db_expr.c

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    1 /*      $NetBSD: db_expr.c,v 1.13 2002/02/15 07:33:50 simonb 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 "AS IS"
   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/cdefs.h>
   33 __KERNEL_RCSID(0, "$NetBSD: db_expr.c,v 1.13 2002/02/15 07:33:50 simonb Exp $");
   34 
   35 #include <sys/param.h>
   36 #include <sys/proc.h>
   37 
   38 #include <machine/db_machdep.h>
   39 
   40 #include <ddb/db_access.h>
   41 #include <ddb/db_command.h>
   42 #include <ddb/db_extern.h>
   43 #include <ddb/db_lex.h>
   44 #include <ddb/db_output.h>
   45 #include <ddb/db_sym.h>
   46 #include <ddb/db_variables.h>
   47 
   48 static boolean_t db_term(db_expr_t *);
   49 static boolean_t db_unary(db_expr_t *);
   50 static boolean_t db_mult_expr(db_expr_t *);
   51 static boolean_t db_add_expr(db_expr_t *);
   52 static boolean_t db_shift_expr(db_expr_t *);
   53 
   54 static boolean_t
   55 db_term(db_expr_t *valuep)
   56 {
   57         int     t;
   58 
   59         t = db_read_token();
   60         if (t == tIDENT) {
   61                 if (!db_value_of_name(db_tok_string, valuep)) {
   62                         db_expr_t v = 0;
   63                         int     i, c, byte;
   64 
   65                         /* See if we can make a number out of all of it */
   66                         for (i = 0; (c = db_tok_string[i]) != '\0'; i++) {
   67                                 byte = 0;
   68                                 if (c >= '' && c <= '9')
   69                                         byte = c - '';
   70                                 else if (db_radix == 16 && c >= 'a' && c <= 'f')
   71                                         byte = c - 'a' + 10;
   72                                 else if (db_radix == 16 && c >= 'A' && c <= 'F')
   73                                         byte = c - 'A' + 10;
   74                                 else
   75                                         db_error("Symbol not found\n");
   76                                         /*NOTREACHED*/
   77                                 v = v * db_radix + byte;
   78                         }
   79                         *valuep = (db_expr_t)v;
   80                 }
   81                 return (TRUE);
   82         }
   83         if (t == tNUMBER) {
   84                 *valuep = (db_expr_t)db_tok_number;
   85                 return (TRUE);
   86         }
   87         if (t == tDOT) {
   88                 *valuep = (db_expr_t)db_dot;
   89                 return (TRUE);
   90         }
   91         if (t == tDOTDOT) {
   92                 *valuep = (db_expr_t)db_prev;
   93                 return (TRUE);
   94         }
   95         if (t == tPLUS) {
   96                 *valuep = (db_expr_t) db_next;
   97                 return (TRUE);
   98         }
   99         if (t == tDITTO) {
  100                 *valuep = (db_expr_t)db_last_addr;
  101                 return (TRUE);
  102         }
  103         if (t == tDOLLAR) {
  104                 if (!db_get_variable(valuep))
  105                     return (FALSE);
  106                 return (TRUE);
  107         }
  108         if (t == tLPAREN) {
  109                 if (!db_expression(valuep)) {
  110                         db_error("Syntax error\n");
  111                         /*NOTREACHED*/
  112                 }
  113                 t = db_read_token();
  114                 if (t != tRPAREN) {
  115                         db_error("Syntax error\n");
  116                         /*NOTREACHED*/
  117                 }
  118                 return (TRUE);
  119         }
  120         db_unread_token(t);
  121         return (FALSE);
  122 }
  123 
  124 static boolean_t
  125 db_unary(db_expr_t *valuep)
  126 {
  127         int     t;
  128 
  129         t = db_read_token();
  130         if (t == tMINUS) {
  131                 if (!db_unary(valuep)) {
  132                         db_error("Syntax error\n");
  133                         /*NOTREACHED*/
  134                 }
  135                 *valuep = -*valuep;
  136                 return (TRUE);
  137         }
  138         if (t == tSTAR) {
  139                 /* indirection */
  140                 if (!db_unary(valuep)) {
  141                         db_error("Syntax error\n");
  142                         /*NOTREACHED*/
  143                 }
  144                 *valuep = db_get_value((db_addr_t)*valuep, sizeof(db_expr_t),
  145                     FALSE);
  146                 return (TRUE);
  147         }
  148         db_unread_token(t);
  149         return (db_term(valuep));
  150 }
  151 
  152 static boolean_t
  153 db_mult_expr(db_expr_t *valuep)
  154 {
  155         db_expr_t       lhs, rhs;
  156         int             t;
  157 
  158         if (!db_unary(&lhs))
  159                 return (FALSE);
  160 
  161         t = db_read_token();
  162         while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) {
  163                 if (!db_term(&rhs)) {
  164                         db_error("Syntax error\n");
  165                         /*NOTREACHED*/
  166                 }
  167                 if (t == tSTAR)
  168                         lhs *= rhs;
  169                 else {
  170                         if (rhs == 0) {
  171                                 db_error("Divide by 0\n");
  172                                 /*NOTREACHED*/
  173                         }
  174                         if (t == tSLASH)
  175                                 lhs /= rhs;
  176                         else if (t == tPCT)
  177                                 lhs %= rhs;
  178                         else
  179                                 lhs = ((lhs+rhs-1)/rhs)*rhs;
  180                 }
  181                 t = db_read_token();
  182         }
  183         db_unread_token(t);
  184         *valuep = lhs;
  185         return (TRUE);
  186 }
  187 
  188 static boolean_t
  189 db_add_expr(db_expr_t *valuep)
  190 {
  191         db_expr_t       lhs, rhs;
  192         int             t;
  193 
  194         if (!db_mult_expr(&lhs))
  195                 return (FALSE);
  196 
  197         t = db_read_token();
  198         while (t == tPLUS || t == tMINUS) {
  199                 if (!db_mult_expr(&rhs)) {
  200                         db_error("Syntax error\n");
  201                         /*NOTREACHED*/
  202                 }
  203                 if (t == tPLUS)
  204                         lhs += rhs;
  205                 else
  206                         lhs -= rhs;
  207                 t = db_read_token();
  208         }
  209         db_unread_token(t);
  210         *valuep = lhs;
  211         return (TRUE);
  212 }
  213 
  214 static boolean_t
  215 db_shift_expr(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 long) 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(db_expr_t *valuep)
  248 {
  249 
  250         return (db_shift_expr(valuep));
  251 }

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

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sys/ddb/db_expr.c