.model small
.stack 100h
.386


;--------------------------------------------------------------------;
; Daten & Variablen
;--------------------------------------------------------------------;
.data
    esc_code = 1Bh
    videospeicher = 0B800h
    adressanfang = 0F000h
    adressende = 0FA6Eh

    MSG_FIRST_NUM DB "Zahl 1:   "   ;10 gesamtänge
    MSG_SECOND_NUM DB "Zahl 2:   " ;10 Länge
    MSG_OPERATION DB "[+ - *]:   " ; 11 Länge
    RESULT_LINE DB "____________" ;17

    MSG_FAIL_NUM DB "  Keine gueltige Zahl!  "  ;20
    MSG_FAIL_OP DB "  Keine gueltige Operation!  "  ;25
    MSG_START_LINE db 03h

    MSG_START_TITLE db 0aah,0a9h," ",  0aah,0a9h, "  DER CALCULATOR  ",0aah,0a9h," ",  0aah,0a9h ;28
    MSG_START_SUBTITLE db "Addition, Subtraktion und Multiplikation" ;40
    MSG_START_SUBSUBTITLE db "Zahlen von 00 - 99" ;18

    MSG_MAN_TITLE DB "Anleitung:"   ;10
    MSG_MAN_FIRST DB "1. Zahl eingeben" ;16
    MSG_MAN_SECOND DB "2. Operation eingeben"   ;21
    MSG_MAN_THIRD DB "3. Zahl eingeben"     ;16
    MSG_MAN_CANCLE DB "Abbruch mit ESC"     ;15
    MSG_MAN_RESTART DB "Neustart mit L-Mausklick" ;24

    MSG_START_PRESENTED db "Proudly presented to you by Kevin & Florian!"
    MSG_EXIT_RESTART db "Noch eine Runde? (L/R -Maus)"  ;28 Länge

    vorzeichen db ?
    operator DB ?
    ten db 10

    counter DB ?
    num1_1 db ?
    num1_2 db ?
    num2_1 db ?
    num2_2 db ?

    colorNums     dw 0Ah
    colorTitle    dw 03h
    colorSubTitle dw 07h
    colorPresent  dw 089h
    colorLine     dw 0Ch
    colorRestart  dw 0Eh
    colorFail     dw 06Fh
    colorManual   dw 08h

    resultE DB ?, "$"
    resultT DB ?, "$"
    resultH DB ?, "$"
    resultX DB ?, "$"

;--------------------------------------------------------------------;
;   Code
;--------------------------------------------------------------------;
.code
    jmp start

;--------------------------------------------------------------------;
;   FEHLER
;--------------------------------------------------------------------;

    fehler:                                   ;Fehlermeldung für ungueltigen Input
        mov ax, 1300h
        mov bx, colorFail
        mov dh, 19                              ;ROW
        mov dl, 28
        mov cx, 24
        mov bp, offset MSG_FAIL_NUM
        int 10h

        mov cx, 900
        call delayLoop
        jmp start

    fehlerOp:
        mov ax, 1300h
        mov bx, colorFail
        mov dh, 19 ;row
        mov dl, 25
        mov cx, 29
        mov bp, offset MSG_FAIL_OP
        int 10h

        mov cx, 900
        call delayLoop
        jmp start

    delayLoop:
        mov ax, 60000
        loopx:
            dec ax
            jnz loopx
        dec cx
        jnz delayLoop
        ret

;--------------------------------------------------------------------;
; Programmstart
;--------------------------------------------------------------------;
   start:
        mov ax, @data
        mov ds, ax
        mov es, ax

        mov ah,0ch
        mov al,0
        int 21h

        mov ax, 3
        int 10h

        mov ax, 1
        int 33h

        call buildUi

        mov resultE, 0
        mov resultT, 0
        mov resultH, 0
        mov resultX, 0

        ;Eingabe der ersten Zahl
        ;Interrupt Systemfunktion, 09 = Zeichenkette darstellen
        mov ax, 1301h
        mov bx, colorNums
        mov dh, 9 ;row
        mov dl, 34
        mov cx, 10  ;+2
        mov bp, offset MSG_FIRST_NUM
        int 10h

