stack segment stack'stack'
      dw 32 dup(?)
stack ends
data segment
WA DW 58AEH
BA DB ?
data ends
code segment
begin proc far
      assume ss:stack,cs:code,ds:data
      push ds
      sub ax,ax
      push ax
      mov ax,data
      mov ds,ax
      MOV AH,1
      INT 21H
      SUB AL,30H
      MOV CL,4
      MUL CL
      MOV CL,AL
      MOV BX,WA
      SHR BX,CL
      AND BL,0FH
      MOV BA,BL
      ret
begin endp
code ends
     end begin