One's Compliment

To find 1's compliment without complimenting the accumulator or using XOR in 8085 Assembly Language

LDA 0000H
MVI B,09H
LOOP: RAR
CMC
DCR B
JNZ LOOP
STA 0001H
HLT

M#1

Two 8-bits numbers (say x,y) are stored in memory location 0000H and 0001H.This program finds the value of 2(x*y) and stores the result at 0002H and 0003H.

First we add x with itself y times to get x*y, the sum is stored in register D and carry in register E(if any). Then the byte is register D is added twice and if any carry is generated is stored in register C, finally the carry in register E is added twice withe itself and then with C to get the result

LXI H,0000H

MOV B,M

INX H

MOV C,M

XRA A

MOV D,A

MOV E,A

LOOP: ADD B

JNC SKIP

INR E

SKIP: DCR C

JNZ LOOP

MOV D,A

XRA A

MOV C,A

MVI B,02H

LOOP1: ADD D

JNC SKIP1

INR C

SKIP1: DCR B

JNZ LOOP1

STA 0002H

MVI B,02H

XRA A

LOOP2: ADD E

DCR B

JNZ LOOP2

ADD C

STA 0003H

HLT