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