8085 program to swap two 8-bit numbers

In this program we will see how to swap two numbers.

Problem Statement

Write 8085 Assembly language program to swap two 8-bit number stored at location 8000Hand 8001H.

Discussion

In 8085, there is an instruction XCHG. Using this we can swap the contents of DE and HL values. We are taking the numbers and storing them into H and D, then using XCHG the contents are swapped.

Input

Address	Data
. . .	. . .
8000	CD
8001	34
. . .	. . .

Flow Diagram

Program

Address	HEX Codes	Mnemonics	Comments
F000	3A, 00, 80	LDA 8000H	Load the first number into A
F003	67	MOV H, A	Store the number into H
F004	3A, 01, 80	LDA 8001H	Load the second number into A
F007	57	MOV D, A	Store the number into D
F008	EB	XCHG	Exchange DE and HL
F009	7C	MOV A, H	Take H content to A
F00A	32, 00, 80	STA 8000H	Store the first number after swap
F00D	7A	MOV A, D	Take D content to A
F00E	32, 01, 80	STA 8001H	Store the second number after swap
F011	76	HLT	Terminate the program