| 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 | |