Question

A block of data stored in memory location from 2600H to 2609H. Write Assembly Language Program to transfer to data block in reverse order starting from memory location 2700H.

Answer 1

        MVI B, 0AH        ; Store 0AH in register B (counter)

        LXI H, 2609H      ; Set HL pair with 2609H (source)
        LXI D, 2700H      ; Set DE pair with 2700H (destination)

CYCLE:  MOV A, M          ; Transfer memory content to accumulator
        STAX D            ; Store accumulator at address pointed by DE

        DCX H             ; Decrement HL pair by 1
        INX D             ; Increment DE pair by 1

        DCR B             ; Decrement counter
        JNZ CYCLE         ; If B ≠ 0, repeat loop

        HLT               ; Stop program