Wheelie: Routine at 6650

6650: Routine at 6650

Used by the routines at 6AAC, 6C00 and 6E18.
6650	LD HL,($7817)	HL=*7817.
6653	LD A,($7819)	Jump to 6667 if *7819 is not zero.
6656	AND A
6657	JR NZ,$6667
6659	LD A,L	Jump to 6661 if L is not zero.
665A	AND A
665B	JR NZ,$6661
665D	LD A,H	H-=05.
665E	SUB $05
6660	LD H,A
6661	DEC L	Decrease L by one.
6662	LD ($7817),HL	Write HL to *7817.
6665	LD A,$08	A=08.
6667	DEC A	Decrease A by one.
6668	LD ($7819),A	Write A to *7819.
666B	LD D,H	D=H.
666C	LD E,L	E=L.
666D	LD B,$FF	B=FF.
666F	CALL $6564	Call 6564.
6672	LD HL,$4000	HL=4000 (screen buffer).
6675	LD D,H	D=H.
6676	LD E,L	E=L.
6677	EXX	Switch to the shadow registers.
6678	LD A,(DE)	A=*DE.
6679	INC E	Increment E by one.
667A	LD L,A	L=A.
667B	LD H,$1F	H=1F.
667D	ADD HL,HL	HL+=HL.
667E	ADD HL,HL	HL+=HL.
667F	EXX	Switch to the shadow registers.
6680	LD B,$04	B=04.
6682	EXX	Switch to the shadow registers.
6683	LD A,(HL)	A=*HL.
6684	INC L	Increment L by one.
6685	EXX	Switch to the shadow registers.
6686	RRD	RRD.
6688	INC L	Increment L by one.
6689	RRD	RRD.
668B	INC L	Increment L by one.
668C	RRD	RRD.
668E	INC L	Increment L by one.
668F	RRD	RRD.
6691	INC L	Increment L by one.
6692	RRD	RRD.
6694	INC L	Increment L by one.
6695	RRD	RRD.
6697	INC L	Increment L by one.
6698	RRD	RRD.
669A	INC L	Increment L by one.
669B	RRD	RRD.
669D	INC L	Increment L by one.
669E	RRD	RRD.
66A0	INC L	Increment L by one.
66A1	RRD	RRD.
66A3	INC L	Increment L by one.
66A4	RRD	RRD.
66A6	INC L	Increment L by one.
66A7	RRD	RRD.
66A9	INC L	Increment L by one.
66AA	RRD	RRD.
66AC	INC L	Increment L by one.
66AD	RRD	RRD.
66AF	INC L	Increment L by one.
66B0	RRD	RRD.
66B2	INC L	Increment L by one.
66B3	RRD	RRD.
66B5	INC L	Increment L by one.
66B6	RRD	RRD.
66B8	INC L	Increment L by one.
66B9	RRD	RRD.
66BB	INC L	Increment L by one.
66BC	RRD	RRD.
66BE	INC L	Increment L by one.
66BF	RRD	RRD.
66C1	INC L	Increment L by one.
66C2	RRD	RRD.
66C4	INC L	Increment L by one.
66C5	RRD	RRD.
66C7	INC L	Increment L by one.
66C8	RRD	RRD.
66CA	INC L	Increment L by one.
66CB	RRD	RRD.
66CD	INC L	Increment L by one.
66CE	RRD	RRD.
66D0	INC L	Increment L by one.
66D1	RRD	RRD.
66D3	INC L	Increment L by one.
66D4	RRD	RRD.
66D6	INC L	Increment L by one.
66D7	RRD	RRD.
66D9	INC L	Increment L by one.
66DA	RRD	RRD.
66DC	INC L	Increment L by one.
66DD	RRD	RRD.
66DF	INC L	Increment L by one.
66E0	RRD	RRD.
66E2	INC L	Increment L by one.
66E3	RRD	RRD.
66E5	LD L,E	L=E.
66E6	INC H	Increment H by two.
66E7	INC H	Increment H by two.
66E8	DJNZ $6682	Decrease counter by one and loop back to 6682 until counter is zero.
66EA	LD A,$20	E+=20.
66EC	ADD A,E
66ED	LD E,A
66EE	LD L,A	L=A.
66EF	JR NC,$66F3	Jump to 66F3 if {} is higher.
66F1	LD D,$48	D=48.
66F3	LD H,D	H=D.
66F4	EXX	Switch to the shadow registers.
66F5	DJNZ $6678	Decrease counter by one and loop back to 6678 until counter is zero.
66F7	EXX	Switch to the shadow registers.
66F8	RET	Return.