From 7f38158fa47c8d94d23f391af7a43fccde19c5b0 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vincent.weaver@maine.edu>
Date: Mon, 29 Oct 2018 12:30:09 -0400
Subject: [PATCH] megadamo: learn that we can add asserts

---
 megademo/takeoff.s   | 16 +++++++++++-----
 megademo/waterfall.s |  6 ++++--
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/megademo/takeoff.s b/megademo/takeoff.s
index e050a45c..b4c62a2b 100644
--- a/megademo/takeoff.s
+++ b/megademo/takeoff.s
@@ -137,18 +137,24 @@ toloopB:dex								; 2
 
 
 to_begin_loop:
+	; 12*4 = 48 lines of HIRES = 3120
+	;                              -4 set HIRES
+	;			    -1038 play_music
+	;			=========
+	;			     2078
 
 	bit	HIRES			; 4
 
-	; 3116 - 1038 (music) = 2078
-
-	jsr	play_music
+;	jsr	play_music	; 6 + 1032
 
 	; Try X=5 Y=67 cycles=2078
 	; Try X=11 Y=51 cycles=3112 R4
 
-	ldy	#67							; 2
-toloop8:ldx	#5							; 2
+	nop
+	nop
+
+	ldy	#51							; 2
+toloop8:ldx	#11							; 2
 toloop9:dex								; 2
 	bne	toloop9							; 2nt/3
 	dey								; 2
diff --git a/megademo/waterfall.s b/megademo/waterfall.s
index 8aa5e2ff..68181fc1 100644
--- a/megademo/waterfall.s
+++ b/megademo/waterfall.s
@@ -366,7 +366,7 @@ adjust_xpos:
 	jmp	wf_display_loop				; 3
 
 
-
+.align $100
 
 	;=========================================================
 	; fast copy rows 22-36 from $C00 to $400
@@ -374,6 +374,8 @@ adjust_xpos:
 	;
 	; 7+ 8*[9*7 + 7] + 5 = 572
 
+.assert         >gr_copy_row22 = >gr_copy_row_done, error, "gr_copy_row22 crosses page"
+
 gr_copy_row22:
 	ldy	#8							; 2
 	ldx	XPOS							; 3
@@ -399,7 +401,7 @@ grcr_loop:
 	bne	grcr_loop						; 3
 									; -1
 	rts								; 6
-
+gr_copy_row_done: