diff --git a/12_day/timer.c b/12_day/timer.c
index 0f384d6..77ad20c 100644
--- a/12_day/timer.c
+++ b/12_day/timer.c
@@ -49,7 +49,7 @@ void timer_init(struct TIMER *timer, struct FIFO8 *fifo, unsigned char data)
 
 void timer_settime(struct TIMER *timer, unsigned int timeout)
 {
-	timer->timeout = timeout;
+	timer->timeout = timeout + timerctl.count;
 	timer->flags = TIMER_FLAGS_USING;
 	return;
 }
@@ -61,8 +61,7 @@ void inthandler20(int *esp)
 	timerctl.count++;
 	for (i = 0; i < MAX_TIMER; i++) {
 		if (timerctl.timer[i].flags == TIMER_FLAGS_USING) {
-			timerctl.timer[i].timeout--;
-			if (timerctl.timer[i].timeout == 0) {
+			if (timerctl.timer[i].timeout <= timerctl.count) {
 				timerctl.timer[i].flags = TIMER_FLAGS_ALLOC;
 				fifo8_put(timerctl.timer[i].fifo, timerctl.timer[i].data);
 			}