diff --git a/src/include/pc80/mc146818rtc.h b/src/include/pc80/mc146818rtc.h
index edc3241..f0d58d8 100644
--- a/src/include/pc80/mc146818rtc.h
+++ b/src/include/pc80/mc146818rtc.h
@@ -175,6 +175,10 @@
 #define CMOS_POST_BANK_0_OFFSET   (CMOS_POST_OFFSET + 1)
 #define CMOS_POST_BANK_1_MAGIC    0x81
 #define CMOS_POST_BANK_1_OFFSET   (CMOS_POST_OFFSET + 2)
+
+#if !defined(__ROMCC__)
+void cmos_post_log(void);
+#endif
 #endif /* CONFIG_CMOS_POST */
 
 #endif /*  PC80_MC146818RTC_H */