Program to find out factorial of number in 8086 assembly language

;Program to find out factorial of number in 8086 assembly language

data segment
     number dw 04h
ends

stack segment
    dw   128  dup(0)
ends

code segment
    assume cs:code, ds:data
start:
    ; set segment registers:
    mov ax, data
    mov ds, ax
 
    mov cx,number
    call fact         
    mov ax, 4c00h ; exit to operating system.
    int 21h 
   
    ;procedure for factorial program
    ;assume cx contains input number
    ;assume Dx contains result 
    fact proc near
           cmp cx, 01h
           jne cont
           mov dx,01h
           ret
  cont:    push cx ; for backup
           dec cx  
           call fact 
           pop ax    ; backup of cx ie n
           mul dx    ; n*(n-1)!
           mov dx, ax ; result into dx
           ret                                          
    fact endp
ends

end start ; set entry point and stop the assembler.