From 7ea451361a4d6ebcd701262c289345404d81395a Mon Sep 17 00:00:00 2001
From: Andrew Kesterson <andrew@aklabs.net>
Date: Sun, 4 Nov 2012 12:25:10 -0500
Subject: [PATCH] Pointers working for the NMI OAM copy, thanks Ophis

---
 defines.S |  3 ++-
 nesgame.S | 37 ++++++++++++++++++++++---------------
 2 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/defines.S b/defines.S
index b29a7d2..bdf46f7 100644
--- a/defines.S
+++ b/defines.S
@@ -1 +1,2 @@
-  .alias curSpriteData curSpriteDataHi
\ No newline at end of file
+  .alias curSpriteDataRead curSpriteDataLo
+  .alias curSpriteDataWrite curSpriteDataHi
\ No newline at end of file
diff --git a/nesgame.S b/nesgame.S
index d2c8432..36a7d44 100644
--- a/nesgame.S
+++ b/nesgame.S
@@ -199,34 +199,41 @@ _MAIN_loop:
 NMI:
 	LDX #$0
 	LDY #$0
+	;; This is almost a reusable function ... store 'sprMario' as our
+	;; current sprite that we're about to draw
 	LDA sprMario
 	STA curSpriteLen
+	LDA #>sprMarioData
+	STA curSpriteDataHi
+	LDA #<sprMarioData
+	STA curSpriteDataLo
+	;; ----
 _NMI_CopyMarioToOAM:
 	LDA playery		; set Y position
 	CLC
-	ADC sprMarioData, x
-	STA $0200, x
-	INX
-	LDA sprMarioData, x	; set tile number
-	STA $0200, x
-	INX
+	ADC (curSpriteDataLo), y
+	STA $0200, y
+	INY
+	LDA (curSpriteDataLo), y	; set tile number
+	STA $0200, y
+	INY
 	LDA pad1a
 	AND #%00000001
 	BNE _NMI_CopyMarioToOAM_padup
-	LDA sprMarioData, x
+	LDA (curSpriteDataLo), y
 	JMP _NMI_CopyMarioToOAM_paddone
 _NMI_CopyMarioToOAM_padup:	
-	LDA sprMarioData, x	; set attributes
+	LDA sprMarioData, y	; set attributes
 _NMI_CopyMarioToOAM_paddone:	
-	STA $0200, x
-	INX
+	STA $0200, y
+	INY
 	LDA playerx		; set X position
 	CLC
-	ADC sprMarioData, x
-	STA $0200, x
-	INX
-	INY			; increment the sprite counter
-	CPY curSpriteLen	; any more sprites in the current multisprite?
+	ADC (curSpriteDataLo), y
+	STA $0200, y
+	INY
+	INX			; increment the sprite counter
+	CPX curSpriteLen	; any more sprites in the current multisprite?
 	BNE _NMI_CopyMarioToOAM
 	
 	;; We need to copy all our OAM data to put sprites on screen during