diff --git a/abstract-machine/am/src/platform/nemu/ioe/audio.c b/abstract-machine/am/src/platform/nemu/ioe/audio.c
index b99f971..97dd06e 100644
--- a/abstract-machine/am/src/platform/nemu/ioe/audio.c
+++ b/abstract-machine/am/src/platform/nemu/ioe/audio.c
@@ -8,8 +8,8 @@
 #define AUDIO_INIT_ADDR      (AUDIO_ADDR + 0x10)
 #define AUDIO_COUNT_ADDR     (AUDIO_ADDR + 0x14)
 
-static size_t audio_write = 0;
-static size_t audio_sbuf_size;
+static uint32_t audio_write = 0;
+static uint32_t audio_sbuf_size;
 
 void __am_audio_init() {
 }