DATA SEGMENT
A DB 5
DATA ENDS
CODE SEGMENT
         ASSUME DS:DATA,CS:CODE
START:
      MOV AX,DATA
      MOV DS,AX
      MOV AH,00
      MOV AL,A
 L1:  DEC A
      MUL A
      MOV CL,A
      CMP CL,01
      JNZ L1
      MOV AH,4CH
      INT 21H 
CODE ENDS
END START

;OUTPUT:->
;-G CS: 001B
;
;AX=0078  BX=0000  CX=0001  DX=0000  SP=0000  BP=0000  SI=0000  DI=0000
;DS=0BA8  ES=0B98  SS=0BA8  CS=0BA9  IP=001B   NV UP EI PL ZR NA PE NC
;0BA9:001B B44C          MOV     AH,4C