db_expr.c

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    1 /*      $OpenBSD: db_expr.c,v 1.18 2020/10/15 03:14:00 deraadt 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 }

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FreeBSD/Linux Kernel Cross Reference sys/ddb/db_expr.c

FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_expr.c