diff --git a/nemu/include/debug.h b/nemu/include/debug.h
index f60e6f9..835f8dc 100644
--- a/nemu/include/debug.h
+++ b/nemu/include/debug.h
@@ -48,4 +48,6 @@
 
 #define TODO() panic("please implement me")
 
+
+
 #endif
diff --git a/nemu/src/cpu/cpu-exec.c b/nemu/src/cpu/cpu-exec.c
index 0c244ea..e91b4c8 100644
--- a/nemu/src/cpu/cpu-exec.c
+++ b/nemu/src/cpu/cpu-exec.c
@@ -31,6 +31,7 @@ static uint64_t g_timer = 0; // unit: us
 static bool g_print_step = false;
 
 void device_update();
+void wp_eval_all();
 
 static void trace_and_difftest(Decode *_this, vaddr_t dnpc) {
 #ifdef CONFIG_ITRACE_COND
@@ -113,6 +114,8 @@ void cpu_exec(uint64_t n) {
   uint64_t timer_end = get_time();
   g_timer += timer_end - timer_start;
 
+  wp_eval_all();
+
   switch (nemu_state.state) {
     case NEMU_RUNNING: nemu_state.state = NEMU_STOP; break;
 
diff --git a/nemu/src/monitor/sdb/watchpoint.c b/nemu/src/monitor/sdb/watchpoint.c
index f84bed8..cbe1b74 100644
--- a/nemu/src/monitor/sdb/watchpoint.c
+++ b/nemu/src/monitor/sdb/watchpoint.c
@@ -13,8 +13,8 @@
  * See the Mulan PSL v2 for more details.
  ***************************************************************************************/
 
-#include "common.h"
 #include "sdb.h"
+#include <common.h>
 #include <stdio.h>
 
 #define NR_WP 32
@@ -27,8 +27,8 @@ typedef struct watchpoint {
 } WP;
 
 static WP wp_pool[NR_WP] = {};
-static WP *head = NULL, *tail = NULL, *free_ = NULL;
-static int wp_count = 0;
+static WP *head = NULL, *free_ = NULL;
+// static int wp_count = 0;
 
 void init_wp_pool() {
   int i;
@@ -41,77 +41,87 @@ void init_wp_pool() {
   free_ = wp_pool;
 }
 
-WP *wp_new() {
-  if (free_ == NULL) {
-    Error("wp_pool: Watchpoint pool not initialized or is full.");
-    return NULL;
-  }
+// static WP *wp_new() {
+//   if (free_ == NULL) {
+//     Error("wp_pool: Watchpoint pool not initialized or is full.");
+//     return NULL;
+//   }
   
-  WP *ret = free_;
-  free_ = free_->next;
+//   WP *ret = free_;
+//   free_ = free_->next;
 
-  ret->NO = 0;
-  ret->next = NULL;
-  return ret;
-}
-
-void wp_delete(WP *wp) {
-  assert(wp);
-  wp->next = free_;
-  free_ = wp;
-}
-
-int wp_add(char * expr) {
-  WP *wp = wp_new();
-  if (wp == NULL) {
-    Error("watchpoint: Failed to add watchpoint, pool is full.");
-    return 1;
-  }
-
-  wp->NO = wp_count++;
-  if (tail == NULL) {
-    head = wp;
-    tail = wp;
-  } else {
-    tail->next = wp;
-    tail = wp;
-  }
-  return 0;
-}
-
-int wp_remove_by_number(int number) {
-  WP *target_prev;
-  // Find previous node of target number
-  for (target_prev = head; target_prev != NULL && target_prev->next->NO != number; target_prev = target_prev->next) ;
-  if (target_prev == NULL) {
-    Error("Watchpoint not found, you can check current watchpoints with `info w`");
-    return 1;
-  }
-  WP *target = target_prev->next;
-  target_prev->next = target->next;
-  if (target == head) {
-    head = target->next;
-  } else if (target == tail) {
-    tail = target_prev;
-  }
-  wp_delete(target);
-  return 0;
-}
-
-// int wp_eval(WP* wp) {
-//   bool success = false;
-//   word_t result;
-
-//   result = parse_expr(wp->expr, &success);
-//   if (!success) {
-    
-//   } 
+//   ret->NO = 0;
+//   ret->next = NULL;
+//   return ret;
 // }
 
+// static void wp_delete(WP *wp) {
+//   assert(wp);
+//   wp->next = free_;
+//   free_ = wp;
+// }
+
+// static int wp_add(char * expr) {
+//   WP *wp = wp_new();
+//   if (wp == NULL) {
+//     Error("watchpoint: Failed to add watchpoint, pool is full.");
+//     return 1;
+//   }
+
+//   wp->NO = wp_count++;
+//   if (tail == NULL) {
+//     head = wp;
+//     tail = wp;
+//   } else {
+//     tail->next = wp;
+//     tail = wp;
+//   }
+//   return 0;
+// }
+
+// static int wp_remove_by_number(int number) {
+//   WP *target_prev;
+//   // Find previous node of target number
+//   for (target_prev = head; target_prev != NULL && target_prev->next->NO != number; target_prev = target_prev->next) ;
+//   if (target_prev == NULL) {
+//     Error("Watchpoint not found, you can check current watchpoints with `info w`");
+//     return 1;
+//   }
+//   WP *target = target_prev->next;
+//   target_prev->next = target->next;
+//   if (target == head) {
+//     head = target->next;
+//   } else if (target == tail) {
+//     tail = target_prev;
+//   }
+//   wp_delete(target);
+//   return 0;
+// }
+
+static bool wp_check_change(WP* wp) {
+  bool success = false;
+  word_t result;
+
+  result = parse_expr(wp->expr, &success);
+  if (!success) {
+    panic("Failed to evaluate %s", wp->expr);
+  } 
+  if (result != wp->val) {
+    wp->val = result;
+    return true;
+  }
+  return false;
+}
+
 /* 
   Check if watchpoint value changed after execution
 */
-// int wp_eval_all() {
-// }
-
-/* TODO: Implement the functionality of watchpoint */
+void wp_eval_all() {
+  WP *wp;
+  for (wp = head; wp != NULL; wp = wp->next) {
+    int prev_val = wp->val;
+    if (wp_check_change(wp)) {
+      printf("Watchpoint %d: %s\n  %u -> %u\n", wp->NO, wp->expr, prev_val, wp->val);
+    }
+  }
+}