PAGE
	SBTTL "--- OBJECT & PROPERTY HANDLERS ---"

	; ----------------------------------
	; GET ABSOLUTE ADDRESS OF OBJECT [A]
	; ----------------------------------

	; EXIT: ADDRESS IN [I]

OBJLOC:	STA	I+LO		; SAVE LSB FOR ADDING

	LDX	#0		; CLEAR MSB
	STX	I+HI		; FOR SHIFTING

	ASL	A		; MULTIPLY BY 8
	ROL	I+HI
	ASL	A
	ROL	I+HI
	ASL	A
	ROL	I+HI

	CLC			; ADD TO ITSELF
	ADC	I+LO		; TO GET TIMES 9
	BCC	OBJ1
	INC	I+HI

OBJ1:	CLC
	ADC	#53		; NOW ADD 53
	BCC	OBJ2		; (THE OBJECT TABLE OFFSET)
	INC	I+HI

OBJ2:	CLC			; NEXT ADD THE ABS ADDR
	ADC	OBJTAB+LO	; OF THE OBJECT TABLE
	STA	I+LO

	LDA	I+HI
	ADC	OBJTAB+HI
	STA	I+HI
	RTS

	; -----------------------------
	; GET ADDRESS OF PROPERTY TABLE
	; -----------------------------

	; EXIT: [I] HAS ABSOLUTE ADDR OF PROPERTY TABLE
	;       [Y] HAS OFFSET TO START OF PROP IDS

PROPB:	LDA	ARG1+LO
	JSR	OBJLOC
	LDY 	#7
	LDA	(I),Y		; GET MSB OF P-TABLE ADDRESS
	CLC
	ADC	ZCODE		; MAKE IT ABSOLUTE
	TAX			; AND SAVE HERE
	INY
	LDA	(I),Y		; NOW GET LSB
	STA	I+LO
	STX	I+HI		; [I] NOW POINTS TO PROP TABLE

	LDY	#0
	LDA	(I),Y		; GET LENGTH OF SHORT DESC
	ASL	A		; WORD-ALIGN IT
	TAY			; EXPECTED HERE
	INY			; POINT JUST PAST THE DESCRIPTION
	RTS

	; -------------------
	; FETCH A PROPERTY ID
	; -------------------

	; ENTRY: LIKE "PROPB" EXIT

PROPN:	LDA	(I),Y
	AND	#%00011111	; MASK OUT LENGTH BITS
	RTS

	; -------------------------------
	; FETCH # BYTES IN PROPERTY VALUE
	; -------------------------------

	; ENTRY: LIKE "PROPB" EXIT

PROPL:	LDA	(I),Y
	LSR	A		; LENGTH IS IN
	LSR	A		; BITS 7-5
	LSR	A		; SO SHIFT INTO PLACE
	LSR	A
	LSR	A
	RTS

	; ----------------------
	; POINT TO NEXT PROPERTY
	; ----------------------

	; ENTRY: LIKE "PROPB" EXIT

PROPNX:	JSR	PROPL		; GET LENGTH OF CURRENT PROP
	TAX			; SAVE HERE

PPX:	INY			; LOOP UNTIL
	DEX			; [Y] POINTS TO
	BPL	PPX		; START OF NEXT PROP
	INY			; CORRECT ALIGNMENT
	RTS

	; ----------------
	; GET OBJECT FLAGS
	; ----------------

	; ENTRY: OBJECT # IN [ARG1], FLAG # IN [ARG2]
	; EXIT: FLAG WORD IN [K], BIT ID IN [J],
	;       FLAG WORD ADDRESS IN [I]

FLAGSU:	LDA	ARG1+LO
	JSR	OBJLOC		; GET OBJECT ADDR IN [I]

	LDA	ARG2+LO		; LOOK AT FLAG ID
	CMP	#$10		; FIRST SET OF FLAGS?
	BCC	FLS1		; YES, ADDR IN [I] IS CORRECT

	SBC	#16		; ELSE ZERO-ALIGN FLAG INDEX
	TAX			; SAVE IT HERE

	LDA	I+LO		; ADD 2 TO ADDRESS IN [I]
	CLC			; TO POINT TO ADDRESS OF
	ADC	#2		; 2ND FLAG WORD
	STA	I+LO
	BCC	FLS0
	INC	I+HI

FLS0:	TXA			; RESTORE INDEX

FLS1:	STA	K+LO		; SAVE FLAG ID HERE

	LDX	#1		; INIT THE
	STX	J+LO		; FLAG WORD TO
	DEX			; $0001
	STX	J+HI

	LDA	#15		; SUBTRACT THE BIT POSITION
	SEC			; FROM 15
	SBC	K+LO		; TO GET THE SHIFT LOOP
	TAX			; INDEX
	BEQ	FLS2		; EXIT NOW IF NO SHIFT NEEDED

FLSL:	ASL	J+LO		; SHIFT THE BIT
	ROL	J+HI		; INTO POSITION
	DEX
	BNE	FLSL

FLS2:	LDY	#0		; MOVE THE FLAG WORD
	LDA	(I),Y		; INTO [J]
	STA	K+HI		; FIRST THE MSB
	INY
	LDA	(I),Y
	STA	K+LO		; THEN THE LSB
	RTS

	END