1 /* $NetBSD: db_expr.c,v 1.5 1996/02/05 01:56:58 christos 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 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(int), FALSE); 121 return (TRUE); 122 } 123 db_unread_token(t); 124 return (db_term(valuep)); 125 } 126 127 boolean_t 128 db_mult_expr(valuep) 129 db_expr_t *valuep; 130 { 131 db_expr_t lhs, rhs; 132 int t; 133 134 if (!db_unary(&lhs)) 135 return (FALSE); 136 137 t = db_read_token(); 138 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) { 139 if (!db_term(&rhs)) { 140 db_error("Syntax error\n"); 141 /*NOTREACHED*/ 142 } 143 if (t == tSTAR) 144 lhs *= rhs; 145 else { 146 if (rhs == 0) { 147 db_error("Divide by 0\n"); 148 /*NOTREACHED*/ 149 } 150 if (t == tSLASH) 151 lhs /= rhs; 152 else if (t == tPCT) 153 lhs %= rhs; 154 else 155 lhs = ((lhs+rhs-1)/rhs)*rhs; 156 } 157 t = db_read_token(); 158 } 159 db_unread_token(t); 160 *valuep = lhs; 161 return (TRUE); 162 } 163 164 boolean_t 165 db_add_expr(valuep) 166 db_expr_t *valuep; 167 { 168 db_expr_t lhs, rhs; 169 int t; 170 171 if (!db_mult_expr(&lhs)) 172 return (FALSE); 173 174 t = db_read_token(); 175 while (t == tPLUS || t == tMINUS) { 176 if (!db_mult_expr(&rhs)) { 177 db_error("Syntax error\n"); 178 /*NOTREACHED*/ 179 } 180 if (t == tPLUS) 181 lhs += rhs; 182 else 183 lhs -= rhs; 184 t = db_read_token(); 185 } 186 db_unread_token(t); 187 *valuep = lhs; 188 return (TRUE); 189 } 190 191 boolean_t 192 db_shift_expr(valuep) 193 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(valuep) 226 db_expr_t *valuep; 227 { 228 return (db_shift_expr(valuep)); 229 } 230