Note: The value '437,500/f' gives the 'half-cycle' length of the note and reducing it by '30.125' allows for '120.5' T states in which to actually produce the note and adjust the counters etc.
The values can now be transferred to the required registers.

		CALL	1E99,FIND-INT2	The 'timing loop' value is
				compressed into the BC
		PUSH	BC	register pair; and saved.

Note: If the timing loop value is too large then an error will occur (returning via ERROR-1); thereby excluding 'pitch' values of '+70 to +127'.

		CALL	1E99,FIND-INT2	The 'f*t' value is compressed
				into the BC register pair.
		POP	HL	Move the 'timing loop' value to
				the HL register pair.
		LD	D,B	Move the 'f*t' value to the
		LD	E,C	DE register pair.

However before making the 'beep' test the value 'f*t'.

		LD	A,D	Return if 'f*t' has given the
		OR	E	result of 'no cycles'
		RET	Z	required.
		DEC	DE	Decrease the cycle number and
		JP	03B5,BEEPER	jump to the BEEPER subroutine
				(making, at least, one pass).

Report B - interget out of range

046C	REPORT-B	RST	0008,ERROR-1	Call the error handling
		DEFB	+0A	routine.

THE 'SEMI-TONE' TABLE
This table holds the frequencies of the twelve semi-tones in an octave.

			frequency hz.	note
046E	DEFB	+89,+02,+D0,+12,+86	261.63	C
	DEFB	+89,+0A,+97,+60,+75	277.18	C#
	DEFB	+89,+12,+D5,+17,+1F	293.66	D
	DEFB	+89,+1B,+90,+41,+02	311.12	D#
	DEFB	+89,+24,+D0,+53,+CA	329.63	E
	DEFB	+89,+2E,+9D,+36,+B1	349.23	F
	DEFB	+89,+38,+FF,+49,+3E	369.99	F#
	DEFB	+89,+43,+FF,+6A,+73	392	G
	DEFB	+89,+4F,+A7,+00,+54	415.30	G#
	DEFB	+89,+5C,+00,+00,+00	440	A
	DEFB	+89,+69,+14,+F6,+24	466.16	A#
	DEFB	+89,+76,+F1,+10,+05	493.88	B

THE 'PROGRAM NAME' SUBROUTINE (ZX81)
The following subroutine applies to the ZX81 and was not removed when the program was rewritten for the SPECTRUM.

04AA	DEFB	+CD,+FB,+24,+3A
	DEFB	+3B,+5C,+87,+FA
	DEFB	+8A,+1C,+E1,+D0
	DEFB	+E5,+CD,+F1,+2B
	DEFB	+62,+6B,+0D,+F8
	DEFB	+09,+CB,+FE,+C9