Program to multiply two 16-bit binary numbers in 8085 Microprocessor

Here we will see one program for Intel 8085 Microprocessor. This program will calculate the multiplication of two 16-bit numbers.

Problem Statement −

Write an 8085 Assembly language program to multiply two 16-bit numbers stored at 8000H - 8001H and 8002H - 8003H.

Discussion −

This program takes the 16 bit data from memory location 8000H – 8001H and 8002H – 8003H. The 32 bit results are stored at location 8050H – 8053H.

Here we have tested with two 16 bit numbers. The results are as follows.

1111H × 1111H = 01234321H

1C24H × 0752H = 00CDFF88H

Input

first input

second input

Address	HEX Codes	Labels	Mnemonics	Comments
F000	31, 00, 20		LXI SP,2000H	Initialize Stack pointer
F003	2A, 00, 80		LHLD 8000H	Load 16-bit data from 8000H - 8001H
F006	EB		XCHG	Exchange the data from HL and DE
F007	2A, 02, 80		LHLD 8002H	Load second 16-bit number
F00A	E5		PUSH H	Push HL pair into stack
F00B	C1		POP B	Load BC with HL pair content from stack
F00C	21, 00, 00		LXI H,0000H	Clear HL pair
F00F	22, 52, 80		SHLD 8052H	Store 0000H as LS 2-bytes of the result
F012	19	LOOP	DAD D	Add first number to HL pair
F013	D2, 1F, F0		JNC NINC	if CY = 0, jump to NINC
F016	E5		PUSH H	Push HL into Stack
F017	2A, 52, 80		LHLD 8052	Load HL pair from LS 2-bytes of the result
F01A	23		INX H	Increase HL pair
F01B	22, 52, 80		SHLD 8052H	Store HL pair as LS 2-bytes of the result
F01E	E1		POP H	Pop stack content to HL pair
F01F	0B	NINC	DCX B	Decrease BC register pair
F020	78		MOV A,B	Load B to A
F021	B1		ORA C	OR C with A
F022	C2, 12, F0		JNZ LOOP	When Z = 0, jump to LOOP
F025	22, 50, 80		SHLD 8050H	Store HL pair to 8050H
F028	76		HLT	Terminate the program