The Hobbit (v1.0): Routine at 9D92

Returns with Z reset if the object at IY is visible (bit 7 of its flags) and is in the same place as the object at IX.

Each object's outermost holder is found with 9DC8, which returns $FF for an object lying loose in a room and 0 for one that is shut inside something (or held by a living character). If the results differ, the objects are not together. If both are loose, IX's room must be one of IY's locations. If both are 0, the room comparison is skipped and they count as together - see the bug note.

Returns with Z reset if the object at IY is visible (bit 7 of its flags) and is in the same place as the object at IX. Each object's outermost holder is found with 9DC8, which returns $FF for an object lying loose in a room and 0 for one that is shut inside something (or held by a living character). If the results differ, the objects are not together. If both are loose, IX's room must be one of IY's locations. If both are 0, the room comparison is skipped and they count as together - see the bug note.
9D92	BIT 7,(IY+$07)	Is the IY object visible at all?
9D96	RET Z	No: return with Z set
9D97	PUSH IY
9D99	PUSH IX
9D9B	PUSH BC
9D9C	LD C,(IX+$10)	C = the IX object's room
9D9F	PUSH IY	C = the IX object's room
9DA1	CALL $9DC8	Where is the IY object ultimately?
9DA4	LD B,A
9DA5	POP IX
9DA7	CALL $9DC8	Where is the IX object ultimately?
9DAA	CP B	The same answer?
9DAB	JR NZ,$9DBD	No: not together
9DAD	INC A	Both shut inside something ($00)?
9DAE	JR NZ,$9DC0	Then count them as together
9DB0	LD B,(IY+$00)	Both loose: is the IX object's room one of the IY object's locations?
9DB3	LD A,C
9DB4	CP (IY+$10)
9DB7	JR Z,$9DC0	Yes: together
9DB9	INC IY
9DBB	DJNZ $9DB4
9DBD	XOR A	Not together: Z set
9DBE	JR $9DC2	Not together: Z set
9DC0	OR $01	Together: Z reset
9DC2	POP BC
9DC3	POP IX
9DC5	POP IY
9DC7	RET