> compile NEMU

221220000 张三
Linux zzy 5.15.146.1-microsoft-standard-WSL2 #1 SMP Thu Jan 11 04:09:03 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
 13:13:10 up 1 day, 12:03,  1 user,  load average: 0.41, 0.23, 0.13

nemu/Kconfig

@@ -1,5 +1,14 @@
 mainmenu "NEMU Configuration Menu"
 
+menu "NEMU Configuration Options"
+  config CONFIG_WATCHPOINT
+    bool "Enable Watchpoint"
+    default n
+    help
+      Say Y here if you want to enable watchpoint functionality.
+      This will add performance overhead but is useful for debugging.
+endmenu
+
 choice
   prompt "Base ISA"
   default ISA_riscv

nemu/src/cpu/cpu-exec.c

@@ -38,6 +38,15 @@ static void trace_and_difftest(Decode *_this, vaddr_t dnpc) {
 #endif
   if (g_print_step) { IFDEF(CONFIG_ITRACE, puts(_this->logbuf)); }
   IFDEF(CONFIG_DIFFTEST, difftest_step(_this->pc, dnpc));
+
+#ifdef CONFIG_WATCHPOINT
+  bool wp_check_hit(void);
+  if (wp_check_hit()) {
+    printf("watchpoint hit\n");
+    isa_reg_display();
+    nemu_state.state = NEMU_STOP;
+  }
+#endif
 }
 
 static void exec_once(Decode *s, vaddr_t pc) {

nemu/src/monitor/sdb/expr.c

@@ -42,21 +42,21 @@ static struct rule {
   int token_type;
 } rules[] = {
 
-  {" +", TK_NOTYPE},    // spaces
-  {"\\+", '+'},         // plus
-  {"==", TK_EQ},        // equal
-  {"\\!=", TK_NEQ},       // not equal
-  {"\\&\\&", TK_AND},       // and
+  {" +", TK_NOTYPE},              // spaces
+  {"\\+", '+'},                   // plus
+  {"==", TK_EQ},                  // equal
+  {"\\!=", TK_NEQ},               // not equal
+  {"\\&\\&", TK_AND},             // and
 
-  {"-", '-'},           // sub
-  {"\\*", '*'},         // mul
-  {"/", '/'},           // div
-  {"\\(", '('},         // (
-  {"\\)", ')'},         // )
+  {"-", '-'},                     // sub
+  {"\\*", '*'},                   // mul
+  {"/", '/'},                     // div
+  {"\\(", '('},                   // (
+  {"\\)", ')'},                   // )
 
-  {"0[xX][0-9a-fA-F]+", TK_HEX}, // hex number
-  {"[0-9]+", TK_DEC},   // dec number
-  {"\\$[0-9a-z]+", TK_REG},     // register
+  {"0[xX][0-9a-fA-F]+", TK_HEX},  // hex number
+  {"[0-9]+", TK_DEC},             // dec number
+  {"\\$[0-9a-z]+", TK_REG},       // register
 };
 
 #define NR_REGEX ARRLEN(rules)
@@ -266,8 +266,8 @@ uint32_t eval(const Token* arr, int p, int q, bool* success) {
     case TK_EQ: return val_l == val_r;
     case TK_NEQ: return val_l != val_r;
     case TK_AND: return val_l && val_r;
-    case '+': return val_l + val_r;
-    case '-': return val_l - val_r;
+    case '+': return (uint32_t)val_l + (uint32_t)val_r;
+    case '-': return (uint32_t)val_l - (uint32_t)val_r;
     case '*': return val_l * val_r;
     case '/': return val_l / val_r;
     default: *success &= false; return 0;

nemu/src/monitor/sdb/sdb.c

@@ -90,12 +90,14 @@ static int cmd_x(char *args) {
   char *arg0 = strtok(NULL, " ");
   char *arg1 = strtok(NULL, " ");
   if (arg0 == NULL || arg1 == NULL) {
-    goto END;
+    goto ERROR;
   }
 
   vaddr_t addr = 0;
-  if (!sscanf(arg1, FMT_PADDR, &addr)) {
-    goto END;
+  bool success = true;
+  expr(arg1, &success);
+  if (!success) {
+    goto ERROR;
   }
 
   size_t N = atoi(arg0);
@@ -106,7 +108,7 @@ static int cmd_x(char *args) {
     addr += 4;
   }
   return 0;
-END:
+ERROR:
   p_help("x");
   return 0;
 }
@@ -119,12 +121,50 @@ static int cmd_p(char *args) {
   } else {
     printf("Invalid expression\n");
   }
-  return success;
+  return !success;
 }
 
