--- a/packages/hal/mips/vrc437x/current/include/hal_diag.h
+++ b/packages/hal/mips/vrc437x/current/include/hal_diag.h
@@ -49,6 +49,16 @@
 
 #include <cyg/infra/cyg_type.h>
 
+#if defined(CYGSEM_HAL_VIRTUAL_VECTOR_DIAG)
+
+#include <cyg/hal/hal_if.h>
+
+#define HAL_DIAG_INIT() hal_if_diag_init()
+#define HAL_DIAG_WRITE_CHAR(_c_) hal_if_diag_write_char(_c_)
+#define HAL_DIAG_READ_CHAR(_c_) hal_if_diag_read_char(&_c_)
+
+#else // everything by steam
+
 /*---------------------------------------------------------------------------*/
 /* functions implemented in hal_diag.c                                       */
 
@@ -66,6 +76,8 @@ externC void hal_diag_read_char(char *c)
 
 #define HAL_DIAG_READ_CHAR(_c_) hal_diag_read_char(&_c_)
 
+#endif
+
 /*---------------------------------------------------------------------------*/
 /* end of hal_diag.h                                                         */
 #endif /* CYGONCE_HAL_HAL_DIAG_H */