        ;Interrupt Systemfunktion, 01 = Eingabe Lesen (mit Echo)
        ;1. Stelle
        mov ah,01h
        int 21h
        mov num1_1 ,al

        ;Falsche Eingabe 1. Stelle abfangen
        cmp num1_1, esc_code
        je shutdown
        cmp num1_1 , "0"
        jl fehler
        cmp num1_1 , "9"
        jg fehler

        sub al, 48
        mov num1_1 ,al

        ;2. Stelle
        mov ah,01h
        int 21h
        mov num1_2,al

        ;Falsche Eingabe 2. Stelle abfangen
        cmp num1_2, esc_code
        je shutdown
        cmp num1_2, "0"
        jl fehler
        cmp num1_2, "9"
        jg fehler

        sub al, 48
        mov num1_2,al



        ;Eingabe der Operation
        mov ax, 1301h
        mov bx, colorNums
        mov dh, 11 ;row
        mov dl, 34
        mov cx, 11  ;+1
        mov bp, offset MSG_OPERATION
        int 10h


        ;Operator in Variable speichern
        mov ah, 01
        int 21h
        mov operator, al

        ;Addition
        cmp operator, "+"
        je addition

        ;Subtraction
        cmp operator, "-"
        je subtraction

        ;Multiplication
        cmp operator, "*"
        je multiplication

        ;Exit
        cmp operator, esc_code
        je shutdown

        ;Failure
        jmp fehlerOp

;--------------------------------------------------------------------;
;   PROC: BUILD USER INTERFACE
;--------------------------------------------------------------------;
   buildUi PROC
            mov counter, 1
            poop:
                mov ax, 1300h
                mov bx, colorLine
                mov dh, 1;row
                mov dl, counter
                mov cx, 1
                mov bp, offset MSG_START_LINE
                int 10h

                mov ax, 1300h
                mov bx, colorLine
                mov dh, 23;row
                mov dl, counter
                mov cx, 1
                mov bp, offset MSG_START_LINE
                int 10h
                inc counter
                cmp counter, 79
                jne poop

            mov counter, 2
            noop:
                mov ax, 1300h
                mov bx, colorLine
                mov dh, counter;row
                mov dl, 1
                mov cx, 1
                mov bp, offset MSG_START_LINE
                int 10h

                mov ax, 1300h
                mov bx, colorLine
                mov dh, counter;row
                mov dl, 78
                mov cx, 1
                mov bp, offset MSG_START_LINE
                int 10h

                inc counter
                cmp counter, 23
                jne noop


            mov ax, 1300h
            mov bx, colorTitle
            mov dh, 2 ;row
            mov dl, 26
            mov cx, 28
            mov bp, offset MSG_START_TITLE
            int 10h

            mov ax, 1300h
            mov bx, colorSubTitle
            mov dh, 4 ;row
            mov dl, 20 ; column
            mov cx, 40
            mov bp, offset MSG_START_SUBTITLE
            int 10h

            mov ax, 1300h
            mov bx, colorSubTitle
            mov dh, 6 ;row
            mov dl, 31 ; column
            mov cx, 18
            mov bp, offset MSG_START_SUBSUBTITLE
            int 10h

            mov ax, 1300h
            mov bx, colorManual
            mov dh, 11 ;row
            mov dl, 3 ; column
            mov cx, 10
            mov bp, offset MSG_MAN_TITLE
            int 10h

            mov ax, 1300h
            mov bx, colorManual
            mov dh, 12 ;row
            mov dl, 4; column
            mov cx, 16
            mov bp, offset MSG_MAN_FIRST
            int 10h

            mov ax, 1300h
            mov bx, colorManual
            mov dh, 13 ;row
            mov dl, 4 ; column
            mov cx, 21
            mov bp, offset MSG_MAN_SECOND
            int 10h

            mov ax, 1300h
            mov bx, colorManual
            mov dh, 14 ;row
            mov dl, 4 ; column
            mov cx, 16
            mov bp, offset MSG_MAN_THIRD
            int 10h

