/
calculator.asm
211 lines (181 loc) · 5.89 KB
/
calculator.asm
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org 100h
jmp start ; jump over data declaration
msg: db "1-Add",0dh,0ah,"2-Multiply",0dh,0ah,"3-Subtract",0dh,0ah,"4-Divide", 0Dh,0Ah, '$'
msg2: db 0dh,0ah,"Enter First No : $"
msg3: db 0dh,0ah,"Enter Second No : $"
msg4: db 0dh,0ah,"Choice Error $"
msg5: db 0dh,0ah,"Result : $"
msg6: db 0dh,0ah ,'thank you for using the calculator! press any key... ', 0Dh,0Ah, '$'
start: mov ah,9
mov dx, offset msg ;first we will display hte first message from which he can choose the operation using int 21h
int 21h
mov ah,0
int 16h ;then we will use int 16h to read a key press, to know the operation he choosed
cmp al,31h ;the keypress will be stored in al so, we will comapre to 1 addition ..........
je Addition
cmp al,32h
je Multiply
cmp al,33h
je Subtract
cmp al,34h
je Divide
mov ah,09h
mov dx, offset msg4
int 21h
mov ah,0
int 16h
jmp start
Addition: mov ah,09h ;then let us handle the case of addition operation
mov dx, offset msg2 ;first we will display this message enter first no also using int 21h
int 21h
mov cx,0 ;we will call InputNo to handle our input as we will take each number seprately
call InputNo ;first we will move to cx 0 because we will increment on it later in InputNo
push dx
mov ah,9
mov dx, offset msg3
int 21h
mov cx,0
call InputNo
pop bx
add dx,bx
push dx
mov ah,9
mov dx, offset msg5
int 21h
mov cx,10000
pop dx
call View
jmp exit
InputNo: mov ah,0
int 16h ;then we will use int 16h to read a key press
mov dx,0
mov bx,1
cmp al,0dh ;the keypress will be stored in al so, we will comapre to 0d which represent the enter key, to know wheter he finished entering the number or not
je FormNo ;if it's the enter key then this mean we already have our number stored in the stack, so we will return it back using FormNo
sub ax,30h ;we will subtract 30 from the the value of ax to convert the value of key press from ascii to decimal
call ViewNo ;then call ViewNo to view the key we pressed on the screen
mov ah,0 ;we will mov 0 to ah before we push ax to the stack bec we only need the value in al
push ax ;push the contents of ax to the stack
inc cx ;we will add 1 to cx as this represent the counter for the number of digit
jmp InputNo ;then we will jump back to input number to either take another number or press enter
;we took each number separatly so we need to form our number and store in one bit for example if our number 235
FormNo: pop ax
push dx
mul bx
pop dx
add dx,ax
mov ax,bx
mov bx,10
push dx
mul bx
pop dx
mov bx,ax
dec cx
cmp cx,0
jne FormNo
ret
View: mov ax,dx
mov dx,0
div cx
call ViewNo
mov bx,dx
mov dx,0
mov ax,cx
mov cx,10
div cx
mov dx,bx
mov cx,ax
cmp ax,0
jne View
ret
ViewNo: push ax ;we will push ax and dx to the stack because we will change there values while viewing then we will pop them back from
push dx ;the stack we will do these so, we don't affect their contents
mov dx,ax ;we will mov the value to dx as interrupt 21h expect that the output is stored in it
add dl,30h ;add 30 to its value to convert it back to ascii
mov ah,2
int 21h
pop dx
pop ax
ret
exit: mov dx,offset msg6
mov ah, 09h
int 21h
mov ah, 0
int 16h
ret
Multiply: mov ah,09h
mov dx, offset msg2
int 21h
mov cx,0
call InputNo
push dx
mov ah,9
mov dx, offset msg3
int 21h
mov cx,0
call InputNo
pop bx
mov ax,dx
mul bx
mov dx,ax
push dx
mov ah,9
mov dx, offset msg5
int 21h
mov cx,10000
pop dx
call View
jmp exit
Subtract: mov ah,09h
mov dx, offset msg2
int 21h
mov cx,0
call InputNo
push dx
mov ah,9
mov dx, offset msg3
int 21h
mov cx,0
call InputNo
pop bx
sub bx,dx
mov dx,bx
push dx
mov ah,9
mov dx, offset msg5
int 21h
mov cx,10000
pop dx
call View
jmp exit
Divide: mov ah,09h
mov dx, offset msg2
int 21h
mov cx,0
call InputNo
push dx
mov ah,9
mov dx, offset msg3
int 21h
mov cx,0
call InputNo
pop bx
mov ax,bx
mov cx,dx
mov dx,0
mov bx,0
div cx
mov bx,dx
mov dx,ax
push bx
push dx
mov ah,9
mov dx, offset msg5
int 21h
mov cx,10000
pop dx
call View
pop bx
cmp bx,0
je exit
jmp exit