lorom
;Item finder by Black Falcon

;If there is any item in the room that hasn't been picked up yet, you'll get notified in the HUD

org $A0868F ;main hijack point

JSR $FFB0

org $A0FFB0 				; push stuff in case it's needed later
	PHA
	PHX
	JSL CHECKPLM
	PLX
	PLA
	LDA $1840 				;pull stuff after the routine is run and do what the hijack jump overwrote
	RTS
	
org $90F640

!item = #$1475								;tile to display if an item is present
!noitem = #$1477								;ditto if no item is present in the room

ITEMFINDER:
	SEP #$20 : LDA #$8F
	PHA : PLB : REP #$20
	LDA !noitem : STA $18						;assumes that there is no item in the room before the check
	LDX $07BB : LDA $8F0014, X : STA $12		;reads out current PLM pointer
LOOP:	
	LDA ($12) : BEQ NOMOREITEMS					;loads value stored at the pointer, ie detects header, if no header is found, no item is found
	CMP #$DF7D : BMI INCREASE					;checks items
	CMP #$F0A0 : BPL NOMOREITEMS				;checks custom PLMS
	LDA $12 : CLC : ADC #$0004					;we want to read out LO
	STA $14
	LDA ($14) : AND #$00FF
	JSL ITEMCHECKROUTINE : BCS INCREASE			;SEC if item has been picked up, CLC if not
	LDA !item : STA $18 : BRA NOMOREITEMS			;if even just one is found, you can jump out right here
INCREASE:
	LDA $12 : CLC : ADC #$0006
	STA $12 : BRA LOOP
NOMOREITEMS:
	LDA $18 : STA $7EC616 : RTL
	
ITEMCHECKROUTINE:
	PHX : PHY : PHP : REP #$30
	JSR $80818E
	LDA $7ED870,x : AND $05E7 : BNE SET	;checks item bit
	PLP : PLY : PLX : CLC : RTL
SET:
	PLP : PLY : PLX : SEC : RTL