diff --git a/abstract-machine/am/src/platform/nemu/ioe/audio.c b/abstract-machine/am/src/platform/nemu/ioe/audio.c
index 34bd632..98c2478 100644
--- a/abstract-machine/am/src/platform/nemu/ioe/audio.c
+++ b/abstract-machine/am/src/platform/nemu/ioe/audio.c
@@ -38,7 +38,7 @@ void __am_audio_play(AM_AUDIO_PLAY_T *ctl) {
   int cnt = ctl->buf.end - ctl->buf.start, i = 0;
   while (cnt) {
     // lock sbuf
-    outl(AUDIO_INIT_ADDR, 1 << 1);
+    outl(AUDIO_INIT_ADDR, 2);
     for (; i < cnt; i++) {
       if (inl(AUDIO_COUNT_ADDR) == audio_sbuf_size) {
         i--;
diff --git a/nemu/src/device/audio.c b/nemu/src/device/audio.c
index e4286a2..8a43506 100644
--- a/nemu/src/device/audio.c
+++ b/nemu/src/device/audio.c
@@ -89,7 +89,7 @@ static void audio_io_handler(uint32_t offset, int len, bool is_write) {
     case reg_init:
       if (is_write) {
         if (audio_base[reg_init] & 1) init_audio_dev();
-        if (audio_base[reg_init] & 1 << 1) {
+        if (audio_base[reg_init] & 2) {
           mtx_lock(&mtx_audio);
         } else {
           mtx_unlock(&mtx_audio);