1 /* $NetBSD: db_expr.c,v 1.9 1999/04/12 20:38:21 pk 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/param.h> 33 #include <sys/proc.h> 34 35 #include <machine/db_machdep.h> 36 37 #include <ddb/db_lex.h> 38 #include <ddb/db_access.h> 39 #include <ddb/db_command.h> 40 #include <ddb/db_sym.h> 41 #include <ddb/db_extern.h> 42 #include <ddb/db_variables.h> 43 44 boolean_t 45 db_term(valuep) 46 db_expr_t *valuep; 47 { 48 int t; 49 50 t = db_read_token(); 51 if (t == tIDENT) { 52 if (!db_value_of_name(db_tok_string, valuep)) { 53 db_error("Symbol not found\n"); 54 /*NOTREACHED*/ 55 } 56 return (TRUE); 57 } 58 if (t == tNUMBER) { 59 *valuep = (db_expr_t)db_tok_number; 60 return (TRUE); 61 } 62 if (t == tDOT) { 63 *valuep = (db_expr_t)db_dot; 64 return (TRUE); 65 } 66 if (t == tDOTDOT) { 67 *valuep = (db_expr_t)db_prev; 68 return (TRUE); 69 } 70 if (t == tPLUS) { 71 *valuep = (db_expr_t) db_next; 72 return (TRUE); 73 } 74 if (t == tDITTO) { 75 *valuep = (db_expr_t)db_last_addr; 76 return (TRUE); 77 } 78 if (t == tDOLLAR) { 79 if (!db_get_variable(valuep)) 80 return (FALSE); 81 return (TRUE); 82 } 83 if (t == tLPAREN) { 84 if (!db_expression(valuep)) { 85 db_error("Syntax error\n"); 86 /*NOTREACHED*/ 87 } 88 t = db_read_token(); 89 if (t != tRPAREN) { 90 db_error("Syntax error\n"); 91 /*NOTREACHED*/ 92 } 93 return (TRUE); 94 } 95 db_unread_token(t); 96 return (FALSE); 97 } 98 99 boolean_t 100 db_unary(valuep) 101 db_expr_t *valuep; 102 { 103 int t; 104 105 t = db_read_token(); 106 if (t == tMINUS) { 107 if (!db_unary(valuep)) { 108 db_error("Syntax error\n"); 109 /*NOTREACHED*/ 110 } 111 *valuep = -*valuep; 112 return (TRUE); 113 } 114 if (t == tSTAR) { 115 /* indirection */ 116 if (!db_unary(valuep)) { 117 db_error("Syntax error\n"); 118 /*NOTREACHED*/ 119 } 120 *valuep = db_get_value((db_addr_t)*valuep, sizeof(db_expr_t), 121 FALSE); 122 return (TRUE); 123 } 124 db_unread_token(t); 125 return (db_term(valuep)); 126 } 127 128 boolean_t 129 db_mult_expr(valuep) 130 db_expr_t *valuep; 131 { 132 db_expr_t lhs, rhs; 133 int t; 134 135 if (!db_unary(&lhs)) 136 return (FALSE); 137 138 t = db_read_token(); 139 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) { 140 if (!db_term(&rhs)) { 141 db_error("Syntax error\n"); 142 /*NOTREACHED*/ 143 } 144 if (t == tSTAR) 145 lhs *= rhs; 146 else { 147 if (rhs == 0) { 148 db_error("Divide by 0\n"); 149 /*NOTREACHED*/ 150 } 151 if (t == tSLASH) 152 lhs /= rhs; 153 else if (t == tPCT) 154 lhs %= rhs; 155 else 156 lhs = ((lhs+rhs-1)/rhs)*rhs; 157 } 158 t = db_read_token(); 159 } 160 db_unread_token(t); 161 *valuep = lhs; 162 return (TRUE); 163 } 164 165 boolean_t 166 db_add_expr(valuep) 167 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 boolean_t 193 db_shift_expr(valuep) 194 db_expr_t *valuep; 195 { 196 db_expr_t lhs, rhs; 197 int t; 198 199 if (!db_add_expr(&lhs)) 200 return (FALSE); 201 202 t = db_read_token(); 203 while (t == tSHIFT_L || t == tSHIFT_R) { 204 if (!db_add_expr(&rhs)) { 205 db_error("Syntax error\n"); 206 /*NOTREACHED*/ 207 } 208 if (rhs < 0) { 209 db_error("Negative shift amount\n"); 210 /*NOTREACHED*/ 211 } 212 if (t == tSHIFT_L) 213 lhs <<= rhs; 214 else { 215 /* Shift right is unsigned */ 216 lhs = (unsigned long) lhs >> rhs; 217 } 218 t = db_read_token(); 219 } 220 db_unread_token(t); 221 *valuep = lhs; 222 return (TRUE); 223 } 224 225 int 226 db_expression(valuep) 227 db_expr_t *valuep; 228 { 229 return (db_shift_expr(valuep)); 230 } 231