Question

A list of numbers (in hexa) is stored in the memory location range of (0000 – 00FF), we need to subtract $04 from each number of the list. Solve this problem using assembly language, use the Indexed addressing in writing of your program. Store the result of subtracting each number in the same memory location.

Answer 1

mov si,00                             ;;Giving the initial memory location to 0

mov bl,04h                          ;;bl = 4 constant value to subtract

mov cx,00FFh    ;;cx is counter register cx = FF

back:

    mov al,[si]       ;;Moving element in the memory block to al

    sub al,bl           ;;al = ab-4

    mov [si], al;;Storing the result back in memory location

   

    inc si                  ;;incrementing the memory location

    loop back         ;;looping back to start of the loop

hlt                                                           ;;End of the program.