The Trap Door: Routine at FD10

FD10: Play Menu Music Pulse Tail

Used by the routine at Play_MenuMusicTick. Continuation of the Play_MenuMusic_PulseLoop tone loop when the fine delay is still non-zero. The opening `JR Z` is a never-taken timing pad (entry always has the zero flag clear).
Play_MenuMusic_PulseTail	FD10	JR Z,Play_MenuMusic_PulseTail	Never-taken timing pad (`JR Z`). Fall through with the zero flag clear.
Finish the fine-delay tail and return to the main pulse loop.
Play_MenuMusic_PulseTailBody	FD12	EX AF,AF'	Switch to the alternate accumulator.
	FD13	DEC L	Decrease the coarse delay in L.
	FD14	JP Z,Play_MenuMusic_ReloadCoarse	If the coarse delay expired, jump to Play_MenuMusic_ReloadCoarse.
This entry point is used by the routine at Play_MenuMusicTick. Port write used when the coarse delay is still running.
Play_MenuMusic_PulseTailWrite	FD17	OUT ($FE),A	Write the speaker level to port FE.
	FD19	NOP	Timing pad before the outer count test.
	FD1A	NOP	Timing pad before the outer count test.
	FD1B	DJNZ Play_MenuMusic_PulseLoop	Decrease B and loop to Play_MenuMusic_PulseLoop while the outer count remains.
	FD1D	INC C	Advance the phase counter in C.
	FD1E	JP NZ,Play_MenuMusic_PulseWrite	If the phase remains, jump to Play_MenuMusic_PulseWrite.
	FD21	RET	Return.