diff --git a/desktop/invoker.s b/desktop/invoker.s
index 4d6ac0c..f32467e 100644
--- a/desktop/invoker.s
+++ b/desktop/invoker.s
@@ -39,6 +39,7 @@ prefix_length:
 bs_path:
         PASCAL_STRING "BASIC.SYSTEM"
 
+        ;; $EE = extended call signature for IIgs/GS/OS variation.
         DEFINE_QUIT_PARAMS quit_params, $EE, FILENAME
 
 ;;; ============================================================
diff --git a/inc/prodos.inc b/inc/prodos.inc
index 2bff39e..e6bac61 100644
--- a/inc/prodos.inc
+++ b/inc/prodos.inc
@@ -331,16 +331,16 @@ int_num:        .byte   0
 .endproc
 .endmacro
 
-.macro DEFINE_QUIT_PARAMS name, arg1, arg2
+.macro DEFINE_QUIT_PARAMS name, ext, pathname
 .proc name
 param_count:    .byte   4
-    .ifnblank arg1
-        .byte   arg1
+    .ifnblank ext
+        .byte   ext
     .else
         .byte   0
     .endif
-    .ifnblank arg2
-        .word   arg2
+    .ifnblank pathname
+        .word   pathname
     .else
         .word   0
     .endif