Assembly Language Design and Write a FACTORIAL program FYI

Assembly Language:

Design and Write a FACTORIAL program – (FYI / DEFINITION: Its most basic occurrence is the fact that there are n! ways to arrange n distinct objects into a sequence.)

Create a program that will calculate the FACTORIAL of ANY number that is assigned.

Example: 5! (This means FIVE – FACTORIAL.) To calculate this, you start at the original number…in this case, 5.

Calculation: 5 * 4 * 3 * 2 * 1 equals the Result / that is, FIVE FACTORIAL

Solution

INCLUDE io.h

Cr EQU 0ah
Lf EQU 0dh

data SEGMENT
p_n DB cr, lf, \'Enter value n: \',0
p_res DB cr, lf, \'The factorial of given number is: \',0
tmpstr DW 40 DUP (?)
data ENDS

code SEGMENT
ASSUME cs:code, ds:data
start: mov ax, data
mov ds, ax
;input number
output p_n
inputs tmpstr, 10
atoi tmpstr
;initialize
mov bx, ax
mov ax, 01h
; find factorial
Fact_loop: imul bx
dec bx
jnz Fact_loop
;Display factorial
output p_res
itoa tmpstr, ax
output tmpstr

EndQ: mov al, 00h
mov ah, 4ch
int 21h
code ENDS
END start

===================================================================

Outptut:

Enter value n:
5
The factorial of given number is 120