Everyone's a Wally: Routine at B505

B505: Play Theme Music

Used by the routine at ThemeMusic.
Play_ThemeMusic	B505	LD A,($B4EA)	If Flag_ThemeMusic_KeyChange is zero jump to Play_ThemeMusic_KeyChange.
	B508	OR A
	B509	JR Z,Play_ThemeMusic_KeyChange
	B50B	LD H,B	H=B.
	B50C	LD L,C	L=C.
	B50D	JR Play_ThemeMusic_Sound	Jump to Play_ThemeMusic_Sound.
Play_ThemeMusic_KeyChange	B50F	LD H,B	H=B.
	B510	LD L,C	L=C.
	B511	SRA B
	B513	RR C
	B515	ADD HL,BC	HL+=BC.
	B516	SRA B
	B518	RR C
	B51A	ADD HL,BC	HL+=BC.
	B51B	SRA B
	B51D	RR C
	B51F	ADD HL,BC	HL+=BC.
Flip speaker on (set bit 4).
Play_ThemeMusic_Sound	B520	LD A,%00010000	A=10 (speaker on = bit 4).
	B522	OUT ($FE),A	A=10 (speaker on = bit 4).
	B524	CALL Handler_GameMenuInput	Call Handler_GameMenuInput.
Flip speaker off (unset bit 4).
	B527	XOR A	A=00 (speaker off).
	B528	OUT ($FE),A	A=00 (speaker off).
	B52A	PUSH BC	Stash BC on the stack.
	B52B	LD B,H	B=H.
	B52C	LD C,L	C=L.
	B52D	CALL Handler_GameMenuInput	Call Handler_GameMenuInput.
	B530	POP BC	Restore BC from the stack.
	B531	DEC DE	Decrease DE by one.
	B532	LD A,D	Jump to Play_ThemeMusic_Sound until DE is zero.
	B533	OR E
	B534	JR NZ,Play_ThemeMusic_Sound
	B536	RET	Return.