Gyruss: Routine at 80E8

80E8: Main loop

Used by the routines at switch_player and next_stage.
main_loop	80E8	LD HL,interrupt_flag	Flag set by interrupt routine
main_loop_0	80EB	BIT 0,(HL)	Test flag
	80ED	JR Z,main_loop_0	Wait until set
	80EF	RES 0,(HL)	Clear flag
	80F1	CALL $1FDC	READ_REGISTER (read VDP status)
	80F4	CALL display_stars	Display stars
	80F7	CALL control_ship	Control ship
	80FA	CALL process_sprites	Process sprites
	80FD	CALL $1FDC	READ_REGISTER
	8100	CALL handle_collisions	Handle collisions
	8103	CALL create_or_display_mines
	8106	CALL $1FDC	READ_REGISTER
	8109	CALL manage_waves	Manage waves
	810C	CALL create_sprite_from_map_entry	Create sprite from map entry
	810F	CALL $1FDC	READ_REGISTER
	8112	CALL create_laser_fence_or_meteor	Create laser fence
	8115	CALL next_frame_upl_sprites	Upload sprites
	8118	CALL display_center_enemies	Display center enemies
	811B	LD A,(current_player)	Current player
	811E	CALL display_score	Display score
	8121	LD A,(status_flags)	Status flags
	8124	BIT 2,A	Test bit 2
	8126	JP NZ,died	Exit main loop if set
	8129	BIT 1,A	Test bit 1
	812B	JR Z,main_loop	Loop if not set
	812D	LD A,(total_enemies)	Get total enemies
	8130	LD HL,active_enemy_shots	Add enemy shots
	8133	ADD A,(HL)	...
	8134	JP Z,stage_completed	Stage completed when sum is zero
	8137	JR main_loop	Loop