Gyruss: Routine at 9E91

9E91: Call play tune, preserve registers

Used by the routines at init_stage_8, stage_completed and perfect_bonus. I:A Index of tune
call_play_tune	9E91	PUSH BC
	9E92	PUSH DE
	9E93	PUSH HL
	9E94	PUSH IX
	9E96	PUSH IY
	9E98	CALL play_tune	Play tune
	9E9B	POP IY
	9E9D	POP IX
	9E9F	POP HL
	9EA0	POP DE
	9EA1	POP BC
	9EA2	RET