Offscreen Indicator

; Offscreen indicator. Displays a small sprite at the top/bottom of the screen to show where Mario is when he's offscreen.
;  Change the settings below as you need to, then insert with UberASM as either level asm or gamemode asm (for mode 14).

!tileAbove	=	$1D		; 8x8 tile to use for the marker when above the screen.
!propsAbove	=	$28		; YXPPCCCT properties for the tile when above the screen.
!yOffAbove	=	$02		; How many pixels below the very top of the screen that the tile should appear.

!tileBelow	=	$1D		; 8x8 tile to use for the marker when below the screen.
!propsBelow	=	$28		; YXPPCCCT properties for the tile when below the screen.
!yOffBelow	=	$02		; How many pixels below the very bottom of the screen that the tile should appear.

;;;

!oamIndex	=	$0000	; OAM index from $0200 to use.
	; ^ don't touch this one unless you know how it works
	;   the default value isn't really used by much so it should be fine


;;;;;
; Code begins
main:
	LDY #$00
	REP #$20
	LDA $80
	CMP #$FFE1
	BMI .offscreen
	LDX $19
	BNE +
	CLC : ADC #$0008
  +	CMP #$00DA
	BMI .ret
	LDY #$01

  .offscreen
	SEP #$20
	LDA $7E
	CLC : ADC #$04
	STA $0200+!oamIndex
	LDA yOffs,y
	STA $0201+!oamIndex
	LDA Tiles,y
	STA $0202+!oamIndex
	LDA Props,y
	STA $0203+!oamIndex
	STZ $0420+(!oamIndex/4)

  .ret
	SEP #$20
	RTL

Tiles:
	db !tileAbove,!tileBelow
Props:
	db !propsAbove,!propsBelow
yOffs:
	db !yOffAbove,$D8-!yOffBelow