Integer arithmetic etc blahblahblah 3/18/16

.586
.MODEL FLAT, C

.DATA
order1Switch DB 1 ;Set to 0 if addition/multiplication/exponentiation, 1 if subtraction/division/modulus
order2Switch DB 0 ;Set to 0 if addition/subtraction, 1 if multiplication/division
order3Switch DB 1 ;Set to 0 if addition/subtraction/multiplication/division, 1 if exponentiation/modulus
a DD 7
b DD 2

.CODE

MAIN PROC
    mov ecx, 0 ;Set ECX to 0 for counter

    ; Initalize data register (EAX, accumulator) with 0
    mov eax, 0

    cmp order3Switch, 0
    jg ord3Exec

    cmp order2Switch, 0
    je ord1Exec
    jmp ord2Exec

    ord1Exec:
        add eax, a
        cmp order1Switch, 0
        je execAdd
        jmp execSub

    ord2Exec:
        cmp order1Switch, 0
        je execMulti
        jmp execDivi

    ord3Exec:
        cmp order1Switch, 0
        je execExp
        jmp execMod

    execAdd:
        call ADDITION
        jmp endSect

    execSub:
        call SUBTRACTION
        jmp endSect

    execMulti:
        call MULTIPLICATION
        jmp endSect

    execDivi:
        call DIVISION
        jmp endSect

    execExp:
        call EXPONENTIATION
        jmp endSect

    execMod:
        call MODULUS
        jmp endSect

    endSect:
        mov eax, eax
MAIN ENDP

ADDITION PROC
    add eax, b
    ret
ADDITION ENDP

SUBTRACTION PROC
    sub eax, b
    ret
SUBTRACTION ENDP

MULTIPLICATION PROC
    mov ecx, b
    multiply:
        add eax, a
        loop multiply
    ret
MULTIPLICATION ENDP

MULTIPLICATIONEXP PROC
    mov ecx, a
    multiply:
        add eax, a
        loop multiply
    ret
MULTIPLICATIONEXP ENDP

DIVISION PROC
    mov eax, a
    divi:
        sub eax, b
        inc ecx
        cmp eax, 0
        jg divi

    finish:
        cmp eax, 0
        jl fail
        mov eax, ecx
        ret

    fail:
        ;Numbers do not evenly divide
        ;Output 0, indicates failure
        mov eax, 0
        ret
DIVISION ENDP

EXPONENTIATION PROC
    mov edx, b
    dec edx
    expon:
        call MULTIPLICATIONEXP
        dec edx
        cmp edx, 0
        jne expon
    ret
EXPONENTIATION ENDP

MODULUS PROC
    mov eax, a
    divi:
        sub eax, b
        cmp eax, 0
        jg divi
        je finish
        jl modu

    finish:
        mov eax, 0
        ret

    modu:
        mov edx, 0
        sub edx, eax
        mov eax, edx
        ret
MODULUS ENDP

END