (t == tPCT) |
169 | lhs %= rhs; |
170 | else |
171 | lhs = ((lhs+rhs-1)/rhs)*rhs; |
172 | } |
173 | t = db_read_token(); |
174 | } |
175 | db_unread_token(t); |
176 | *valuep = lhs; |
177 | return (true); |
178 | } |
179 | |
180 | static bool |
181 | db_add_expr(db_expr_t *valuep) |
182 | { |
183 | db_expr_t lhs, rhs; |
184 | int t; |
185 | |
186 | if (!db_mult_expr(&lhs)) |
187 | return (false); |
188 | |
189 | t = db_read_token(); |
190 | while (t == tPLUS || t == tMINUS) { |
191 | if (!db_mult_expr(&rhs)) { |
192 | db_error("Syntax error\n" ); |
193 | /*NOTREACHED*/ |
194 | } |
195 | if (t == tPLUS) |
196 | lhs += rhs; |
197 | else |
198 | lhs -= rhs; |
199 | t = db_read_token(); |
200 | } |
201 | db_unread_token(t); |
202 | *valuep = lhs; |
203 | return (true); |
204 | } |
205 | |
206 | static bool |
207 | db_shift_expr(db_expr_t *valuep) |
208 | { |
209 | db_expr_t lhs, rhs; |
210 | int t; |
211 | |
212 | if (!db_add_expr(&lhs)) |
213 | return (false); |
214 | |
215 | t = db_read_token(); |
216 | while (t == tSHIFT_L || t == tSHIFT_R) { |
217 | if (!db_add_expr(&rhs)) { |
218 | db_error("Syntax error\n" ); |
219 | /*NOTREACHED*/ |
220 | } |
221 | if (rhs < 0) { |
222 | db_error("Negative shift amount\n" ); |
223 | /*NOTREACHED*/ |
224 | } |
225 | if (t == tSHIFT_L) |
226 | lhs <<= rhs; |
227 | else { |
228 | /* Shift right is unsigned */ |
229 | lhs = (unsigned long) lhs >> rhs; |
230 | } |
231 | t = db_read_token(); |
232 | } |
233 | db_unread_token(t); |
234 | *valuep = lhs; |
235 | return (true); |
236 | } |
237 | |
238 | int |
239 | db_expression(db_expr_t *valuep) |
240 | { |
241 | |
242 | return (db_shift_expr(valuep)); |
243 | } |
244 | |