Avalon: Routine at D5FE

D5FE: Prepare data for any creatures that are entering Maroc's room


For a creature entering the room - sets up graphics and determines its speed/direction of movement.
D5FE	LD A,($EBB7)	Creature type (see EB46)
D601	CP $00	Creature type (see EB46)
D603	JR Z,$D63A	If no creature, skip to the next routine
D605	CALL $E16A	This routine sets up data for creatures/warlocks appearing in Maroc's room (the A register normally contains creature type/number from EB46)
D608	LD A,($EBB8)	Creature's horizontal position (in 4 pixel steps) in room, after entering through a door
D60B	LD ($EB48),A	Copy to graphic data buffer
D60E	LD C,A	Copy to graphic data buffer
D60F	LD A,($EBB9)	Creature's vertical pixel position in room, after entering through a door
D612	SUB $0E	Adjust slightly by moving vertical position up 14 pixels. This puts the creatures in the doorway itself when they appear, rather than looking as if they've appeared a couple of feet into the room
D614	LD ($EB4A),A	Copy to graphic data buffer
Calculate which area of the room (left, right or back wall door) the creature is entering from, and set their speed/direction accordingly:
D617	LD DE,$0004	If the forthcoming checks don't hit a match, the creature is between the room floor/wall connectors, so entering through a BACK WALL DOOR
D61A	LD A,C	(Superfluous instruction, as this value is immediately overwritten in next one)
D61B	LD A,($EAFB)	Left room corner section - floor/wall connector - graphic's horizontal position, in half character squares (4 pixel steps)
D61E	CP C	Compare with creature's horizontal position (also in 4 pixel steps)
D61F	JR C,$D626
D621	LD DE,$0400	Creature is to the left of the room's left connector, so entering through a LEFT WALL DOOR
D624	JR $D62F
D626	LD A,($EAFC)	Right wall corner section - floor/wall connector - graphic's horizontal position, in half character squares (4 pixel steps)
D629	CP C	Compare with creature's horizontal position (also in 4 pixel steps) in room
D62A	JR NC,$D62F
D62C	LD DE,$FC00	Creature is to the right or the room's right (wall/floor) connector graphics - so entering through a RIGHT WALL DOOR
The result in the DE registers is used to set the creature's horizontal (EB4C) and vertical (EB4D) speed/direction Back wall door: E (vertical) = +4, D (horizontal) = 0 Left wall door: E (vertical) = 0, D (horizontal) = +4 Right wall door: E (vertical) = 0, D (horizontal) = -4 (252)
D62F	LD A,D
D630	LD ($EB4C),A	Horizontal speed/direction
D633	LD A,E	Horizontal speed/direction
D634	LD ($EB4D),A	Vertical speed/direction
D637	JP $D6C7	Vertical speed/direction