db_expr.c revision 189581
1239462Sdim/*- 2234285Sdim * Mach Operating System 3234285Sdim * Copyright (c) 1991,1990 Carnegie Mellon University 4234285Sdim * All Rights Reserved. 5234285Sdim * 6234285Sdim * Permission to use, copy, modify and distribute this software and its 7234285Sdim * documentation is hereby granted, provided that both the copyright 8234285Sdim * notice and this permission notice appear in all copies of the 9234285Sdim * software, derivative works or modified versions, and any portions 10234285Sdim * thereof, and that both notices appear in supporting documentation. 11234285Sdim * 12234285Sdim * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 13234285Sdim * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 14234285Sdim * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 15249423Sdim * 16234285Sdim * Carnegie Mellon requests users of this software to return to 17249423Sdim * 18249423Sdim * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 19249423Sdim * School of Computer Science 20234285Sdim * Carnegie Mellon University 21234285Sdim * Pittsburgh PA 15213-3890 22234285Sdim * 23234285Sdim * any improvements or extensions that they make and grant Carnegie the 24251662Sdim * rights to redistribute these changes. 25251662Sdim */ 26251662Sdim/* 27251662Sdim * Author: David B. Golub, Carnegie Mellon University 28251662Sdim * Date: 7/90 29234285Sdim */ 30234285Sdim 31234285Sdim#include <sys/cdefs.h> 32234285Sdim__FBSDID("$FreeBSD: head/sys/ddb/db_expr.c 189581 2009-03-09 13:32:19Z imp $"); 33251662Sdim 34251662Sdim#include <sys/param.h> 35251662Sdim 36234285Sdim#include <ddb/ddb.h> 37234285Sdim#include <ddb/db_lex.h> 38234285Sdim#include <ddb/db_access.h> 39234285Sdim#include <ddb/db_command.h> 40234285Sdim 41234285Sdimstatic boolean_t db_add_expr(db_expr_t *valuep); 42234285Sdimstatic boolean_t db_mult_expr(db_expr_t *valuep); 43234285Sdimstatic boolean_t db_shift_expr(db_expr_t *valuep); 44234285Sdimstatic boolean_t db_term(db_expr_t *valuep); 45234285Sdimstatic boolean_t db_unary(db_expr_t *valuep); 46234285Sdim 47234285Sdimstatic boolean_t 48234285Sdimdb_term(db_expr_t *valuep) 49234285Sdim{ 50234285Sdim int t; 51234285Sdim 52251662Sdim t = db_read_token(); 53251662Sdim if (t == tIDENT) { 54234285Sdim if (!db_value_of_name(db_tok_string, valuep)) { 55234285Sdim db_error("Symbol not found\n"); 56234285Sdim /*NOTREACHED*/ 57234285Sdim } 58234285Sdim return (TRUE); 59249423Sdim } 60234285Sdim if (t == tNUMBER) { 61234285Sdim *valuep = (db_expr_t)db_tok_number; 62234285Sdim return (TRUE); 63234285Sdim } 64234285Sdim if (t == tDOT) { 65234285Sdim *valuep = (db_expr_t)db_dot; 66234285Sdim return (TRUE); 67234285Sdim } 68234285Sdim if (t == tDOTDOT) { 69234285Sdim *valuep = (db_expr_t)db_prev; 70234285Sdim return (TRUE); 71234285Sdim } 72234285Sdim if (t == tPLUS) { 73234285Sdim *valuep = (db_expr_t) db_next; 74234285Sdim return (TRUE); 75234285Sdim } 76234285Sdim if (t == tDITTO) { 77234285Sdim *valuep = (db_expr_t)db_last_addr; 78234285Sdim return (TRUE); 79234285Sdim } 80234285Sdim if (t == tDOLLAR) { 81234285Sdim if (!db_get_variable(valuep)) 82234285Sdim return (FALSE); 83234285Sdim return (TRUE); 84234285Sdim } 85234285Sdim if (t == tLPAREN) { 86251662Sdim if (!db_expression(valuep)) { 87251662Sdim db_error("Syntax error\n"); 88234285Sdim /*NOTREACHED*/ 89234285Sdim } 90 t = db_read_token(); 91 if (t != tRPAREN) { 92 db_error("Syntax error\n"); 93 /*NOTREACHED*/ 94 } 95 return (TRUE); 96 } 97 db_unread_token(t); 98 return (FALSE); 99} 100 101static boolean_t 102db_unary(db_expr_t *valuep) 103{ 104 int t; 105 106 t = db_read_token(); 107 if (t == tMINUS) { 108 if (!db_unary(valuep)) { 109 db_error("Syntax error\n"); 110 /*NOTREACHED*/ 111 } 112 *valuep = -*valuep; 113 return (TRUE); 114 } 115 if (t == tSTAR) { 116 /* indirection */ 117 if (!db_unary(valuep)) { 118 db_error("Syntax error\n"); 119 /*NOTREACHED*/ 120 } 121 *valuep = db_get_value((db_addr_t)*valuep, sizeof(void *), FALSE); 122 return (TRUE); 123 } 124 db_unread_token(t); 125 return (db_term(valuep)); 126} 127 128static boolean_t 129db_mult_expr(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 164static boolean_t 165db_add_expr(db_expr_t *valuep) 166{ 167 db_expr_t lhs, rhs; 168 int t; 169 170 if (!db_mult_expr(&lhs)) 171 return (FALSE); 172 173 t = db_read_token(); 174 while (t == tPLUS || t == tMINUS) { 175 if (!db_mult_expr(&rhs)) { 176 db_error("Syntax error\n"); 177 /*NOTREACHED*/ 178 } 179 if (t == tPLUS) 180 lhs += rhs; 181 else 182 lhs -= rhs; 183 t = db_read_token(); 184 } 185 db_unread_token(t); 186 *valuep = lhs; 187 return (TRUE); 188} 189 190static boolean_t 191db_shift_expr(db_expr_t *valuep) 192{ 193 db_expr_t lhs, rhs; 194 int t; 195 196 if (!db_add_expr(&lhs)) 197 return (FALSE); 198 199 t = db_read_token(); 200 while (t == tSHIFT_L || t == tSHIFT_R) { 201 if (!db_add_expr(&rhs)) { 202 db_error("Syntax error\n"); 203 /*NOTREACHED*/ 204 } 205 if (rhs < 0) { 206 db_error("Negative shift amount\n"); 207 /*NOTREACHED*/ 208 } 209 if (t == tSHIFT_L) 210 lhs <<= rhs; 211 else { 212 /* Shift right is unsigned */ 213 lhs = (unsigned) lhs >> rhs; 214 } 215 t = db_read_token(); 216 } 217 db_unread_token(t); 218 *valuep = lhs; 219 return (TRUE); 220} 221 222int 223db_expression(db_expr_t *valuep) 224{ 225 return (db_shift_expr(valuep)); 226} 227