LAB 3 (Take two input and print the two digit and their subtraction)

; Write a program to
 ; (a) display a "?",
 ; (b) read two decimal digits whose sum "is less than 10
 ; (c) display them and their subtraction on the next line, with an appropriate message Simple Assembly Language Solution.



.MODEL SMALL   ; IN THIS COURSE ALL MODEL ARE SMALL
.STACK 100H    ; WE ALWAYS USE STACK 100H


.DATA     ; DATA SEGMENT

    STR1 DB 0AH,0DH,'THE SUBTRRACTION OF '     ; PRINT A NEW LINE AFTER TAKING INPUT SO WE USE 0AH,0DH
    FIRSTNUM DB ?                     ; TAKE A VARIABLE WHERE WE TAKE FIRST NUMBER
    STR2 DB ' AND '                   ; ASSIGN A STRING IN STR 2
    SECONDNUM DB ?                    ; TAKING SENOCD NUMBER
    STR3 DB ' IS '                    ; ASSIGN ANOTHER STRING IN STR3
    ANS DB ?                          ; TAKE A VARIABLE WHERE WE WILL PUT OUT SUMMATION, AND DO NOT END THE STRING BY $ SIGN
    STR4 DB ' $'                      ; ASSIGN $ HERE SO ALL AVOBE STRING ARE PRINT TOGETHER



.CODE

MAIN PROC       ; MAIN CODE START HERE

    ;PROGRAMME SEGMENT PREFIX
    MOV AX,@DATA
    MOV DS,AX    ; INITILATION OF DS


    MOV AH,2     ; PRINT SOME STRING
    MOV DL,3FH   ; PRINT ? SIGN, WE CAN ALSO PRINT IT BY       MOV DL,'?'
    INT 21H      ; INTRUPT THE WORK

    MOV AH,1            ; TAKING SOME INPUT
    INT 21H             ; INTRUPT THE WORK
    MOV BL,AL           ; IF WE TAKE INPUT GENERALY GOES TO AL SO WE MOVE THE INPUT VALUE INTO BL.
    MOV FIRSTNUM,AL     ; TAKE THE FIRST NUMBER INTO REGISTER
    INT 21H             ; INTRUPT THE WORK
    MOV SECONDNUM,AL    ; TAKE THE SECOND NUMBER INTO REGISTER

    SUB BL,AL      ; HERE WE SUBTRACT BL AND AL
    ADD BL,30H     ; TO COVERT ASCII TO DECIMAL WE ADDED 30 FROM SUBTRACT VALUE     BL + 30 = BL ,   NOW IT IS DECIMAL.. CHECK ASCII TO  UNDERSTAND BETTER
    MOV ANS,BL     ; NOW MOVE THE VALUE INTO ANSWER

    MOV AH,9      ; PRINT STRING
    LEA DX,STR1   ; VARIABLE PRINTING FIRST TO LAST  BECAUSE WE USE $ AT LAST. SO IT PRINT FIRST TO LAST
    INT 21H       ; INTRUPT THE WORK



    MOV AX,4CH ; TERMINATED THE CODE AND EXIT
    INT 21H
    MAIN ENDP
END MAIN