Add/Subtract Single Digit Number in Assembly Language

Well, I'm not that good with this. I just want to share this "simple" arithmetic done in assembly programming.

The program will:

• Ask the user to choose addition or subtraction 
• Ask the user to input the 1st single digit number
• Ask the user to input the 2nd single digit number
• Show the result

The program won't accept any other value except number. It will also shows (-) negative sign just like the image above.

Anyway, here's the code below:



.MODEL SMALL .STACK 100h .DATA SELECTION DB 13,10,'1.)ADDITION ',10,'2.) SUBTRACTION',10,'3.) EXIT',10,10,'SELECT: $' FIRST_NUMBER DB 13,10,10,'ENTER FIRST NUMBER:$' SECOND_NUMBER DB 13,10,'ENTER SECOND NUMBER:$' msgEr DB 13,10,13,10,'ERROR, TRY AGAIN! $' ANSWER DB 13,10,10,'THE SUM IS:$' ANSWER2 DB 13,10,10,'THE DIFFERENCE IS: $' .CODE start: mov ax,@data mov ds,ax mov dx,OFFSET SELECTION mov ah,9 int 21h mov ah,1 int 21h cmp al,'1' jz Addition cmp al,'2' jz Subtraction cmp al,'3' jz Done error: lea dx,msgEr mov ah,09h int 21h jmp start Done: mov ah,4ch int 21h Addition: mov dx,OFFSET FIRST_NUMBER mov ah,9 int 21h mov ah,1 int 21h MOV BL,AL AND BL,0Fh mov dx,OFFSET SECOND_NUMBER mov ah,9 int 21h mov ah,1 int 21h mov ah,0 ADD AL,BL AAA OR AX,3030H MOV Bx,AX mov dx,OFFSET ANSWER mov ah,9 int 21h ;mov dl,Bh ;mov ah,2 ;int 21h mov dl,Bl mov ah,2 int 21h jmp start Subtraction: mov dx,OFFSET FIRST_NUMBER ;prompt to input 1st number mov ah,9 int 21h mov ah,1 int 21h MOV BL,AL AND BL,0Fh cmp al, 0Dh ;Returns je error cmp al, 30h ;0 (ASCII 48) jl error cmp al, 39h ;9 (ASCII 57) jg error mov dx,OFFSET SECOND_NUMBER ;prompt to input 2nd number mov ah,9 int 21h mov ah,1 int 21h MOV BH,AL AND BH,0Fh cmp al, 0Dh ;Returns je error cmp al, 30h ;0 (ASCII 48) jl error cmp al, 39h ;9 (ASCII 57) jg error cmp bh,bl ;compare the two numbers jg Subtraction2 Subtraction1: mov ah,0 SUB BL,AL MOV AL,BL AAS OR AX,3030H MOV Bx,AX mov dx,OFFSET ANSWER2 mov ah,9 int 21h mov dl,Bl mov ah,2 int 21h jmp start Subtraction2: ;negative mov ah,0 SUB AL,BL AAS OR AX,3030H MOV Bx,AX mov dx,OFFSET ANSWER2 mov ah,9 int 21h mov ah, 6 mov dl, 2Dh ;Display the - sign int 21h mov dl,Bl mov ah,2 int 21h jmp start end start
That's all! I'm just happy today! :)