Sabre Wulf: Routine at B939

B939: Prepare Draw 2/ 3 Byte Sprite

Used by the routines at RemoveEntity and DisplayEntity.
PrepDraw23	B939	CALL GetSpriteA	Call GetSpriteA.
	B93C	LD HL,($96A0)	HL=Saved_X (saved X position).
	B93F	LD A,L
	B940	DEC A
	B941	RLCA
	B942	AND %00001110	Keep only bits 1-3.
	B944	OR %11110000	Set bits 4-7.
	B946	LD B,A	Store the result in B.
	B947	LD A,(DE)
	B948	INC DE
	B949	NEG
	B94B	AND %00000111	Keep only bits 0-2.
	B94D	ADD A,A
	B94E	ADD A,A
	B94F	LD C,A
	B950	ADD A,A
	B951	ADD A,C
	B952	LD C,A
	B953	LD A,L
	B954	AND %00000111	Keep only bits 0-2.
	B956	LD A,C
	B957	JR NZ,PrepDraw23_0
	B959	ADD A,$06
PrepDraw23_0	B95B	LD ($BA13),A
	B95E	LD A,(DE)
	B95F	INC DE
	B960	LD ($96A3),A	Write A to SomeHeight.
	B963	CALL ScreenAddress	Call ScreenAddress.
	B966	LD C,$00	C=00.
	B968	RET	Return.