8085 Program to compute LCM

Now let us see a program of Intel 8085 Microprocessor. This program will find the LCM of two8-bit numbers.

Problem Statement

Write 8085 Assembly language program to find LCM of two 8-bit numbers stored at location8000H and 8001H

Discussion

In this program we are reading the data from 8000H and 8001H. By loading the number, we are storing it at C register, and clear the B register. The second number is loaded into Accumulator. Set DE as the 2's complement of BCregister. This DE is used to subtract BC from HL pair.

The method is like this:let us say the numbers are 25 and 15. When we divide the first number by second, and then if there is no remainder, then the first number is the LCM. But for this case the remainder is present. Then we will check the next multiple of 25 to check the divisibility. When the remainder becomes 0, the program terminates and the result is stored.

Input

first input

Address Data
.
.
.
 .
.
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8000 03
8001 07
.
.
.
 .
.
.

second input

Address Data
.
.
.
 .
.
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8000 23
8001 07
.
.
.
 .
.
.

Flow Diagram

Program

Address HEX Codes Labels Mnemonics Comments
F000 21, 00, 80
LXI H, 8000H    Point 8000Hto get first number
F003 4E
MOV C, M Load memory element to C
F004 06, 00
MVI B, 00H   Clear B register
F006 23
INX H    Point to next location
F007 7E
MOV A, M Load second number to Acc
F008 2F
CMA ComplementAcc
F009 5F
MOV E, A Load 1's complemented form of A to E
F00A 16, FF
MVI D, FFH   Load 1's complemented form of 00H
F00C 13
INX D    Increase DEregister pair
F00D 21, 00, 00
LXI H, 0000H    Load 0000Hinto HL pair
F010 09 NEXT DAD B    Add BC with HL
F011 22, 50, 80
SHLD 8050H   Store HL content into 8050H
F014 19 LOOP DAD D    Add DE withHL
F015 D2, 20, F0
JNC SKIP     When CY = 0,jump to SKIP
F018 7C
MOV A, H Get H content to A
F019 B5
ORA L    OR L with A
F01A CA, 26, F0
JZ EXIT When HL is0000, jump to EXIT
F01D C3, 14, F0
JMP LOOP     Jump to Loop
F020 21, 50, 80 SKIP LHLD 8050H   Load HL from8050H
F023 C3, 10, F0
JMP NEXT     Jump to NEXT
F026 2A, 50, 80 EXIT LHLD 8050H   Store HL pair as LCM
F029 76
HLT Terminate the program


Output

first output

Address Data
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.
.
 .
.
.
8050 15
8051 00
.
.
.
 .
.
.

second output

Address Data
.
.
.
 .
.
.
8050 3B
8051 01
.
.
.
 .
.
.
Updated on: 2019-07-30T22:30:24+05:30

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