EXX		H'L'HL.
311B	NO-ADD	EXX		Whether multiplicand was added
		RR	H	or not, shift result right in
		RR	L	H'L'HL, i.e. the shift is done by
		EXX		rotating each byte with carry, so
		RR	H	that any bit that drops into the
		RR	L	carry is picked up by the next
				byte, and the shift continued
				into B'C'CA.
3125	STRT-MLT	EXX		Shift right the multiplier in
		RR	B	B'C'CA (see FETCH-TWO &
				above).
		RR	C	A final bit dropping into the
		EXX		carry will trigger another add of
		RR	C	the multiplicand to the result.
		RRA
		DJNZ	3114,MLT-LOOP	Loop 33 times to get all the bits.
		EX	DE,HL	Move the result from:
		EXX
		EX	DE,HL	H'L'HL to D'E'DE.
		EXX
Now add the exponents together.
		POP	BC	Restore the exponents - M1
				& N1.
		POP	HL	Restore the pointer to the
				exponent byte.
		LD	A,B	Get the sum of the two
		ADD	A,C	exponent bytes in A, and the
				correct carry.
		JR	NZ,313B,MAKE-EXPT	If the sum equals zero then clear
		AND	A	the carry; else leave it
				unchanged.
313B	MAKE-EXPT	DEC	A	Prepare to increase the
		CCF		exponent by Hex.80.
The rest of the subroutine is common to both MULTIPLICATION and DIVISION.
313D	DIVN-EXPT	RLA		These few bytes very cleverly
		CCF		make the correct exponent
				byte.
		RRA		Rotating left then right gets the
				exponent byte (true exponent
				plus Hex.80) into A.
		JP	P,3146,OFLW1-CLR	If the sign flag is reset, no report
				of arithmetic overflow needed.
		JR	NC,31AD,REPORT-6	Report the overflow if carry
				reset.
		AND	A	Clear the carry now.
3146	OFLW-1-CLR	INC	A	The exponent byte is now com-
		JR	NZ,3151,OFLW2-CLR	plete; but if A is zero a further
		JR	C,3151,OFLW-2-CLR	check for overflow is needed.
		EXX		If there is no carry set and the
		BIT	7,D	result is already in normal form
		EXX		(bit 7 of D' set) then there is
		JR	NZ,31AD,REPORT-6	overflow to report; but if bit 7
				of D' is reset, the result in just in
				range, i.e. just under 2**127.
3151	OFLW2-CLR	LD	(HL),A	Store the exponent byte, at last.
		EXX		Pass the fifth result byte to A
		LD	A,B	for the normalisation sequence,
		EXX		i.e. the overflow from L into B'.