            mov ax, 1300h
            mov bx, colorManual
            mov dh, 16 ;row
            mov dl, 4 ; column
            mov cx, 15
            mov bp, offset MSG_MAN_CANCLE
            int 10h

            mov ax, 1300h
            mov bx, colorManual
            mov dh, 17 ;row
            mov dl, 4 ; column
            mov cx, 24
            mov bp, offset MSG_MAN_RESTART
            int 10h

            mov ax, 1300h
            mov bx, colorPresent
            mov dh, 22 ;row
            mov dl, 18 ; column
            mov cx, 44
            mov bp, offset MSG_START_PRESENTED
            int 10h
            ret
    buildUi ENDP

;--------------------------------------------------------------------;
;   PROC: READ SECOND NUM
;--------------------------------------------------------------------;
    readSecondNum PROC
        ;Eingabe der zweiten Zahl
        ;Interrupt Systemfunktion, 09 = Zeichenkette darstellen
        mov ax, 1301h
        mov bx, colorNums
        mov dh, 13 ;row
        mov dl, 34
        mov cx, 10
        mov bp, offset MSG_SECOND_NUM
        int 10h

        ;Interrupt Systemfunktion, 01 = Eingabe Lesen (mit Echo)
        ;1. Stelle
        mov ah,01h
        int 21h
        mov num2_1, al

        ;Falsche Eingabe 1. Stelle abfangen
        cmp num2_1, esc_code
        je shutdown
        cmp num2_1, "0"
        jl fehler
        cmp num2_1, "9"
        jg fehler
        sub al, 48
        mov num2_1, al

        ;2. Stelle
        mov ah,01h
        int 21h
        mov num2_2,al

        ;Falsche Eingabe 2. Stelle abfangen
        cmp num2_2, esc_code
        je shutdown
        cmp num2_2, "0"
        jl fehler
        cmp num2_2, "9"
        jg fehler
        sub al, 48
        mov num2_2,al


        mov ax, 1301h
        mov bx, colorTitle
        mov dh, 14 ;row
        mov dl, 34
        mov cx, 12
        mov bp, offset RESULT_LINE
        int 10h
        ret
    readSecondNum ENDP

;--------------------------------------------------------------------;
;   ADDITION
;--------------------------------------------------------------------;
    addition:
        call readSecondNum
             ;Erste Zahl in AH und zweite dazu addieren

            mov al, num1_2
            add al, num2_2
            mov ah, 0
            aaa


            add ah, 48
            add al, 48

            add resultE, al
            add resultT, ah

            mov al, num1_1
            add al, resultT
            add al, num2_1
            mov ah, 0
            aaa

            add ah, 48
            add al, 48

            mov resultT, al
            add resultH, ah

            ;Resultmessage
            mov ah, 02h
            mov bh, 0
            mov dh, 16
            mov dl, 43
            int 10h

            mov ah, 2
            mov dl, resultH
            int 21h

            mov ah, 2
            mov dl, resultT
            int 21h

            mov ah, 2
            mov dl, resultE
            int 21h

        ;Calc finished
            jmp exit

;--------------------------------------------------------------------;
;   MULTIPLICATION
;--------------------------------------------------------------------;
    multiplication:
        call readSecondNum                        ;Read second number

        ;Calc Ones
        mov al, num1_2
        mov bl, num2_2
        mul bl
        aam                                       ;AH = Tens, AL, Ones

        add al, 48
        mov resultE, al                           ;AL = Ones
        mov cl, ah                                ;CL = Overflow for Tens

        ;Calc Tens
        xor ax, ax
        mov al, num1_2
        mov bl, num2_1
        mul bl
        aam                                       ;AH = Hundrets, AL = Tens

        add cl, al                                ;CL = Tens
        mov ch, ah                                ;CH = Overflow for Hundrets

        xor ax, ax
        mov al, num1_1
        mov bl, num2_2
        mul bl
        aam                                       ;AH, Hundrets, AL = Tens

        add al, cl                                ;CL = Tens
        add al, 48
        mov resultT, al
        add ch, ah                                ;CH = Hundrets

