8085 program to swap two 8 bit numbers using Direct addressing mode

In this program we will see how to swap two numbers in direct addressing mode.

Problem Statement

Write 8085 Assembly language program to swap two 8-bit number stored at location 8000H and 8001H using direct addressing mode.

Discussion

In this case we are taking the number from memory by using the HL pair. The HL pair is storing the address of the data item. We are taking the first number into B register, and the second number to A register, then storing the content of B to the next position, and storing the value of A into first position.

Input

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

Flow Diagram

Program

Address	HEX Codes	Mnemonics	Comments
F000	21, 00, 80	LXI H,8000H	Point to the first number
F003	46	MOV B,M	Load the first number to B
F004	23	INX H	Point to the next number
F005	7E	MOV A,M	Load the second number into A
F006	70	MOV M,B	Store first number to second position
F007	2B	DCX H	Point to previous location
F008	77	MOV M,A	Store second number to first position
F009	76	HLT	Terminate the program