From 2e27b7f9c2081ecdc72a88948bc1083fb0012d4b Mon Sep 17 00:00:00 2001
From: FeralChild64 <you@example.com>
Date: Wed, 8 Jan 2020 19:03:28 +0100
Subject: [PATCH] further line grow fixes

---
 c64/kernal/screen/chrout_screen_ins.s        |  1 -
 c64/kernal/screen/screen_grow_logical_line.s | 33 ++++++++++++++------
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/c64/kernal/screen/chrout_screen_ins.s b/c64/kernal/screen/chrout_screen_ins.s
index 20d99a06..a51dc131 100644
--- a/c64/kernal/screen/chrout_screen_ins.s
+++ b/c64/kernal/screen/chrout_screen_ins.s
@@ -5,7 +5,6 @@
 
 
 // YYY does not work properly on growing logical line
-// YYY implement LNMX
 
 
 chrout_screen_INS:
diff --git a/c64/kernal/screen/screen_grow_logical_line.s b/c64/kernal/screen/screen_grow_logical_line.s
index 7e2627cc..e5b9e9e3 100644
--- a/c64/kernal/screen/screen_grow_logical_line.s
+++ b/c64/kernal/screen/screen_grow_logical_line.s
@@ -4,6 +4,9 @@
 screen_grow_logical_line_screen_up:
 
 	jsr screen_scroll_up
+	ldy TBLX
+	lda #$00
+	sta LDTBL+1, y                      // mark the next line as continuation
 
 	// FALLTROUGH
 
@@ -17,7 +20,7 @@ screen_grow_logical_line:
 
 	// Do not grow line if previus one is grown
 	ldy TBLX
-	lda LDTBL,y
+	lda LDTBL+0, y
 	bpl screen_grow_logical_line_done
 
 	// If last line, scroll the screen up
@@ -25,22 +28,35 @@ screen_grow_logical_line:
 	beq screen_grow_logical_line_screen_up
 
 	// Do not grow line if already grown
-	iny
-	lda LDTBL,y
+	lda LDTBL+1, y
 	bpl screen_grow_logical_line_done
 	
+	// Preserve SAL and EAL
+
+	jsr screen_preserve_sal_eal
+
+	// Scroll LDTBL down (start from the end)
+	ldy #23
+!:
+	cpy TBLX
+	beq !+
+	bcc !+
+
+	lda LDTBL+0, y
+	sta LDTBL+1, y
+
+	dey
+	bne !-
+!:
 	// Mark current line as grown
+	ldy TBLX
 	lda #$00
-	sta LDTBL,y
+	sta LDTBL+1, y
 
 	// Now we have to scroll lines downwards to make space. We start from the end,
 	// and work backwards. We cannot be as simple and efficient here as we are
 	// for scrolling up, because we do not know how much must be scrolled.
 
-	// Preserve SAL and EAL
-
-	jsr screen_preserve_sal_eal
-
 	// Work out how many physical lines to scroll down
 
 	lda #23
@@ -71,7 +87,6 @@ screen_grow_logical_line:
 screen_grow_logical_line_loop:
 
 	// Scroll down one line each loop iteration
-	// YYY add LDTBL scrolling
 
 	ldy #39
 !: