;When you apply this patch, if you go above the screen till Mario becomes invisible, causes the
;game to display an 8x8 graphic showing the player's x position. Useful if your hack deals with
;being above the screen.

!TileSize = $00
;^#$00 = 8x8 tile
; #$02 = 16x16 tile

!TileNumber = $1D
;^The tile number seen on the 8x8 tile editor. See bottom status bar (not SMW's!) and use the
;last two hex digits. If 16x16 tile, would be the top left of it.

!TileProp = %00110000
;^Tile properties, in binary (%). YXPPCCCT format:
;-X and Y are flips.
;-PP are priority:
;--00 = behind all except Layer 3 tiles with priority setting 0.
;--01 = behind all except Layer 3 tiles (unless they have priority setting 1 and the "force
;  above everything" bit is set)
;--10 = In front of layer 3 (unless they have priority setting 1 and the "force above everything"
;  bit is set) and Layer 1 and 2 tiles with priority setting 0; appear behind Layer 1 and 2 tiles
;  with priority setting 0 (this is SMW's normal setting for most sprites)
;--11 = Appear in front of everything, except Layer 3 tiles with priority setting 1 if the "force
;  above everything" bit is set.
;-CCC = palette to use:
;--000 = 8
;--001 = 9
;--010 = A
;--011 = B
;--100 = C
;--101 = D
;--110 = E
;--111 = F
;-T = Use 2nd page if set.

!PositionMarker_Y_Position = $08
;^The Y position the marker is being displayed. $00 Indicates the top of the screen, while $E0
;is the bottom.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;SA1 detector:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
if read1($00FFD5) == $23
	!SA1 = 1
	sa1rom
else
	!SA1 = 0
endif

; Example usage
if !SA1
	; SA-1 base addresses	;Give thanks to absentCrowned for this:
				;http://www.smwcentral.net/?p=viewthread&t=71953
	!Base1 = $3000		;>$0000-$00FF -> $3000-$30FF
	!Base2 = $6000		;>$0100-$0FFF -> $6100-$6FFF and $1000-$1FFF -> $7000-$7FFF
else
	; Non SA-1 base addresses
	!Base1 = $0000
	!Base2 = $0000
endif

assert !TileSize == $00 || !TileSize == $02, "Invalid number."
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;Hijack
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
org $00F71A                  ;>The address that is part of the scrolling routine (compatable with center scroll)
	autoclean JSL DisplayMarioXPos
	nop

freecode
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;Main code
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DisplayMarioXPos:          ;>16-bit mode A
	PHP                ;>Save processor mode into stack (no effect on it though)
	PHY                ;>Save Y into stack
	LDA $71            ;\Don't display if player is dying.
	BNE .Done          ;/
	LDA $96            ;\Y position on-screen (MarioYPos - ScreenYPos)
	SEC                ;|Not use $80 since that does not get updated until next frame
	SBC $1C            ;/
	CMP #$FFE0         ;\If player was below that point, return. (His coordinate point is 1 block above mario
	BEQ +              ;|when small or ducking). The BEQ makes it so that you don't have to jump just to reveal
	BPL .Done          ;/a marker.
+	JSR DisplayXPos
.Done
	PLY                ;>Load Y
	PLP                ;>load processor back into 16-bit A
.RestoreCode
	LDA $94            ;\X position on-screen (MarioXPos - ScreenXPos) (restore code)
	SEC                ;|
	SBC $1A            ;/
	RTL

DisplayXPos:
	JSR FindOam
	BCS .Done            ;>If no open slots, return.
.WriteTile
	if !TileSize == $00
		REP #$20
		LDA $7E                          ;\Tile X position on-screen ($7E is Mario's x pos on-screen, 16-bit)
		CLC
		ADC #$0004                       ;>Adjust from Mario's position (so it's centered with Mario)
		SEP #$20                         ;>Go back into 8-bit A
		XBA                              ;>Read only the high byte X position
		BNE .Done                        ;>If High byte is not zero (x pos that is not on screen), don't draw (gfx will wrap).
		XBA                              ;>Revert the value back to use low byte
	else
		LDA $7F                          ;\If Mario offscreen, return.
		BNE .Done                        ;/
		LDA $7E                          ;>Use low byte of player's x pos on-screen
	endif

	STA $0200+!Base2,y               ;>And set tile X position on-screen.

	LDA #!PositionMarker_Y_Position  ;\Tile Y position on-screen
	STA $0201+!Base2,y               ;/

	LDA #!TileNumber                 ;\Tile to use
	STA $0202+!Base2,y               ;/

	LDA.b #!TileProp                 ;\Tile properties
	STA $0203+!Base2,y               ;/

	LDY.b #!TileSize                 ;>Y = Tile size
	LDA.b #$00                       ;>Minus 1 (if you wanted 1 tile, put zero)
	JSL $01B7B3                      ;>Write OAM
.Done
	RTS

FindOam:
	LDY #$00           ;>Start at highest priority (appearing in front of most sprites)
.Loop
	LDA $0201,y        ;>The Y tile position on-screen, #$F0 = free slot.
	CMP #$F0           ;\If slot used, go to next one
	BEQ .NextSlot      ;/
.FreeSlot
	CLC
	RTS

.NextSlot
	INY
	INY
	INY
	INY
	CPY #$6C
	BCC .Loop          ;>If useable slot, check it.
	SEC                ;>If Y is on an invalid index, break loop and set carry to indicate "no slots left"
	RTS