Zaxxan

Zaxxan
Developer: Nial Mardon Publisher: Starzone Software Platform: ZX Spectrum Released in EU: 1983 This game has uncompiled source code.

Most. Obvious. Zaxxon clone. Ever.

Source Code Fragment

Beginning at 68B2 in the .tap dump, there's a piece of code lying in it.

                ,E 
        INC	HL
        LD	(HL),D
        DEC	H
        POP	BC
        LD	DE,(#DA06)
        LD	A,141
        LD	(DE),A
        JP	STOR
REVERS	LD	A,B
        CP      L
        LD	B,A
        LD	A,C
        CP      L
        INC	A
        LD	C,A
        EX	DE,HL
        ADD	HL,BC
        EX	DE,HL
        LD	(HL),B
        DEC	HL
        LD	(HL),C
        JR	POK
TST	PUSH	HL
        PUSH	DE
        EX	DE,HL
        LD	DE,-240
CHCO	LD	A,H
        CP	#D0
        JP	M,RETU
        JR	NZ,NICH
        LD	A,L
        CP	10
        JP	P,NICH
        CP	0
        JP	M,NICH
        LD	A,255
        JR	POP
NICH	ADD	HL,DE
        JR	CHCO
RETU	LD	A,0
POP	POP	DE
        POP	HL
        RET
TSM	LD	HL,#DC00
        LD	B,64
SLP	CALL	LOAD
        LD	A,D
        CP	0
        JR	Z,SCD
        PUSH	HL
        EX	DE,HL
        LD	DE,-10
        ADD	HL,DE
        LD	(HL),0
        EX	DE,HL
        POP	HL
        CALL	TST
        CP	255
        JR 	Z,DS
        PUSH	HL
        EX	DE,HL
        LD	DE,-10
        ADD	HL,DE
        EX	DE,HL
        POP	HL
        LD	A,(DE)
        CP	0
        JR	NZ,DS
        CALL	TST
        CP	255
        JR	Z,DS
        LD	A,139
        LD	(DE),A
SSTO	LD	(HL),D
        DEC	HL
        LD	(HL),E
        INC	HL
SCD	INC	HL
        DJNZ 	SLP
        RET
DS	LD	DE,0
        JR	SSTO
CHECK	PUSH	HL
        LD	HL,(#DA02)
        LD	A,(HL)
        CP	0
        JP	Z,PARE
        CP	133
        JP	Z,PARE
        CP	10
        JP	Z,THVOR
YLF	LD	HL,(#DA02)
        LD	(HL),135
        CALL	PRINT
        LD	E,0
        LD	D,8
L91	LD	HL,#5800
        LD	BC,768
L90	LD	A,(HL)
        AND	199
        ADD	A,E
        LD	(HL),A
        INC	HL
        DEC	BC
        LD	A,B
        OR	C
        JR	NZ,L90
        LD	A,E
        ADD	A,8
        LD	E,A
        LD	C,100
        SLA	A
        ADD	A,12