From 960339242d33836c7af72962e85049ffae6b4757 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vincent.weaver@maine.edu>
Date: Wed, 31 May 2023 17:06:35 -0400
Subject: [PATCH] sb: fix up scroll intro

---
 games/sb/Makefile          |  2 +-
 games/sb/hardware.inc      | 11 ++---
 games/sb/hgr_logo_scroll.s | 88 ++++++++++++++++++++++++++++++++++++++
 games/sb/purple.s          |  5 +--
 games/sb/title.s           | 14 +++---
 5 files changed, 106 insertions(+), 14 deletions(-)
 create mode 100644 games/sb/hgr_logo_scroll.s

diff --git a/games/sb/Makefile b/games/sb/Makefile
index 65c860c0..d75bfeaf 100644
--- a/games/sb/Makefile
+++ b/games/sb/Makefile
@@ -78,7 +78,7 @@ TITLE:	title.o
 
 title.o:	title.s zx02_optim.s \
 		zp.inc hardware.inc \
-		hgr_vscroll.s audio.s \
+		hgr_logo_scroll.s audio.s \
 		purple.s lc_detect.s \
 		sound/purple.btc.zx02 \
 		graphics/czmg4ap_title.hgr.zx02 \
diff --git a/games/sb/hardware.inc b/games/sb/hardware.inc
index 83a10a6c..bcc421c4 100644
--- a/games/sb/hardware.inc
+++ b/games/sb/hardware.inc
@@ -23,12 +23,13 @@ PADDLE_BUTTON0	=	$C061
 PADDL0		=	$C064
 PTRIG		=	$C070
 
-;; BASIC ROUTINES
-
-NORMAL	=	$F273
-
-;; MONITOR ROUTINES
+;=================
+; ROM ROUTINES
+;=================
+; note we can't use these if language card RAM switched in
 
+NORMAL	= $F273
+HGR	= $F3E2
 HLINE	= $F819			;; HLINE Y,$2C at A
 VLINE	= $F828			;; VLINE A,$2D at Y
 CLRSCR	= $F832			;; Clear low-res screen
diff --git a/games/sb/hgr_logo_scroll.s b/games/sb/hgr_logo_scroll.s
new file mode 100644
index 00000000..31cb4e5b
--- /dev/null
+++ b/games/sb/hgr_logo_scroll.s
@@ -0,0 +1,88 @@
+	;================================
+	; HGR vscroll
+	;================================
+	; image to scroll in is in $4000
+	;
+
+hgr_vscroll:
+
+	ldx	#191						; 2
+	stx	SCROLL		; SCROLL = 0			; 3
+
+vscroll_loop:
+
+	;====================
+	; draw bottom part
+
+	lda	#0						; 2
+	sta	SCROLL_OFFSET		; offset in logo	; 3
+	ldx	SCROLL			; offset in screen	; 3
+vscroll_bottom:
+
+	cpx	#192						; 2
+	bcc	regular_scroll					; 2/3
+
+	lda	#$20
+	sta	vscroll_in_smc+2
+	sta	vscroll_out_smc+2
+	lda	#$00
+	sta	vscroll_in_smc+1
+	sta	vscroll_out_smc+1
+	beq	done_scroll_setup
+
+regular_scroll:
+	ldy	SCROLL_OFFSET					; 3
+	lda	hposn_high,Y					; 4
+	eor	#$60			; $20->$40		; 2
+	sta	vscroll_in_smc+2	; INH			; 4
+	lda	hposn_low,Y					; 4
+	sta	vscroll_in_smc+1	; INL			; 4
+								;====
+								; 21
+
+
+
+	lda	hposn_high,X					; 4
+	sta	vscroll_out_smc+2	; OUTH			; 4
+	lda	hposn_low,X					; 4
+	sta	vscroll_out_smc+1	; OUTL			; 4
+								;====
+								; 21
+done_scroll_setup:
+
+	inc	SCROLL_OFFSET					; 5
+
+
+	ldy	#39						; 2
+vscroll_bottom_line:
+
+vscroll_in_smc:
+	lda	$A000,Y						; 4
+vscroll_out_smc:
+	sta	$2000,Y						; 5
+	dey							; 2
+	bpl	vscroll_bottom_line				; 2/3
+								;=====
+								; 2+40*(14)-1
+								; 561
+
+	inx							; 2
+
+	txa
+	sec
+	sbc	SCROLL
+	cmp	#58
+	bcc	vscroll_bottom
+							;==========
+							;5+96*(42+561+7)-1
+							; 58564
+
+done_scroll:
+
+	;=====================
+	; scroll whole screen
+
+	dec	SCROLL
+	bne	vscroll_loop
+
+	rts
diff --git a/games/sb/purple.s b/games/sb/purple.s
index f84428d2..80476aa0 100644
--- a/games/sb/purple.s
+++ b/games/sb/purple.s
@@ -25,10 +25,9 @@ play_purple:
 	ldx	#PURPLE_LENGTH			; 28 pages long???
 	jsr	play_audio
 
-        ; read/write RAM, $d000 bank 2
+        ; read ROM/no-write
 
-	bit     $c08B
-	bit     $c08B
+	bit     $c082
 
 done_play_purple:
 	rts
diff --git a/games/sb/title.s b/games/sb/title.s
index 7ed4b06d..e4b52355 100644
--- a/games/sb/title.s
+++ b/games/sb/title.s
@@ -14,10 +14,11 @@ hires_start:
 	;===================
 	jsr	HOME
 
-	bit	HIRES
+	jsr	HGR
+;	bit	HIRES
 	bit	FULLGR
-	bit	SET_GR
-	bit	PAGE1
+;	bit	SET_GR
+;	bit	PAGE1
 
 	;====================
 	; set up tables
@@ -64,6 +65,9 @@ yes_language_card:
 
 	jsr	full_decomp
 
+	; read ROM/no-write
+	bit	$C082
+
 
 no_language_card:
 
@@ -86,7 +90,7 @@ scroll_logo:
 	sta	ZX0_src+1
 
 
-	lda	#$A0
+	lda	#$40
 
 	jsr	full_decomp
 
@@ -152,7 +156,7 @@ done:
 
 	.include	"zx02_optim.s"
 	.include	"hgr_tables.s"
-	.include	"hgr_vscroll.s"
+	.include	"hgr_logo_scroll.s"
 	.include	"audio.s"
 	.include	"purple.s"
 	.include	"lc_detect.s"