        ;Calc Hundrets & Thousands
        xor ax, ax
        mov al, num1_1
        mov bl, num2_1
        mul bl
        aam                                       ;AL = Thousands, AH = Hundrets

        add ah, 48
        mov resultX, ah
        add ch, al                                ;CH = Hundrets

        add ch, 48
        mov resultH, ch

        ;Calc overflow
        cmp resultT, "9"
        jng tensNotGreater9
        sub resultT, 10
        add resultH, 1
        tensNotGreater9:

        cmp resultH, "9"
        jng hundertsNotGreater9
        sub resultH, 10
        add resultX, 1
        hundertsNotGreater9:

        ;Resultmessage
        mov ah, 02h
        mov bh, 0
        mov dh, 15
        mov dl, 42
        int 10h

        mov ah, 2
        mov dl, resultX
        int 21h

        mov ah, 2
        mov dl, resultH
        int 21h

        mov ah, 2
        mov dl, resultT
        int 21h

        mov ah, 2
        mov dl, resultE
        int 21h

        jmp exit

;--------------------------------------------------------------------;
;   SUBTRACTION
;--------------------------------------------------------------------;
subtraction:
        call readSecondNum
        ;Cursor für das Ergebnis ausrichten
        mov ah, 02h
        mov bh, 0
        mov dh, 15
        mov dl, 43
        int 10h

        ;prüfen, ob Zahl1 groesser ist als Zahl2
        mov al, num1_1
        cmp al, num2_1
        jl negativesErgebnis
        jg positivesErgebnis
        je pruefeEinerStelle

        pruefeEinerStelle:
            mov al, num1_2
            cmp al, num2_2
            jl negativesErgebnis
            jnl positivesErgebnis

        positivesErgebnis:
            mov vorzeichen, ' '

            mov al, num1_1
            sub al, num2_1
            add al, 48
            mov resultT, al

            mov al, num1_2
            sub al, num2_2
            add al, 48
            mov resultE, al

            jmp uebertraegeUeberpruefen

        negativesErgebnis:
            mov vorzeichen, '-'

            mov al, num2_1
            sub al, num1_1
            add al, 48
            mov resultT, al

            mov al, num2_2
            sub al, num1_2
            add al, 48
            mov resultE, al

            jmp uebertraegeUeberpruefen

        uebertraegeUeberpruefen:
            cmp resultE, "0"
            jnl ergebnisSubtraktion
            add resultE, 10
            dec resultT
            jmp ergebnisSubtraktion

        ergebnisSubtraktion:
            ;Resultmessage
            mov ah, 02h
            mov bh, 0
            mov dh, 15
            mov dl, 43
            int 10h

            mov ah, 2
            mov dl, vorzeichen
            int 21h

            mov ah, 2
            mov dl, resultT
            int 21h

            mov ah, 2
            mov dl, resultE
            int 21h

        jmp exit

;--------------------------------------------------------------------;
;   EXIT
;--------------------------------------------------------------------;
    exit:
        xor ax, ax

        mov ax, 1301h
        mov bx, colorRestart
        mov dh, 18 ;row
        mov dl, 26
        mov cx, 28
        mov bp, offset MSG_EXIT_RESTART
        int 10h

        mouseClick:
            mov ah, 01h
            int 16h

            cmp al, esc_code
            je shutdown

            mov ax, 03
            int 033h

            cmp bx, 1
            je start
            cmp bx, 2
            je shutdown
            jmp mouseClick

;          ALTERNATIV: click "J" oder "j" zum restart
;          mov ah, 01
;          int 21h
;          mov bl, al

;          cmp al, 'j'                       ;Check if "j" is clicked -> restart
;          je start
;          cmp al, 'J'                       ;Check if "J" is clicked -> restart
;          je start

;          jmp shutdown                      ;Else shutdown

    shutdown:
            mov ax,3
            int 10h
            mov ax, 4c00h
            int 21h
END