Ground Attack: Routine at 6D1F

6D1F: Erase all sprites from screen.

Used by the routine at Game_Update.
Sprite_EraseAll	6D1F	LD HL,Sprite_LastSlot	Start with the last sprite and work back.
	6D22	LD B,$0F	Start with the last sprite and work back.
Sprite_EraseAll_0	6D24	PUSH BC	Get offset position for next sprite
	6D25	LD D,(HL)
	6D26	DEC HL
	6D27	LD E,(HL)
	6D28	LD A,D
	6D29	OR E
	6D2A	JR Z,Sprite_EraseAll_1
	6D2C	PUSH HL
	6D2D	LD HL,$57FF	Erase position on ATTR screen
	6D30	ADD HL,DE
	6D31	LD (HL),$00
	6D33	POP HL
	6D34	EX DE,HL
	6D35	LD A,$20	Erase char on DF
	6D37	PUSH DE
	6D38	CALL CharBlit
	6D3B	POP HL
Sprite_EraseAll_1	6D3C	DEC HL	Next slot
	6D3D	DEC HL
	6D3E	DEC HL
	6D3F	POP BC
	6D40	DJNZ Sprite_EraseAll_0
	6D42	RET
	6D43	NOP
	6D44	NOP
	6D45	NOP
	6D46	NOP
	6D47	NOP
	6D48	NOP
	6D49	NOP
	6D4A	NOP
	6D4B	NOP
	6D4C	LD A,$0A
	6D4E	LD (_7904),A
	6D51	LD (Item_ShipX),A
	6D54	LD C,$16
	6D56	LD HL,_7f15
	6D59	LD DE,$FFE0
Sprite_EraseAll_2	6D5C	ADD HL,DE
	6D5D	DEC C
	6D5E	LD A,(HL)
	6D5F	CP $20
	6D61	JR NZ,Sprite_EraseAll_2
	6D63	LD A,(Land_Gap)
	6D66	SRA A
	6D68	LD B,A
	6D69	LD A,C	Get row and key currently being pressed.
	6D6A	SUB B
	6D6B	LD ($7903),A
	6D6E	LD (Item_ShipY),A
	6D71	LD H,$00
	6D73	LD L,A
	6D74	DEC HL
	6D75	ADD HL,HL
	6D76	ADD HL,HL
	6D77	ADD HL,HL
	6D78	ADD HL,HL
	6D79	ADD HL,HL
	6D7A	LD BC,$000A
	6D7D	ADD HL,BC
	6D7E	LD (Item_Copies_ShipOffset),HL
	6D81	LD (Item_ShipPosOffset),HL
	6D84	RET
	6D85	NOP
	6D86	NOP
	6D87	NOP