Booty: Routine at 54735

54735: Menu Keypress

Used by the routine at TitleScreen.
Use FRAMES as a timer.
MenuKeypress	54735	LD BC,0	Reset *FRAMES to 0000.
	54738	LD (23672),BC	Reset *FRAMES to 0000.
This entry point is used by the routine at ToggleMusic.
MenuKeypress_Loop	54742	LD BC,(23672)	BC=*FRAMES.
	54746	LD A,B	Jump to DemoMode if the timer held by FRAMES is up.
	54747	CP 4
	54749	JP Z,DemoMode
	54752	CALL SmallPause	Call SmallPause (presumably to debounce).
Fetch the players pressed key (if any) and handle it. No keys being pressed returns a 255 response.
	54755	CALL 654	Call KEY_SCAN.
	54758	LD A,E	Jump to ToggleMusic if the fire button has been pressed.
	54759	CP 16
	54761	JP Z,ToggleMusic
	54764	CP 255	Return if any button has been pressed.
	54766	RET NZ	Return if any button has been pressed.
	54767	LD A,(23530)	Jump to MenuKeypress_Kempston if *ControlMethod is set to Kempston joystick (12).
	54770	CP 12
	54772	JP Z,MenuKeypress_Kempston
	54775	JR MenuKeypress_Loop	Jump to MenuKeypress_Loop.
Handle checking if the player has pressed fire on their Kempston joystick.
MenuKeypress_Kempston	54777	IN A,(31)	Read from the Kempston joystick port.
	54779	AND %00010000	Jump to MenuKeypress_Loop if fire has not been pressed.
	54781	JR Z,MenuKeypress_Loop	Jump to MenuKeypress_Loop if fire has not been pressed.
	54783	LD A,35	A=35.
	54785	RET	Return.