Intel 210200-002 manual Lpi Hl,O

APPENDIX

BENCHMARK: 16-Bit Multiply

PROCESSOR: Z80

;Register	usage
A	Count
DE	Multiplier, Product MSB
BC	Multiplicand
HL	Product LSB

Bytes Cycles

4	~O		LD		DE,(Ml)		;Load	multiplier
4	~O		LD		BC, (M~)		;Load	multiplicand
t	7		LD		A,16		;Load	count
3	10	LPI:	LD		HL,O		;Clear	HL		LSB	left
1	11		ADD		HL,HL		;Shift	product
1	4		EX		HL,DE		;Exchange		MSB	with	LSB
~	71lt		JR		C,MPl		;Jump if carry from LSB
1	11		ADD		HL,HL		;No carry. Shift multiplier left.
3	10		JP		MP~		;Carry.		Shift	multiplier left.
1	11	MP 1:	ADD		HL,HL
1	6	MPt:	INC		HL		;Increment multiplier
1	4		EX		HL,DE		;
~	7Il ~		JR		NC,MP3		;Jump if no carry from multiplier
1	11		ADD		HL,BC		;Add multiplicand to product LSB
~	71l~		JR		NC,MP3		;Jump	if	no carry
1	6	MP3:	INC		DE		;Increment MSB due to Add carry
1	4		DEC		A		;Decrement count
3	10		JP		NZ,LP		;Loop	if	not zero
4	~O		LD		(PRMSB),DE		;Store	product
3	16		LD		(PRLSB) HL
			41	bytes	of	code
			~O	lines	of	code

13 AFN-Ole64A