1 /* $OpenBSD: db_expr.c,v 1.17 2019/11/07 13:16:25 mpi Exp $ */ 2 /* $NetBSD: db_expr.c,v 1.5 1996/02/05 01:56:58 christos Exp $ */ 3 4 /* 5 * Mach Operating System 6 * Copyright (c) 1993,1992,1991,1990 Carnegie Mellon University 7 * All Rights Reserved. 8 * 9 * Permission to use, copy, modify and distribute this software and its 10 * documentation is hereby granted, provided that both the copyright 11 * notice and this permission notice appear in all copies of the 12 * software, derivative works or modified versions, and any portions 13 * thereof, and that both notices appear in supporting documentation. 14 * 15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 16 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 17 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 18 * 19 * Carnegie Mellon requests users of this software to return to 20 * 21 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 22 * School of Computer Science 23 * Carnegie Mellon University 24 * Pittsburgh PA 15213-3890 25 * 26 * any improvements or extensions that they make and grant Carnegie Mellon 27 * the rights to redistribute these changes. 28 * 29 * Author: David B. Golub, Carnegie Mellon University 30 * Date: 7/90 31 */ 32 33 #include <sys/param.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 int db_term(db_expr_t *); 45 int db_unary(db_expr_t *); 46 int db_mult_expr(db_expr_t *); 47 int db_add_expr(db_expr_t *); 48 int db_shift_expr(db_expr_t *); 49 50 int 51 db_term(db_expr_t *valuep) 52 { 53 int t; 54 55 t = db_read_token(); 56 if (t == tIDENT) { 57 if (db_symbol_by_name(db_tok_string, valuep) == NULL) { 58 db_error("Symbol not found\n"); 59 /*NOTREACHED*/ 60 } 61 return 1; 62 } 63 if (t == tNUMBER) { 64 *valuep = db_tok_number; 65 return 1; 66 } 67 if (t == tDOT) { 68 *valuep = (db_expr_t)db_dot; 69 return 1; 70 } 71 if (t == tDOTDOT) { 72 *valuep = (db_expr_t)db_prev; 73 return 1; 74 } 75 if (t == tPLUS) { 76 *valuep = (db_expr_t) db_next; 77 return 1; 78 } 79 if (t == tDITTO) { 80 *valuep = (db_expr_t)db_last_addr; 81 return 1; 82 } 83 if (t == tDOLLAR) { 84 if (!db_get_variable(valuep)) 85 return 0; 86 return 1; 87 } 88 if (t == tLPAREN) { 89 if (!db_expression(valuep)) { 90 db_error("Syntax error\n"); 91 /*NOTREACHED*/ 92 } 93 t = db_read_token(); 94 if (t != tRPAREN) { 95 db_error("Syntax error\n"); 96 /*NOTREACHED*/ 97 } 98 return 1; 99 } 100 db_unread_token(t); 101 return 0; 102 } 103 104 int 105 db_unary(db_expr_t *valuep) 106 { 107 int t; 108 109 t = db_read_token(); 110 if (t == tMINUS) { 111 if (!db_unary(valuep)) { 112 db_error("Syntax error\n"); 113 /*NOTREACHED*/ 114 } 115 *valuep = -*valuep; 116 return 1; 117 } 118 if (t == tSTAR) { 119 /* indirection */ 120 if (!db_unary(valuep)) { 121 db_error("Syntax error\n"); 122 /*NOTREACHED*/ 123 } 124 *valuep = db_get_value((vaddr_t)*valuep, sizeof(vaddr_t), 0); 125 return 1; 126 } 127 db_unread_token(t); 128 return (db_term(valuep)); 129 } 130 131 int 132 db_mult_expr(db_expr_t *valuep) 133 { 134 db_expr_t lhs, rhs; 135 int t; 136 137 if (!db_unary(&lhs)) 138 return 0; 139 140 t = db_read_token(); 141 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) { 142 if (!db_term(&rhs)) { 143 db_error("Syntax error\n"); 144 /*NOTREACHED*/ 145 } 146 if (t == tSTAR) 147 lhs *= rhs; 148 else { 149 if (rhs == 0) { 150 db_error("Divide by 0\n"); 151 /*NOTREACHED*/ 152 } 153 if (t == tSLASH) 154 lhs /= rhs; 155 else if (t == tPCT) 156 lhs %= rhs; 157 else 158 lhs = ((lhs+rhs-1)/rhs)*rhs; 159 } 160 t = db_read_token(); 161 } 162 db_unread_token(t); 163 *valuep = lhs; 164 return 1; 165 } 166 167 int 168 db_add_expr(db_expr_t *valuep) 169 { 170 db_expr_t lhs, rhs; 171 int t; 172 173 if (!db_mult_expr(&lhs)) 174 return 0; 175 176 t = db_read_token(); 177 while (t == tPLUS || t == tMINUS) { 178 if (!db_mult_expr(&rhs)) { 179 db_error("Syntax error\n"); 180 /*NOTREACHED*/ 181 } 182 if (t == tPLUS) 183 lhs += rhs; 184 else 185 lhs -= rhs; 186 t = db_read_token(); 187 } 188 db_unread_token(t); 189 *valuep = lhs; 190 return 1; 191 } 192 193 int 194 db_shift_expr(db_expr_t *valuep) 195 { 196 db_expr_t lhs, rhs; 197 int t; 198 199 if (!db_add_expr(&lhs)) 200 return 0; 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) lhs >> rhs; 217 } 218 t = db_read_token(); 219 } 220 db_unread_token(t); 221 *valuep = lhs; 222 return 1; 223 } 224 225 int 226 db_expression(db_expr_t *valuep) 227 { 228 return (db_shift_expr(valuep)); 229 } 230