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 * Author: David B. Golub, Carnegie Mellon University 28 * Date: 7/90 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 36 #include <ddb/ddb.h> 37 #include <ddb/db_lex.h> 38 #include <ddb/db_access.h> 39 #include <ddb/db_command.h> 40 41 static bool db_add_expr(db_expr_t *valuep); 42 static bool db_mult_expr(db_expr_t *valuep); 43 static bool db_shift_expr(db_expr_t *valuep); 44 static bool db_term(db_expr_t *valuep); 45 static bool db_unary(db_expr_t *valuep); 46 47 static bool 48 db_term(db_expr_t *valuep) 49 { 50 int t; 51 52 t = db_read_token(); 53 if (t == tIDENT) { 54 if (!db_value_of_name(db_tok_string, valuep) && 55 !db_value_of_name_pcpu(db_tok_string, valuep) && 56 !db_value_of_name_vnet(db_tok_string, valuep)) { 57 db_error("Symbol not found\n"); 58 /*NOTREACHED*/ 59 } 60 return (true); 61 } 62 if (t == tNUMBER) { 63 *valuep = (db_expr_t)db_tok_number; 64 return (true); 65 } 66 if (t == tDOT) { 67 *valuep = (db_expr_t)db_dot; 68 return (true); 69 } 70 if (t == tDOTDOT) { 71 *valuep = (db_expr_t)db_prev; 72 return (true); 73 } 74 if (t == tPLUS) { 75 *valuep = (db_expr_t) db_next; 76 return (true); 77 } 78 if (t == tDITTO) { 79 *valuep = (db_expr_t)db_last_addr; 80 return (true); 81 } 82 if (t == tDOLLAR) { 83 if (!db_get_variable(valuep)) 84 return (false); 85 return (true); 86 } 87 if (t == tLPAREN) { 88 if (!db_expression(valuep)) { 89 db_error("Syntax error\n"); 90 /*NOTREACHED*/ 91 } 92 t = db_read_token(); 93 if (t != tRPAREN) { 94 db_error("Syntax error\n"); 95 /*NOTREACHED*/ 96 } 97 return (true); 98 } 99 db_unread_token(t); 100 return (false); 101 } 102 103 static bool 104 db_unary(db_expr_t *valuep) 105 { 106 int t; 107 108 t = db_read_token(); 109 if (t == tMINUS) { 110 if (!db_unary(valuep)) { 111 db_error("Syntax error\n"); 112 /*NOTREACHED*/ 113 } 114 *valuep = -*valuep; 115 return (true); 116 } 117 if (t == tSTAR) { 118 /* indirection */ 119 if (!db_unary(valuep)) { 120 db_error("Syntax error\n"); 121 /*NOTREACHED*/ 122 } 123 *valuep = db_get_value((db_addr_t)*valuep, sizeof(void *), false); 124 return (true); 125 } 126 db_unread_token(t); 127 return (db_term(valuep)); 128 } 129 130 static bool 131 db_mult_expr(db_expr_t *valuep) 132 { 133 db_expr_t lhs, rhs; 134 int t; 135 136 if (!db_unary(&lhs)) 137 return (false); 138 139 t = db_read_token(); 140 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) { 141 if (!db_term(&rhs)) { 142 db_error("Syntax error\n"); 143 /*NOTREACHED*/ 144 } 145 if (t == tSTAR) 146 lhs *= rhs; 147 else { 148 if (rhs == 0) { 149 db_error("Divide by 0\n"); 150 /*NOTREACHED*/ 151 } 152 if (t == tSLASH) 153 lhs /= rhs; 154 else if (t == tPCT) 155 lhs %= rhs; 156 else 157 lhs = ((lhs+rhs-1)/rhs)*rhs; 158 } 159 t = db_read_token(); 160 } 161 db_unread_token(t); 162 *valuep = lhs; 163 return (true); 164 } 165 166 static bool 167 db_add_expr(db_expr_t *valuep) 168 { 169 db_expr_t lhs, rhs; 170 int t; 171 172 if (!db_mult_expr(&lhs)) 173 return (false); 174 175 t = db_read_token(); 176 while (t == tPLUS || t == tMINUS) { 177 if (!db_mult_expr(&rhs)) { 178 db_error("Syntax error\n"); 179 /*NOTREACHED*/ 180 } 181 if (t == tPLUS) 182 lhs += rhs; 183 else 184 lhs -= rhs; 185 t = db_read_token(); 186 } 187 db_unread_token(t); 188 *valuep = lhs; 189 return (true); 190 } 191 192 static bool 193 db_shift_expr(db_expr_t *valuep) 194 { 195 db_expr_t lhs, rhs; 196 int t; 197 198 if (!db_add_expr(&lhs)) 199 return (false); 200 201 t = db_read_token(); 202 while (t == tSHIFT_L || t == tSHIFT_R) { 203 if (!db_add_expr(&rhs)) { 204 db_error("Syntax error\n"); 205 /*NOTREACHED*/ 206 } 207 if (rhs < 0) { 208 db_error("Negative shift amount\n"); 209 /*NOTREACHED*/ 210 } 211 if (t == tSHIFT_L) 212 lhs <<= rhs; 213 else { 214 /* Shift right is unsigned */ 215 lhs = (unsigned) lhs >> rhs; 216 } 217 t = db_read_token(); 218 } 219 db_unread_token(t); 220 *valuep = lhs; 221 return (true); 222 } 223 224 int 225 db_expression(db_expr_t *valuep) 226 { 227 return (db_shift_expr(valuep)); 228 } 229