8085 Program to Exchange contents of memory locations 8085 Microprocessor

Program to Exchange contents of memory locations 8085 Microprocessor

Statement: Exchange the contents of memory locations 2000H and 4000H

Program 1:

 LDA 2000H : Get the contents of memory location 2000H into accumulator
 MOV B, A    : Save the contents into B register
 LDA 4000H : Get the contents of memory location 4000Hinto accumulator
 STA 2000H : Store the contents of accumulator at address 2000H
 MOV A, B    : Get the saved contents back into A register
 STA 4000H : Store the contents of accumulator at address 4000H

Program 2:
LXI H 2000H          : Initialize HL register pair as a pointer to memory location 2000H.
LXI D 4000H         : Initialize DE register pair as a pointer to memory location 4000H.
MOV B, M     : Get the contents of memory location 2000H into B register.
LDAX D        : Get the contents of memory location 4000H into A register.
MOV M, A     : Store the contents of A register into memory location 2000H.
MOV A, B     : Copy the contents of B register into accumulator.
STAX D        : Store the contents of A register into memory location 4000H.
HLT              : Terminate program execution.

In Program 1, direct addressing instructions are used, whereas in Program 2, indirect addressing instructions are used.