Computer-Organization-and-Assembly-Language/p1code4.asm at main · LubabaKhalid/Computer-Organization-and-Assembly-Language · GitHub

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TITLE AL-004 : An AL Program to read two digits whose sum is less than 0,     now subtract instead of adding
              ; computes and display their sum (without using variables).

 .MODEL SMALL
 .STACK 100H

 .DATA
    PROMPT_1  DB  'Enter the First digit : $'
    PROMPT_2  DB  'Enter the Second digit : $'
    PROMPT_3  DB  'difference  of First and Second digit : $'

 .CODE
   MAIN PROC
     MOV AX, @DATA                ; initialize DS
     MOV DS, AX

     LEA DX, PROMPT_1             ; load and display the PROMPT_1
     MOV AH, 9
     INT 21H

     MOV AH, 1                    ; read a character\digit
     INT 21H

     MOV BL, AL                   ; save First digit in BL in ASCII code
     SUB BL, 30H

     MOV AH, 2                    ; carriage return
     MOV DL, 0DH
     INT 21H

     MOV DL, 0AH                  ; line feed
     INT 21H


     LEA DX, PROMPT_2             ; load and display the PROMPT_2
     MOV AH, 9
     INT 21H

  MOV DL, 0AH                  ; line feed    now agin use the line feed ofr more readibility
     INT 21H

     MOV AH, 1                    ; read a character
     INT 21H

     MOV BH, AL                   ; save Second digit in BH in ASCII CODE
     SUB BH, 30H

     MOV AH, 2                    ; carriage return
     MOV DL, 0DH
     INT 21H

     MOV DL, 0AH                  ; line feed
     INT 21H

     LEA DX, PROMPT_3             ; load and display the PROMPT_3
     MOV AH, 9
     INT 21H

     SUB BL, BH                   ; add First and Second digit           now subtarct
     ADD BL, 30H                  ; convert ASCII to DECIMAL code

     MOV AH, 2                    ; display the character
     MOV DL, BL
     INT 21H

     MOV AH, 4CH                  ; return control to DOS
     INT 21H
   MAIN ENDP
 END MAIN