The Trap Door: Routine at 64921

64921: Build Music Delay Count

Used by the routine at Continue_MenuMusicTick. Build a delay count from the shared phase at 64655.
Build_MusicDelayCount	64921	PUSH AF	Stash AF on the stack.
	64922	LD A,(64655)	Load 64655, complement it, and copy the result into B and C.
	64925	CPL
	64926	LD B,A
	64927	LD C,A
	64928	ADD A,1	Add 1 so a zero phase still yields a positive count.
	64930	SRA A	Divide A by 4 with two arithmetic shifts right.
	64932	SRA A	Divide A by 4 with two arithmetic shifts right.
	64934	LD E,A	Copy the scaled count into E.
	64935	CP 0	If the scaled count is zero, force E to 1.
	64937	JR NZ,Build_MusicDelayCount_Return	If the scaled count is zero, force E to 1.
	64939	INC E
Restore AF and return the delay count.
Build_MusicDelayCount_Return	64940	POP AF	Restore AF from the stack and return.
	64941	RET	Restore AF from the stack and return.