don't allow IRQs during CHROUT to avoid all cursor pooh

c64/kernal/blink_cursor.s

@@ -78,7 +78,7 @@ no_blink_cursor:
 	rts
 
 disable_cursor:
-	lda #$ff
+	lda #$80
 	sta cursor_blink_disable
 	;; FALL THROUGH
 hide_cursor_if_visible:

c64/kernal/chrout.s

@@ -11,6 +11,8 @@ chrout:
 	pha
 	tya
 	pha
+	php
+	sei
 	
 	jsr hide_cursor_if_visible
 	
@@ -372,6 +374,8 @@ no_screen_advance_to_next_line:
 chrout_done:
 	jsr show_cursor_if_enabled
 	
+	plp
+	
 	;; Restore X and Y, set carry to mark success on exit
 	pla
 	tay