Model small
stack 100h
Dataseg
    MenuText db "Welcome to the calculator : ",13,10,"To Add  -> + ",13,10,"To Sub  -> - ",13,10, "To Mul  -> *" ,13,10,"To Div  -> / ",13,10,"To Mod  -> % ",13,10,"To Pow  -> ^",13,10,"To Exit -> x","$"
    Num1Text db "Please Enter Number 1 (0-255) : " , "$"
    Num2Text db "Please Enter Number 2 (0-255) : " , "$"
    OperText db "Please Enter The Arithmetic : " , "$"
    ResultText db "The Result is : ","$"
    WrongOper db "Error : You Entered A Wrong Arithmetic , Please Repeat : ","$"
    Num1Str db 4 dup(?)
    Num2Str db 4 dup(?)
    Num1Int db ?
    Num2Int db ?
    ResultInt db ?
    ResultString db 4 dup(?)
    Oper db ?
    Temp dw ?

Codeseg
NewLine:                               ; פרוצדורה שיורדת שורה
    push ax
    push dx
    mov ah,2
    mov dl,13
    int 21h
    mov dl,10
    int 21h
    pop dx
    pop ax
    ret

PrintLine:                             ; פרוצדורה שמדפיסה מחרוזת
        push bp
        mov bp , sp
        push ax
        push dx
        mov dx , [bp+4]
        mov ah,9
        int 21h
        pop dx
        pop ax
        pop bp
    ret 2

StringInput:                           ;פרוצדורה שקולטת מחרוזת
    push bp
    mov bp , sp
    push ax
    push bx
    mov bx , [bp+4]

    Kelet:
        mov ah,1
        int 21h
        cmp al,0dH
        je Kelet2
        mov [bx],al
        inc bx
        jmp Kelet
    Kelet2:
        mov byte ptr[bx] , '$'
        pop bx
        pop ax
        pop bp
    ret 2

IntToStr:                         ; string לטיפוס int פרוצדורה שממירה מטיפוס
    push bp
    mov bp , sp
    push ax
    push bx
    push dx
    push cx
    mov cx , 0
    mov bx , [bp+4]
    mov al , [bx]
    mov bx , [bp+6]
    mov ah , 0
    mov dl , 10
    I1:
        cmp al,0
        je I2
        mov ah,0
        div dl
        push ax
        inc cx
        jmp I1
    I2:
        pop ax
        add ah,30H
        mov [bx] , ah
        inc bx
        loop I2
        mov byte ptr [bx] , '$'
        pop cx
        pop dx
        pop bx
        pop ax
        pop bp

    ret 4

StringToInt:                      ;int לטיפוס string פרוצדורה שממירה מטיפוס
    push bp
    mov bp , sp
    push ax
    push bx
    push dx
    mov ax , 0
    mov dl , 10
    mov bx , [bp+6]
    S1:
        cmp byte ptr [bx] , '$'
        je s2
        mul dl
        mov dh , [bx]
        sub dh , 30H
        add al , dh
        inc bx
        jmp s1
    S2:
        mov bx , [bp+4]
        mov [bx] , al
        pop dx
        pop bx
        pop ax
        pop bp

    ret 4

PlusDo:
    push ax
    mov al , Num1Int
    add al , Num2Int
    mov ResultInt , al
    pop ax
    ret

MinusDo:
    push ax
    mov al , Num1Int
    Sub al , Num2Int
    mov ResultInt , al
    pop ax
    ret

MultiDo:
    push ax
    mov al , Num1Int
    mul Num2Int
    ;mov ResultInt , byte ptr ax
    mov Temp , ax
    mov al , byte ptr Temp
    mov ResultInt , al
    pop ax
    ret

DivideDo:
    push ax
    ;mov ax , word ptr Num1Int
    mov ah , 0
    mov al , Num1Int
    div Num2Int
    mov ResultInt , al
    pop ax
    ret

ModDo:
    push ax
    ;mov ax , word ptr Num1Int
    mov ah , 0
    mov al , Num1Int
    div Num2Int
    mov ResultInt , ah
    pop ax
    ret

PowDo:
    push ax
    push cx
    mov ch , 0
    mov cl, Num2Int
    dec cl
    mov al , Num1Int
    Lo1:
        mul Num1Int
        mov Temp , ax
        mov al , byte ptr Temp
    loop Lo1
    mov ResultInt , al
    pop cx
    pop ax
    ret

;***********************************************************************

Start:
    mov ax,@data
    mov ds,ax


Menu:
    push offset MenuText
    call PrintLine
    call NewLine
;End Menu

NumbersInput:
    Num1Inp:
        push offset Num1Text
        call PrintLine
        call NewLine
        push offset Num1Str
        call StringInput
        call NewLine
    Num2Inp:
        push offset Num2Text
        call PrintLine
        call NewLine
        push offset Num2Str
        call StringInput
        call NewLine
;End NumbersInput

NumbersToInt:
    Num1ToInt:
        push offset Num1Str
        push offset Num1Int
        call StringToInt
    Num2ToInt:
        push offset Num2Str
        push offset Num2Int
        call StringToInt
;End NumbersToInt

OperationInput:
    push offset OperText
    call PrintLine
    call NewLine
    mov ah , 1
    int 21h
    mov Oper , al
    call NewLine
;End OperationInput

OperIfs:
    cmp Oper , 2BH
    je Plus
    cmp Oper , 2DH
    je Minus
    cmp Oper , 2AH
    je Multi
    cmp Oper , 2FH
    je Divide
    cmp Oper , 25H
    je ModTag
    cmp Oper , 5EH
    je Pow
    cmp Oper , 78H
    je Exit
    WrongOper1:
        push offset WrongOper
        call PrintLine
        jmp OperationInput
;End OperIfs

Plus:
    call PlusDo
    jmp ResultPrint
;End Plus

Minus:
    call MinusDo
    jmp ResultPrint
;End Minus

Multi:
    call MultiDo
    jmp ResultPrint
;End Multi

Divide:
    call DivideDo
    jmp ResultPrint
;End Divide

Pow:
    call PowDo
    jmp ResultPrint
;End Pow

ModTag:
    call ModDo
    jmp ResultPrint
;End ModTag

ResultPrint:
    push offset ResultString
    push offset ResultInt
    call IntToStr
    push offset ResultText
    call PrintLine
    call NewLine
    push offset ResultString
    call PrintLine
;End ResultPrint

Restart1:
    call NewLine
    call NewLine
    call NewLine
    jmp Menu

Exit:
    mov ax,4c00h
    int 21h
End Start