-static int cmd_w(char *args) { return 0; }
 
-static int cmd_d(char *args) { return 0; }
+typedef void WP;
+WP* new_wp(char* expr, int len);
+WP* get_wp(int NO);
+void free_wp(WP* wp);
+static int cmd_w(char *args) {
+  char*arg = strtok(NULL, " ");
+  if (arg == NULL) {
+    goto ERROR;
+  }
+  if (new_wp(arg, strlen(arg)) != NULL) {
+    printf("Watchpoint Set Failure\n");
+    goto ERROR;
+  }
+  return 0;
+ERROR:
+  p_help("w");
+  return 1;
+}
+
+static int cmd_d(char *args) {
+  char* arg = strtok(NULL, " ");
+  if (arg == NULL) {
+    goto ERROR;
+  }
+  int number = atoi(arg);
+  if (number == 0 && arg[0] != '0') {
+    printf("Invalid watchpoint number\n");
+    goto ERROR;
+  }
+  WP* wp = get_wp(number);
+  if (wp == NULL) {
+    printf("No such watchpoint\n");
+    goto ERROR;
+  }
+  free_wp(wp);
+  return 0;
+ERROR:
+  p_help("d");
+  return 1;
+}
 
 static struct {
   const char *name;

nemu/src/monitor/sdb/watchpoint.c

@@ -18,11 +18,13 @@
 #define NR_WP 32
 
 typedef struct watchpoint {
+  struct watchpoint *next; // can use WP** to access the next element
   int NO;
-  struct watchpoint *next;
 
   /* TODO: Add more members if necessary */
-
+  word_t val;
+  bool hit;
+  char expr[65532];
 } WP;
 
 static WP wp_pool[NR_WP] = {};
@@ -33,6 +35,9 @@ void init_wp_pool() {
   for (i = 0; i < NR_WP; i ++) {
     wp_pool[i].NO = i;
     wp_pool[i].next = (i == NR_WP - 1 ? NULL : &wp_pool[i + 1]);
+
+    wp_pool[i].hit = false;
+    wp_pool[i].expr[0] = '\0';
   }
 
   head = NULL;
@@ -41,3 +46,65 @@ void init_wp_pool() {
 
 /* TODO: Implement the functionality of watchpoint */
 
+bool wp_check_hit(void) {
+  bool res = false;
+  for (WP* tmp = head; tmp != NULL; tmp = tmp->next) {
+    bool success = true;
+    word_t val = expr(tmp->expr, &success);
+    assert(success);
+    if (val != tmp->val) {
+      tmp->hit = true;
+      tmp->val = val;
+      res = true;
+    }
+  }
+  return res;
+}
+
+static WP* del_wp(WP* head, WP* pos) {
+  for (WP** i = &head; (*i) != NULL && (*i)->next != NULL; i = (WP**)*i) {
+    if ((**i).NO == pos->NO) {
+      WP* res = *i;
+      *i = (**i).next;
+      return res;
+    }
+  }
+  return NULL;
+}
+
+#define MIN(x, y) ((x) < (y) ? (x) : (y))
+
+WP* new_wp(char* _expr, int len) {
+  bool success = true;
+  word_t val = expr(_expr, &success);
+  if (!success) {
+    return NULL;
+  }
+  WP* wp = del_wp(free_, free_);
+  if (wp == NULL) {
+    assert(0);
+  }
+  wp->next = head;
+  head = wp;
+  strncpy(wp->expr, _expr, MIN(sizeof(wp->expr), len));
+  wp->val = val;
+  return head;
+}
+
+WP* get_wp(int NO) {
+  for (WP* tmp = head; tmp != NULL; tmp = tmp->next) {
+    if (tmp->NO == NO) {
+      return tmp;
+    }
+  }
+  return NULL;
+}
+
+void free_wp(WP *_wp) {
+  WP* wp = del_wp(head, _wp);
+  wp->next = free_;
+  free_ = wp;
+  wp->expr[0] = '\0';
+  wp->hit = false;
+  wp->val = 0;
+}