diff --git a/BaS_gcc/include/xhdi_sd.h b/BaS_gcc/include/xhdi_sd.h
index 973caab..d05190d 100644
--- a/BaS_gcc/include/xhdi_sd.h
+++ b/BaS_gcc/include/xhdi_sd.h
@@ -86,7 +86,7 @@ typedef void* (*xhdi_call_fun)(int xhdi_fun, ...);
 
 struct XHDICALL_args
 {
-	unsigned int opcode;
+	uint16_t opcode;
 };
 
 extern unsigned long xhdi_call(struct XHDICALL_args stack);
diff --git a/BaS_gcc/sources/xhdi_interface.c b/BaS_gcc/sources/xhdi_interface.c
index b0f150b..364b5ce 100644
--- a/BaS_gcc/sources/xhdi_interface.c
+++ b/BaS_gcc/sources/xhdi_interface.c
@@ -29,7 +29,7 @@
 
 uint32_t xhdi_call(struct XHDICALL_args stack)
 {
-	uint32_t opcode = stack.opcode;
+	uint16_t opcode = stack.opcode;
 
 	switch (opcode)
 	{