Question

A block of data is stored in memory location from C101H to C10AH. Write an Assembly Language Program to transfer the block in reverse order to memory location C200H and onward.

Answer 1

        LXI H, C10AH      ; HL points to last source location
        LXI D, C200H      ; DE points to destination start
        MVI C, 0AH        ; Counter = 10 bytes

LOOP:   MOV A, M          ; Copy data from source to accumulator
        STAX D            ; Store data at destination
        DCX H             ; Move to previous source address
        INX D             ; Move to next destination address
        DCR C             ; Decrement counter
        JNZ LOOP          ; Repeat until all bytes are transferred

        HLT               ; Stop program