6.1 Write a program to perform Multiplication of two 8 bit numbers.

Objective:

1. To understand the multiplication using repeated addition
2. To develop flowchart for multiplication using addition process
3. To develop 8085 assembly program for multiplication of two 8-bit numbers
4. To analyse and debug the assembly program

Algorithm

1. Load multiplicand in one register say Register B
2. Load multiplier in register C
3. Clear accumulator
4. Add accumulator and register B
5. decrement count (multiplier value)
6. go to step-4 and repeat if count not zero
7. stop

Program for multiplying two 8-bit numbers

Addr	Opcode	Operands	Label	mnemonic	Remarks
4200	C3	06 042		jmp start
	;data
4203			multiplicand:	db 12
4204		08 (1 bytes)	multiplier:	db 8
4205			product:	ds 1
	;code
4206	00		start:	nop
4207	3A	03 042		LDA multiplicand
420A	47			MOV B, A	Save multiplicand in B
420B	3A	04 042		LDA multiplier
420E	4F			MOV C, A	; save multiplier in C
420F	AF			XRA A	; clear Acc
4210	00		again:	nop
4211	80			ADD B	; A= A+B
4212	0D			DCR C	;decrement count/multiplier
4213	C2	10 42		JNZ again	; repeat if not zero
4216	32	05 042		STA product	; save product
4219	76			hlt

Output:

Example-6.2: Write the multiplication table of a number

Aim : to develop assembly program for 8085 microprocessor to find multiplication table of a number

Objective

1. To understand the multiplication using repeated addition
2. To develop flowchart for multiplication using addition process
3. To develop 8085 assembly program for multiplication of two 8-bit numbers
4. To analyse and debug the assembly program

Steps in writing the program:

1. Load a number in Accumulator

2. Make a copy in register B

3. Set count to 9 in register C

4. Set the HL pair to Point to Y

5. save Acc (1^st data) in Y at index(0)

6. increment pointer to point to next position in Y

7. ADD A with B

8. save Acc at address in HL

9. decrement countable

10. go to step ‘7’ if count not zero

11. stop

Program for generating multiplication table of a number

Address	OP-CODE AND OPERANDS	Label	Mnemonic	Comments
4203	4	X:	DB 4
4204 – 420D		Y:	DS 10	; storage for multiplication table
420E	00	START:	nop
420F	3A,03,42		LDA X	Load accumulator with numble whose multiplication table is to be found
4212	47		MOV B,A	;copy in register B
4213	21,04,42		LXI H, Y	; set memory pointer
4216	77		MOV M, A	; copy the muber at index(0)
4217	0E, 9		MVI C, 9	; set count
4219	80	NEXT:	ADD B	; add number
421A	23		INX H
421B	77		MOV M, A	; save product at next location
421C	0D		DCR C	; decrement count
421D	C2,19.42		JNZ NEXT	; if not zero go to next
4220	76		HLT
RESULT

OUTPUT: