Refactored slideshow example

023.slideshow/disk.s

@@ -0,0 +1,27 @@
+	xdef	LoadDiskData
+	
+LoadDiskData:
+	;; a0 - destination address
+	;; a1 - start address
+	;; d0 - size
+	movem.l	d0-a6,-(sp)
+	lea 	$dff002,a6	; LoadMFMB uses this custom base addr
+
+	move.l	d0,d1
+	
+	move.l	a1,d0
+	move.l	#startCode,d2
+	sub.l	d2,d0		; offset from start of this module
+	lsr.l	#6,d0		; bytes -> sectors
+	lsr.l	#3,d0		
+	add.l	#2,d0		; offset for bootblock
+
+	
+	add.l	#512,d1
+	lsr.l	#6,d1		; bytes -> sectors
+	lsr.l	#3,d1
+	neg.w	d1
+	jsr 	LoadMFMB	; load the data!
+	
+	movem.l (sp)+,d0-a6
+	rts