LD	A,H	Fetch the 'parity matching'
		XOR	L	byte and include the new byte.
		LD	H,A	Save it once again.
Passes round the loop are made until the 'counter' reaches zero. At that point the 'parity matching' byte should be holding zero.
		LD	A,D	Make a further pass if the DE
		OR	E	register pair does not hold
		JR	NZ,05A9,LD-LOOP	zero.
		LD	A,H	Fetch the 'parity matching'
				byte.
		CP	+01	Return with the carry flat set
		RET		if the value is zero.
				(Carry flag reset if in error.)

THE 'LD-EDGE-2' AND 'LD-EDGE-1' SUBROUTINES
These two subroutines form the most important part of the LOAD/VERIFY operation.
	The subroutines are entered with a timing constant in the B register, and the previous border colour and 'edge-type' in the C register.
	The subroutines return with the carry flag set if the required number of 'edges' have been found in the time allowed; and the change to the value in the B register shows just how long it took to find the 'edge(s)'.
	The carry flag will be reset if there is an error. The zero flag then signals 'BREAK pressed' by being reset, or 'time-up' by being set.
	The entry point LD-EDGE-2 is used when the length of a complete pulse is required and LD-EDGE-1 is used to find the time before the next 'edge'.

05E3	LD-EDGE-2	CALL	05E7,LD-EDGE-1	In effect call LD-EDGE-1 twice;
		RET	NC	returning in between if there
				is an error.
05E7	LD-EDGE-1	LD	A,+16	Wait 358 T states before
05E9	LD-DELAY	DEC	A	entering the sampling loop.
		JR	NZ,05E9,LD-DELAY
		AND	A

The sampling loop is now entered. The value in the B register is incremented for each pass; 'time-up' is given when B reaches zero.

05ED	LD-SAMPLE	INC	B	Count each pass.
		RET	Z	Return carry reset & zero set if
				'time-up'.
		LD	A,+7F	Read from port +7FFE.
		IN	A,(+FE)	i.e. BREAK & EAR.
		RRA		Shift the byte.
		RET	NC	Return carry reset & zero reset
				if BREAK was pressed.
		XOR	C	Now test the byte against the
		AND	+20	'last edge-type'; jump back
		JR	Z,05ED,LD-SAMPLE	unless it has changed.

A new 'edge' has been found within the time period allowed for the search. So change the border colour and set the carry flag.

		LD	A,C	Change the 'last edge-type'
		CPL		and border colour.
		LD	C,A
		AND	+07	Keep only the border colour.
		OR	+08	Signal 'MIC off'.
		OUT	(+FE),A	Change the border colour (RED/
				CYAN or BLUE/YELLOW).
		SCF		Signal the successful search
		RET		before returning.

Note: The LD-EDGE-1 subroutine takes 465 T states, plus an additional 58 T states for each unsuccessful pass around the sampling loop.