From eed50e63f483a2141f5a36f275a0faf1eaaf9ac4 Mon Sep 17 00:00:00 2001
From: Paul Gardner-Stephen <paul@servalproject.org>
Date: Mon, 22 Apr 2019 00:39:29 +0930
Subject: [PATCH] fix bug when expanding last line on screen

---
 c64/kernal/chrout.s | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/c64/kernal/chrout.s b/c64/kernal/chrout.s
index 6d016134..50c60df1 100644
--- a/c64/kernal/chrout.s
+++ b/c64/kernal/chrout.s
@@ -225,6 +225,10 @@ count_rows_loop:
 *	iny
 	cpy current_screen_y
 	bne count_rows_loop
+
+	stx $0420
+	cpx #0
+	beq no_copy_down
 	
 	;; Set pointers to end of screen line, and one line
 	;; above.  (It is always one physical line, because
@@ -293,6 +297,7 @@ cl_inner:
 	dex
 	bne copy_line_down_loop
 
+no_copy_down:	
 	jsr calculate_screen_line_pointer
 
 	;; Erase newly inserted line