Question

Need help understanding what to do in this lab!!

INSTRUCTIONS:b Write an assembler program that will calculate the factorial of an integer value inputted by the user. Your program should detect if an overflow occurs. If no overflow occurred, then print out the value of the factorial otherwise print out a message indicating that an overflow occurred.

COMMENTS ARE GREATLY APPRECIATED SO I CAN UNDERSTAND WHAT IS DONE!!

Answer 1

DATA SEGMENT
NUM DB ?
FACT DB 1H
RES DB 10 DUP ('$')
MSG1 DB "ENTER NUMBER : $"
MSG2 DB 10,13,"RESULT : $"
DATA ENDS
CODE SEGMENT
ASSUME DS:DATA,CS:CODE
START:
MOV AX,DATA
MOV DS,AX
LEA DX,MSG1
MOV AH,9
INT 21H
MOV AH,1
INT 21H
SUB AL,30H
MOV NUM,AL
MOV AH,0
MOV AL,FACT
MOV CH,0
MOV CL,NUM
LABEL1: MUL CL
LOOP LABEL1
LEA SI,RES
CALL HEX2DEC
LEA DX,MSG2
MOV AH,9
INT 21H
LEA DX,RES
MOV AH,9
INT 21H
MOV AH,4CH
INT 21H
CODE ENDS
HEX2DEC PROC NEAR
MOV CX,0
MOV BX,10
LOOP1: MOV DX,0
DIV BX
ADD DL,30H
PUSH DX
INC CX
CMP AX,9
JG LOOP1
ADD AL,30H
MOV [SI],AL
LOOP2: POP AX
INC SI
MOV [SI],AL
LOOP LOOP2
RET
HEX2DEC ENDP
END START