Lunar Jetman: Routine at 9466

9466: Routine at 9466

Used by the routine at 8258.
9466	LD A,R	A=random number.
9468	AND %00000011	Keep only bits 0-1.
946A	RET NZ	Return if the value is not zero.
946B	LD A,($5E67)	A=GameDelayTimer.
946E	AND A	Return if the value is not zero.
946F	RET NZ	Return if the value is not zero.
9470	CALL FindSlotAlien	Call FindSlotAlien.
9473	RET NZ	Return if there were no available alien slots.
9474	PUSH HL	Stash HL (the free alien slot) on the stack.
9475	EX DE,HL	Switch the DE and HL registers.
9476	LD A,($5E40)	A=5E40.
9479	RLA	Rotate A left once.
947A	AND %00001110	Keep only bits 1-3.
947C	LD C,A	Create an offset in BC - max 0E (only even numbers).
947D	LD B,$00	Create an offset in BC - max 0E (only even numbers).
947F	LD A,($5EA0)	A=ActivePlayer_Level.
9482	CP $0C	Compare the current level against 0C if there's any carry over then jump to 9488.
9484	JR C,$9488
9486	LD A,$0C	A=0C.
9488	AND %00001110	Keep only bits 1-3.
948A	LD L,A	Create an offset in HL - number can be: 0002 0004 0006 0008 000A 000C
948B	LD H,$00
948D	LD DE,$9D72	HL+=LevelsAlienLookupTable.
9490	ADD HL,DE	HL+=LevelsAlienLookupTable.
9491	LD A,(HL)	HL=alien lookup table appropriate for the current level.
9492	INC HL
9493	LD H,(HL)
9494	LD L,A
9495	ADD HL,BC	HL+=BC.
9496	LD A,(HL)	HL=an alien from the level lookup table.
9497	INC HL
9498	LD H,(HL)
9499	LD L,A
949A	LD BC,$0018	BC=0018.
949D	POP DE	DE=the free alien slot (from earlier).
949E	PUSH DE	Stash DE (the free alien slot) on the stack again.
949F	LDIR	Copy the alien data to the free alien slot.
94A1	POP HL	HL=the free alien slot.
94A2	LD A,(HL)
94A3	INC HL
94A4	INC HL
94A5	PUSH HL
94A6	LD HL,($607A)
94A9	CP $88
94AB	JR Z,$94DB
94AD	CP $B8
94AF	JP Z,$9506
94B2	LD A,($5E40)
94B5	LD C,A
94B6	LD B,$00
94B8	LD DE,$0080
94BB	AND $02
94BD	JR Z,$94C5
94BF	SBC HL,BC
94C1	SBC HL,DE
94C3	JR $94C7
94C5	ADD HL,BC
94C6	ADD HL,DE
94C7	LD A,H
94C8	AND %00011111	Keep only bits 0-4.
94CA	LD H,A
94CB	EX DE,HL
94CC	POP HL
94CD	LD (HL),E
94CE	INC HL
94CF	LD (HL),D
94D0	INC HL
94D1	INC HL
94D2	LD A,C
94D3	AND %10000000	Keep only bit 7.
94D5	RET Z
94D6	LD A,(HL)
94D7	NEG
94D9	LD (HL),A
94DA	RET	Return.
94DB	LD A,($5E40)	A=5E40.
94DE	LD B,A	B=A.
94DF	AND %10000000	Keep only bit 7.
94E1	SUB $40
94E3	LD C,A
94E4	JP P,$94EC
94E7	LD DE,$0090	DE=0090.
94EA	JR $94EF	Jump to 94EF.
94EC	LD DE,$FF70
94EF	ADD HL,DE
94F0	LD A,H
94F1	AND %00011111	Keep only bits 0-4.
94F3	LD H,A
94F4	EX DE,HL
94F5	POP HL
94F6	LD (HL),E
94F7	INC HL
94F8	LD (HL),D
94F9	INC HL
94FA	LD A,B
94FB	AND %01111000	Keep only bits 3-6.
94FD	JR NZ,$9500
94FF	INC A
9500	ADD A,$37
9502	LD (HL),A
9503	INC HL
9504	LD (HL),C
9505	RET
9506	LD A,($5E40)
9509	LD B,A
950A	AND %10000000	Keep only bit 7.
950C	SUB $40
950E	LD C,A
950F	JP P,$9517
9512	LD DE,$0090	DE=0090.
9515	JR $951A	Jump to 951A.
9517	LD DE,$FF70	DE=FF70.
951A	ADD HL,DE
951B	LD A,H
951C	AND $1F
951E	LD H,A
951F	EX DE,HL
9520	POP HL
9521	LD (HL),E
9522	INC HL
9523	LD (HL),D
9524	INC HL
9525	LD A,B
9526	AND %01111000	Keep only bits 3-6.
9528	JR NZ,$952B
952A	INC A
952B	ADD A,$37
952D	LD (HL),A
952E	INC HL
952F	LD (HL),C
9530	RET	Return.