fix for EAL corruption

c64/kernal/screen/screen_grow_logical_line.s

@@ -36,7 +36,13 @@ count_rows_loop:
 	cpx #0
 	beq no_copy_down
 	bmi no_copy_down
-	
+
+	// Preserve EAL
+	lda EAL+0
+	pha
+	lda EAL+1
+	pha
+
 	// Set pointers to end of screen line, and one line
 	// above.  (It is always one physical line, because
 	// this can only happen when expanding a line from 40 to
@@ -105,6 +111,12 @@ cl_inner:
 	dex
 	bne copy_line_down_loop
 
+ 	// Restore EAL
+ 	pla
+ 	sta EAL+1
+ 	pla
+ 	sta EAL+0
+
 no_copy_down:
 	jsr screen_calculate_line_pointer
 

c64/kernal/screen/screen_scroll_up_if_on_last_line.s

@@ -28,6 +28,13 @@ is_last_line:
 	// FALLTHROUGH
 
 scroll_screen_up:
+
+	// Preserve EAL
+	lda EAL+0
+	pha
+	lda EAL+1
+	pha	
+
 	// Now scroll the whole screen up either one or two lines
 	// based on whether the first screen line is linked or not.
 
@@ -88,6 +95,12 @@ scroll_copy_loop2:
  	dex
  	bne scroll_copy_loop2
 
+ 	// Restore EAL
+ 	pla
+ 	sta EAL+1
+ 	pla
+ 	sta EAL+0
+
 	// Fill in scrolled up area
 	ldx SAL+0
 scroll_copy_loop3: