diff --git a/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c b/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c
index 90bafd6..b5f6336 100644
--- a/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c
+++ b/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c
@@ -71,12 +71,13 @@
 
     #include <stdio.h>
     #include <stdlib.h>
+    #include <stdint.h>
     extern int yylex(void);
     void yyerror(const char *s) {
         fprintf(stderr, "Error: %s\n", s);
     }
 
-#line 80 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 81 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
 
 # ifndef YY_CAST
 #  ifdef __cplusplus
@@ -505,8 +506,8 @@ static const yytype_int8 yytranslate[] =
 /* YYRLINE[YYN] -- Source line where rule number YYN was defined.  */
 static const yytype_int8 yyrline[] =
 {
-       0,    15,    15,    19,    20,    21,    25,    26,    27,    31,
-      32,    33,    34
+       0,    17,    17,    21,    22,    23,    27,    28,    29,    33,
+      34,    35,    36
 };
 #endif
 
@@ -1074,73 +1075,73 @@ yyreduce:
   switch (yyn)
     {
   case 2: /* input: expression  */
-#line 15 "src/monitor/sdb/addrexp.y"
+#line 17 "src/monitor/sdb/addrexp.y"
                  { printf("Final Result: %d\n", yyvsp[0]); }
-#line 1080 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1081 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 3: /* expression: term  */
-#line 19 "src/monitor/sdb/addrexp.y"
+#line 21 "src/monitor/sdb/addrexp.y"
            { yyval = yyvsp[0]; }
-#line 1086 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1087 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 4: /* expression: expression '+' term  */
-#line 20 "src/monitor/sdb/addrexp.y"
+#line 22 "src/monitor/sdb/addrexp.y"
                            { yyval = yyvsp[-2] + yyvsp[0]; }
-#line 1092 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1093 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 5: /* expression: expression '-' term  */
-#line 21 "src/monitor/sdb/addrexp.y"
+#line 23 "src/monitor/sdb/addrexp.y"
                            { yyval = yyvsp[-2] - yyvsp[0]; }
-#line 1098 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1099 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 6: /* term: factor  */
-#line 25 "src/monitor/sdb/addrexp.y"
+#line 27 "src/monitor/sdb/addrexp.y"
              { yyval = yyvsp[0]; }
-#line 1104 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1105 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 7: /* term: term '*' factor  */
-#line 26 "src/monitor/sdb/addrexp.y"
+#line 28 "src/monitor/sdb/addrexp.y"
                        { yyval = yyvsp[-2] * yyvsp[0]; }
-#line 1110 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1111 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 8: /* term: term '/' factor  */
-#line 27 "src/monitor/sdb/addrexp.y"
+#line 29 "src/monitor/sdb/addrexp.y"
                        { yyval = yyvsp[-2] / yyvsp[0]; }
-#line 1116 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1117 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 9: /* factor: NUMBER  */
-#line 31 "src/monitor/sdb/addrexp.y"
+#line 33 "src/monitor/sdb/addrexp.y"
              { yyval = yyvsp[0]; }
-#line 1122 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1123 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 10: /* factor: HEX_NUMBER  */
-#line 32 "src/monitor/sdb/addrexp.y"
+#line 34 "src/monitor/sdb/addrexp.y"
                  { yyval = yyvsp[0]; }
-#line 1128 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1129 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 11: /* factor: '-' factor  */
-#line 33 "src/monitor/sdb/addrexp.y"
+#line 35 "src/monitor/sdb/addrexp.y"
                  { yyval = -yyvsp[0]; }
-#line 1134 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1135 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
   case 12: /* factor: '(' expression ')'  */
-#line 34 "src/monitor/sdb/addrexp.y"
+#line 36 "src/monitor/sdb/addrexp.y"
                          { yyval = yyvsp[-1]; }
-#line 1140 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1141 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
     break;
 
 
-#line 1144 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
+#line 1145 "/home/xin/repo/ysyx-workbench/nemu/build/obj-riscv32-nemu-interpreter/src/monitor/sdb/addrexp.tag.c"
 
       default: break;
     }
@@ -1333,5 +1334,5 @@ yyreturnlab:
   return yyresult;
 }
 
-#line 37 "src/monitor/sdb/addrexp.y"
+#line 39 "src/monitor/sdb/addrexp.y"
 
diff --git a/nemu/scripts/build.mk b/nemu/scripts/build.mk
index 3cd172f..776b4cd 100644
--- a/nemu/scripts/build.mk
+++ b/nemu/scripts/build.mk
@@ -45,17 +45,17 @@ $(OBJ_DIR)/%.tag.c: %.y
 	@mkdir -p $(dir $@)
 	@$(YACC) $(YFLAGS) --header=$(<:.y=.h) -o $@ $<
 
+$(OBJ_DIR)/%.yy.c: %.l $(OBJ_DIR)/%.tag.c
+	@echo + LEX $<
+	@mkdir -p $(dir $@)
+	@$(LEX) $(LFLAGS) -o $@ $<
+
 $(OBJ_DIR)/%.tag.o: $(OBJ_DIR)/%.tag.c
 	@echo + CC $<
 	@mkdir -p $(dir $@)
 	@$(CC) $(CFLAGS) -c -o $@ $<
 	$(call call_fixdep, $(@:.o=.d), $@)
 
-$(OBJ_DIR)/%.yy.c: %.l $(OBJ_DIR)/%.tag.c
-	@echo + LEX $<
-	@mkdir -p $(dir $@)
-	@$(LEX) $(LFLAGS) -o $@ $<
-
 $(OBJ_DIR)/%.yy.o: $(OBJ_DIR)/%.yy.c
 	@echo + CC $<
 	@mkdir -p $(dir $@)
diff --git a/nemu/src/monitor/sdb/addrexp.h b/nemu/src/monitor/sdb/addrexp.h
index b5310c4..cfd5e1e 100644
--- a/nemu/src/monitor/sdb/addrexp.h
+++ b/nemu/src/monitor/sdb/addrexp.h
@@ -69,7 +69,7 @@ extern int yydebug;
 
 /* Value type.  */
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
-typedef int YYSTYPE;
+typedef  uint32_t  YYSTYPE;
 # define YYSTYPE_IS_TRIVIAL 1
 # define YYSTYPE_IS_DECLARED 1
 #endif
diff --git a/nemu/src/monitor/sdb/sdb.c b/nemu/src/monitor/sdb/sdb.c
index 23218d5..dffb84d 100644
--- a/nemu/src/monitor/sdb/sdb.c
+++ b/nemu/src/monitor/sdb/sdb.c
@@ -326,8 +326,8 @@ void sdb_mainloop() {
 }
 
 void init_sdb() {
-  /* Compile the regular expressions. */
-  init_regex();
+  // /* Compile the regular expressions. */
+  // init_regex();
 
   /* Initialize the watchpoint pool. */
   init_wp_pool();