Moonlight Madness: Routine at E666

E666: Play Tune

Used by the routines at Handler_Interrupts and Animate_Introduction. Plays one note from Data_TuneStream / Data_TuneStreamCopy through the speaker. BC is the note length (1106 in-game, 0A14 on the introduction).

Play_Tune	E666	LD A,($647C)	Jump to JumpTable_Delay if *SkipDelayFlag is set.
	E669	OR A
	E66A	JP NZ,JumpTable_Delay
	E66D	LD HL,($6469)	Read the next Data_TuneStream byte, wrapping at FF.
	E670	LD A,(HL)
	E671	CP $FF
	E673	JR NZ,Play_Tune_StorePitch
	E675	LD HL,$B491
	E678	LD ($646B),HL
	E67B	LD HL,$B370
	E67E	LD A,(HL)
Play_Tune_StorePitch	E67F	INC HL	Store the pitch and read the matching Data_TuneStreamCopy duration.
	E680	LD ($6469),HL
	E683	LD ($646D),A
	E686	LD HL,($646B)
	E689	LD A,(HL)
	E68A	INC HL
	E68B	LD ($646B),HL
	E68E	LD D,A
	E68F	LD E,$01
	E691	LD A,($646D)
	E694	LD H,A
	E695	LD L,$01
	E697	DEC A	Jump to Play_Tune_Rest if this is a rest.
	E698	JP NZ,Play_Tune_Tone
	E69B	LD A,D
	E69C	DEC A
	E69D	JR Z,Play_Tune_Rest
Play_Tune_Tone	E69F	LD A,($641D)	Load the border colour and set the half-cycle counters.
	E6A2	EX AF,AF'
	E6A3	LD A,($641D)
	E6A6	LD IXh,D
	E6A8	LD D,$10
Play_Tune_Toggle	E6AA	NOP	Toggle the speaker and loop back through Play_Tune_Hold and Play_Tune_Release.
	E6AB	NOP
	E6AC	EX AF,AF'
	E6AD	DEC E
	E6AE	OUT ($FE),A
	E6B0	JR NZ,Play_Tune_Hold
	E6B2	LD E,IXh
	E6B4	XOR D
	E6B5	EX AF,AF'
	E6B6	DEC L
	E6B7	JP NZ,Play_Tune_Release
Play_Tune_Half	E6BA	OUT ($FE),A	Reload the duration and loop back to Play_Tune_Toggle.
	E6BC	LD L,H
	E6BD	XOR D
	E6BE	DJNZ Play_Tune_Toggle
	E6C0	DEC C
	E6C1	JP NZ,Play_Tune_Toggle
	E6C4	RET
Play_Tune_Hold	E6C5	JR Z,Play_Tune_Hold	Hold until the inner count expires.
	E6C7	EX AF,AF'
	E6C8	DEC L
	E6C9	JP Z,Play_Tune_Half
Play_Tune_Release	E6CC	OUT ($FE),A	Toggle the speaker on the release half-cycle.
	E6CE	NOP
	E6CF	NOP
	E6D0	DJNZ Play_Tune_Toggle
	E6D2	DEC C
	E6D3	JP NZ,Play_Tune_Toggle
	E6D6	RET
Play_Tune_Rest	E6D7	PUSH HL	Waste time for a rest.
	E6D8	LD HL,$0000
	E6DB	SRA (HL)
	E6DD	SRA (HL)
	E6DF	SRA (HL)
	E6E1	NOP
	E6E2	POP HL
	E6E3	DEC B
	E6E4	JP NZ,Play_Tune_Rest
	E6E7	DEC C
	E6E8	JP NZ,Play_Tune_Rest
	E6EB	RET