db_expr.c revision 1.2.4.1
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 (at) 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 * $Id: db_expr.c,v 1.2.4.1 1993/11/14 22:48:33 mycroft Exp $ 28 * 29 * HISTORY 30 * $Log: db_expr.c,v $ 31 * Revision 1.2.4.1 1993/11/14 22:48:33 mycroft 32 * Canonicalize all #includes. 33 * 34 * Revision 1.2 1993/05/20 03:39:13 cgd 35 * add explicit rcs id 36 * 37 * Revision 1.1.1.1 1993/03/21 09:46:26 cgd 38 * initial import of 386bsd-0.1 sources 39 * 40 * Revision 1.1 1992/03/25 21:45:09 pace 41 * Initial revision 42 * 43 * Revision 2.3 91/02/05 17:06:25 mrt 44 * Changed to new Mach copyright 45 * [91/01/31 16:17:46 mrt] 46 * 47 * Revision 2.2 90/08/27 21:50:57 dbg 48 * Use '..' instead of '$$' for db_prev. 49 * Use '+' for db_next. 50 * [90/08/22 dbg] 51 * 52 * Allow repeated unary operators. 53 * [90/08/20 dbg] 54 * 55 * Reflected back rename of db_symbol_value->db_value_of_name 56 * [90/08/20 af] 57 * Reduce lint. 58 * [90/08/07 dbg] 59 * Created. 60 * [90/07/25 dbg] 61 * 62 */ 63 /* 64 * Author: David B. Golub, Carnegie Mellon University 65 * Date: 7/90 66 */ 67 #include <sys/param.h> 68 #include <sys/proc.h> 69 #include <machine/db_machdep.h> 70 71 #include <ddb/db_lex.h> 72 #include <ddb/db_access.h> 73 #include <ddb/db_command.h> 74 75 boolean_t 76 db_term(valuep) 77 db_expr_t *valuep; 78 { 79 int t; 80 81 t = db_read_token(); 82 if (t == tIDENT) { 83 if (!db_value_of_name(db_tok_string, valuep)) { 84 db_error("Symbol not found\n"); 85 /*NOTREACHED*/ 86 } 87 return (TRUE); 88 } 89 if (t == tNUMBER) { 90 *valuep = (db_expr_t)db_tok_number; 91 return (TRUE); 92 } 93 if (t == tDOT) { 94 *valuep = (db_expr_t)db_dot; 95 return (TRUE); 96 } 97 if (t == tDOTDOT) { 98 *valuep = (db_expr_t)db_prev; 99 return (TRUE); 100 } 101 if (t == tPLUS) { 102 *valuep = (db_expr_t) db_next; 103 return (TRUE); 104 } 105 if (t == tDITTO) { 106 *valuep = (db_expr_t)db_last_addr; 107 return (TRUE); 108 } 109 if (t == tDOLLAR) { 110 if (!db_get_variable(valuep)) 111 return (FALSE); 112 return (TRUE); 113 } 114 if (t == tLPAREN) { 115 if (!db_expression(valuep)) { 116 db_error("Syntax error\n"); 117 /*NOTREACHED*/ 118 } 119 t = db_read_token(); 120 if (t != tRPAREN) { 121 db_error("Syntax error\n"); 122 /*NOTREACHED*/ 123 } 124 return (TRUE); 125 } 126 db_unread_token(t); 127 return (FALSE); 128 } 129 130 boolean_t 131 db_unary(valuep) 132 db_expr_t *valuep; 133 { 134 int t; 135 136 t = db_read_token(); 137 if (t == tMINUS) { 138 if (!db_unary(valuep)) { 139 db_error("Syntax error\n"); 140 /*NOTREACHED*/ 141 } 142 *valuep = -*valuep; 143 return (TRUE); 144 } 145 if (t == tSTAR) { 146 /* indirection */ 147 if (!db_unary(valuep)) { 148 db_error("Syntax error\n"); 149 /*NOTREACHED*/ 150 } 151 *valuep = db_get_value((db_addr_t)*valuep, sizeof(int), FALSE); 152 return (TRUE); 153 } 154 db_unread_token(t); 155 return (db_term(valuep)); 156 } 157 158 boolean_t 159 db_mult_expr(valuep) 160 db_expr_t *valuep; 161 { 162 db_expr_t lhs, rhs; 163 int t; 164 165 if (!db_unary(&lhs)) 166 return (FALSE); 167 168 t = db_read_token(); 169 while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) { 170 if (!db_term(&rhs)) { 171 db_error("Syntax error\n"); 172 /*NOTREACHED*/ 173 } 174 if (t == tSTAR) 175 lhs *= rhs; 176 else { 177 if (rhs == 0) { 178 db_error("Divide by 0\n"); 179 /*NOTREACHED*/ 180 } 181 if (t == tSLASH) 182 lhs /= rhs; 183 else if (t == tPCT) 184 lhs %= rhs; 185 else 186 lhs = ((lhs+rhs-1)/rhs)*rhs; 187 } 188 t = db_read_token(); 189 } 190 db_unread_token(t); 191 *valuep = lhs; 192 return (TRUE); 193 } 194 195 boolean_t 196 db_add_expr(valuep) 197 db_expr_t *valuep; 198 { 199 db_expr_t lhs, rhs; 200 int t; 201 202 if (!db_mult_expr(&lhs)) 203 return (FALSE); 204 205 t = db_read_token(); 206 while (t == tPLUS || t == tMINUS) { 207 if (!db_mult_expr(&rhs)) { 208 db_error("Syntax error\n"); 209 /*NOTREACHED*/ 210 } 211 if (t == tPLUS) 212 lhs += rhs; 213 else 214 lhs -= rhs; 215 t = db_read_token(); 216 } 217 db_unread_token(t); 218 *valuep = lhs; 219 return (TRUE); 220 } 221 222 boolean_t 223 db_shift_expr(valuep) 224 db_expr_t *valuep; 225 { 226 db_expr_t lhs, rhs; 227 int t; 228 229 if (!db_add_expr(&lhs)) 230 return (FALSE); 231 232 t = db_read_token(); 233 while (t == tSHIFT_L || t == tSHIFT_R) { 234 if (!db_add_expr(&rhs)) { 235 db_error("Syntax error\n"); 236 /*NOTREACHED*/ 237 } 238 if (rhs < 0) { 239 db_error("Negative shift amount\n"); 240 /*NOTREACHED*/ 241 } 242 if (t == tSHIFT_L) 243 lhs <<= rhs; 244 else { 245 /* Shift right is unsigned */ 246 lhs = (unsigned) lhs >> rhs; 247 } 248 t = db_read_token(); 249 } 250 db_unread_token(t); 251 *valuep = lhs; 252 return (TRUE); 253 } 254 255 int 256 db_expression(valuep) 257 db_expr_t *valuep; 258 { 259 return (db_shift_expr(valuep)); 260 } 261
Indexes created Mon Sep 29 13:09:55 GMT 2025