8085 Program to Find the Sum of First N Natural Numbers

In this program we will see how to add first n natural numbers.

Problem Statement

Write 8085 Assembly language program to add first N natural numbers. The value of N is provided.

Discussion

We are getting the value of N from memory location 8000H. We are using the number N as count variable, in each step we are calculating (A + Count) value, and store them into A. After adding them, the count value is decreased,thus the total series is completed.

If the number is 23H(35D), then the sum will be (35*36)/2 = 630 (276H)

Input

Address
 Data
.
.
.
 .
.
.
8000
 23
.
.
.
 .
.
.


Flow Diagram

Program

Address
 HEX Codes
 Labels
 Mnemonics
 Comments
F000
 21, 00, 80

LXI H,8000H
 Point to get the upper limit
F003
 4E

MOV C, M
 Load the upper limit to C
F004
 AF

XRA A
 Clear the A register
F005
 47

MOV B, A
 Also clear B register
F006
 81
 LOOP
 ADD C
 Add C with A
F007
 D2, 0B, F0

JNC SKIP
 If CY = 0,Skip next step
F00A
 04

INR B
 Increase B ifCY = 1
F00B
 0D
 SKIP
 DCR C
 Decrease C by1
F00C
 C2, 06, F0

JNZ LOOP
 Until Z = 1,go to LOOP
F00F
 21, 50, 80

LXI H, 8050H
 Point to the destination address
F012
 77

MOV M, A
 Store the acc content
F013
 23

INX H
 Point to next location
F014
 70

MOV M, B
 Store the MSbyte
F015
 76

HLT
 Terminate the program


Output

Address
 Data
.
.
.
 .
.
.
8050
 76
8051
 02
.
.
.
 .
.
.
Updated on: 2019-07-30T22:30:24+05:30

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