The remainder of the subroutine deals with normalisation and is common to all the arithmetic routines.
3155	TEST-NORM	JR	NC,316C,NORMALISE	If no carry then normalise now.
		LD	A,(HL)	Else, deal with underflow (zero
		AND	A	result) or near underflow
3159	NEAR-ZERO	LD	A,+80	(result 2**-128):
		JR	Z,315E,SKIP-ZERO	return exponent to A, test if A
315D	ZERO-RSLT	XOR	A	is zero (case 2**-128) and if so
315E	SKIP-ZERO	EXX		produce 2**-128 if number is
		AND	D	normal; otherwise produce zero.
		CALL	2FFB,ZEROS-4/5	The exponent must then be set
		RLCA		to zero (for zero) or 1 (for
				2**-128).
		LD	(HL),A	Restore the exponent byte.
		JR	C,3195,OFLOW-CLR	Jump if case 2**-128.
		INC	HL	Otherwise, put zero into second
		LD	(HL),A	byte of result on the calculator
		DEC	HL	stack.
		JR	3195,OFLOW-CLR	Jump forward to transfer the
				result.
The actual normalisation operation.
316C	NORMALISE	LD	B,+20	Normalise the result by up to 32
316E	SHIFT-ONE	EXX		decimal, Hex.20, shifts left of
		BIT	7,D	D'E'DE (with A adjoined) until
		EXX		bit 7 of D' is set. A holds zero
		JR	NZ,3186,NORML-NOW	after addition so no precision is
		RLCA		gained or lost; A holds the fifth
		RL	E	byte from B' after multiplica-
		RL	D	tion or division; but as only
		EXX		about 32 bits can be correct, no
		RL	E	precision is lost. Note that A is
		RL	D	rotated circularly, with branch
		EXX		at carry .... eventually a random
				process.
		DEC	(HL)	The exponent is decremented
				on each shift.
		JR	Z,3159,NEAR-ZERO	If the exponent becomes zero,
				then number from 2**-129 are
				rounded up to 2**-128.
		DJNZ	316E,SHIFT-ONE	Loop back, up to 32 times.
		JR	315D,ZERO-RSLT	If bit 7 never became 1 then the
				whole result is to be zero.
Finish the normalisation by considering the 'carry'.
3186	NORML-NOW	RLA		After normalisation add back
		JR	NC,3195,OFLW-CLR	any final carry that went into A.
		CALL	3004,ADD-BACK	Jump forward if the carry does
		JR	NZ,3195,OFLW-CLR	not ripple right back.
		EXX		If it should ripple right back
		LD	D,+80	then set mantissa to 0.5 and
		EXX		increment the exponent.
		INC	(HL)	This action may lead to arith-
		JR	Z,31AD,REPORT-6	metic overflow (final case).
The final part of the subroutine involves passing the result to the bytes reserved for it on the calculator stack and resetting the pointers.
3195	OFLOW-CLR	PUSH	HL	Save the result pointer.
		INC	HL	Point to the sign byte in the
				result.
		EXX		The result is moved from its
		PUSH	DE	present registers, D'E'DE, to
		EXX		BCDE; and then to ACDE.