Alien (BUGFIX 1.7): Routine at 40319

Controls frame timing and plays a queued sound effect. Reads the sound- request flag at 33731. If zero, calls the fixed ~36 ms delay at BusyWait — nearly two 50 Hz frames, so the main loop is not interrupt-synced (see the GameEntry header) — and returns. If non-zero, plays a beeper tone by reading 1-KB ROM bytes starting at $0200 and toggling bit 4 of port $FE for each byte; the outer loop runs 255 × 4 iterations with a short delay (D=64 counts) between each toggle. After playback, clears the sound-request flag.

Used by the routines at 36457, 40281 and 43242.

Controls frame timing and plays a queued sound effect. Reads the sound- request flag at 33731. If zero, calls the fixed ~36 ms delay at BusyWait — nearly two 50 Hz frames, so the main loop is not interrupt-synced (see the GameEntry header) — and returns. If non-zero, plays a beeper tone by reading 1-KB ROM bytes starting at $0200 and toggling bit 4 of port $FE for each byte; the outer loop runs 255 × 4 iterations with a short delay (D=64 counts) between each toggle. After playback, clears the sound-request flag. Used by the routines at 36457, 40281 and 43242.
40319	LD A,(33699)	A = sound-request flag (33731)
40322	AND A	any sound queued?
40323	JR NZ,40329	yes: play beeper effect
40325	CALL 36448	no: fixed ~36ms busy-wait
40328	RET
40329	LD HL,512	HL = $0200 (ROM tone data source)
40332	LD D,64	D = inter-toggle delay count
40334	LD B,255	outer loop: 255 iterations
40336	PUSH BC
40337	LD B,4	4 sub-iterations per outer step
40339	PUSH BC
40340	PUSH DE
40341	LD A,(HL)	read ROM byte
40342	INC HL	advance data pointer
40343	AND 16	isolate bit 4 (EAR/MIC output)
40345	OUT (254),A	toggle beeper
40347	DEC D	delay loop
40348	JR NZ,40347
40350	POP DE
40351	POP BC
40352	DJNZ 40339	repeat 4 sub-iterations
40354	POP BC
40355	DJNZ 40336	repeat 255 outer iterations
40357	XOR A
40358	LD (33699),A	clear sound-request flag
40361	RET