Atic Atac: Routine at 32195

Used by the routines at DrawRoom and EnterRoom.

Runs the game one entity at a time. Whenever FRAMES has changed since the last time, UpdateFixedEntities runs the handlers of the three fixed entities starting at Player. Each entity from ItemEntities onwards that is in the same room as the player is then given to ProcessAction, and every 16-byte record from CreatureRecords onwards after that. Finally the room items are processed by DrawRoom. If the room has not been drawn yet (bit 0 of GameFlags is clear) the entities are skipped and DrawRoom is run immediately.

Used by the routines at DrawRoom and EnterRoom. Runs the game one entity at a time. Whenever FRAMES has changed since the last time, UpdateFixedEntities runs the handlers of the three fixed entities starting at Player. Each entity from ItemEntities onwards that is in the same room as the player is then given to ProcessAction, and every 16-byte record from CreatureRecords onwards after that. Finally the room items are processed by DrawRoom. If the room has not been drawn yet (bit 0 of GameFlags is clear) the entities are skipped and DrawRoom is run immediately.
MainLoop	32195	LD SP,24064	Set stack pointer to 24064.
	32198	EI	Enable interrupts.
	32199	XOR A	Reset the number of creatures in NumCreatures to zero.
	32200	LD (24101),A	Reset the number of creatures in NumCreatures to zero.
	32203	LD IX,60072	Point IX at the first entity after the three fixed entities at ItemEntities.
	32207	LD A,(24084)	Jump to MainLoop_Entities if the entities in the room have already been drawn (bit 0 of GameFlags is set).
	32210	BIT 0,A
	32212	JR NZ,MainLoop_Entities
	32214	LD IX,61152	Point IX at the end of the entity table, so that no entities are processed at RoomItemEntities.
	32218	JR DrawRoom	Jump to DrawRoom to draw the room.
Each pass of this loop considers one of the 8-byte entities.
MainLoop_Entities	32220	LD A,(23672)	Fetch the low byte of FRAMES into C (using A).
	32223	LD C,A	Fetch the low byte of FRAMES into C (using A).
	32224	LD A,(24067)	Fetch the FRAMES value from the previous pass.
	32227	CP C	Call UpdateFixedEntities if FRAMES has changed since it was last stored in LastFrame.
	32228	CALL NZ,UpdateFixedEntities
	32231	LD A,(60049)	Fetch the room of the player.
	32234	CP (IX+1)	Compare it with the room of this entity.
	32237	LD HL,32243	Point HL at the address for the handler to return to at MainLoop_NextEntity.
	32240	JP Z,ProcessAction	Process the entity with ProcessAction if it is in the same room as the player.
Move on to the next 8-byte entity.
MainLoop_NextEntity	32243	LD DE,8	DE=0008 (the size of an entity).
	32246	ADD IX,DE	Move IX on to the next entity.
	32248	PUSH IX	Copy IX to HL (using the stack).
	32250	POP HL	Copy IX to HL (using the stack).
	32251	LD DE,61024	Point DE at the end of the 8-byte entities at CreatureRecords.
	32254	AND A	Jump back to MainLoop_Entities until IX reaches CreatureRecords.
	32255	SBC HL,DE
	32257	JR C,MainLoop_Entities
Now work through the 16-byte records. These are processed no matter which room the player is in.
MainLoop_Records	32259	LD A,(23672)	Fetch the low byte of FRAMES into C (using A).
	32262	LD C,A	Fetch the low byte of FRAMES into C (using A).
	32263	LD A,(24067)	Fetch the FRAMES value from the previous pass.
	32266	CP C	Call UpdateFixedEntities if FRAMES has changed since it was last stored in LastFrame.
	32267	CALL NZ,UpdateFixedEntities
	32270	LD HL,32275	Point HL at the address for the handler to return to at MainLoop_NextRecord.
	32273	JR ProcessAction	Jump to ProcessAction to process the record.
MainLoop_NextRecord	32275	LD DE,16	DE=0016 (the size of a record).
	32278	ADD IX,DE	Move IX on to the next record.
	32280	PUSH IX	Copy IX to HL (using the stack).
	32282	POP HL	Copy IX to HL (using the stack).
	32283	LD DE,61152	Point DE at the end of the entity table at RoomItemEntities.
	32286	AND A	Jump back to MainLoop_Records until IX reaches RoomItemEntities.
	32287	SBC HL,DE
	32289	JR C,MainLoop_Records